mi|e ^(H^P 'piihtarits ^0rtJ| Carolina ^tatc ®l|is boob foas presettteb b^ Elizabeth Stone THIS BOOK MUST NOT BE TAKEN FROM THE LIBRARY BUILDING. STRANGEWAYS' Veterinary Anatomy TWELFTH AMERICAN EDITION REVISED AND EDITED BY I. VAUGHAN, F.L.S., FZ.S. KELIiOW OF, AND EXAMINER ON OOMPARATIVE ANATOMY TO, THE ROYAL COLLEGE OF VETERINARY SURGEONS, I.ATE LECTURER ON ANATOMY AND ZOOLOGY AT THE NEW VETERINARY COLLEGE, EDINBURGH New York WILLIAM K. JENKINS CO. PUBLISHERS 851-853 Sixth Avenue 1908 TABLE OF CONTENTS. INTRODUCTION. ANATOMY, Vertebrata, . Domesticated Mammals, Domesticated Aves, Descriptive Anatomy, FA«B 1 3 4 5 6 CHAPTER I. OSTEOLOGY, Structure of bone, . Osseous tissue, Classes of bones, The Skeleton, . Axial Skeleton, Vertebrffi, . The Ribs, . Tbe Sternum, General view of the Skull, Cranial bones, Pacial bones, Appendicttlar Skeleton, Pectoral arch and limb, Pelvic arcli, Pelvic limb, Comparative Osteology, Ruminantia, Oranivora, . Camivora, . , Rodentia, . , Aves, 7 7 9 12 17 21 21 33 35 37 45 54 65 66 83 105 109 114 115 TABLE OF CONTENTS. CHAPTER IL ARTHEOLOGY, General Anatomy, . Classes of joints, Motion in joints; . Articulations of the Axial Skeleton, Vertebral articulations, Articulations of the Skull, Articulations of the Appendicular Skeleton, Pectoral limb, Pelvis and pelvic limb, Comparative Arthrologt, CHAPTER III MYOLOGY, Muscular tissue, Tendons, Fascia, Muscular nomenclature, Classification of muscles. Subcutaneous region, Tbe Head, . The Trunk, Pectoral limb, Pelvic limb. Arrangement of the fasciae. Table of muscular attachments, Comparative Myology, SPLANCHNOLOGY, . Epithelium, Mucous membranes, Serous membranes. Glands, Digestive System, Alimentary canal, . Mouth, . _ Palate, Tongue, Salivary glands, Teeth, CHAPTER IV, TABLE OF CONTENTS. Digestive System — continued. Pharynx, CEsophagus, Abdomen, . Stomach, . Intestines, . Accessory organs of digestion Liver, Pancreas, Spleen, Peritoneum, Kespiratort System, Nostrils, Kasal chambers, Larynx, Trachea, Thyroid and Thymus glands, Bronchi, Thorax, Pleurae, Lungs, Urinary System, Kidneys, Ureters, Bladder, Generative System, Male Organs, . Scrotum, . Spermatic cord, Testicle, . Vas deferens, Prostate gland, Cowper's glands, Urethra, Penis, Seminal fluid, Female Organs, Ovary, Fallopian tubes. Uterus, Vagina, Vulva, Ma.mnn fl.ry glands, Comparative SPLAHcHNOLoaY, 296 298 300 301 304 312 312 318 319 321 325 327 334 335 335 336 337 337 340 340 343 344 345 346 347 347 348 350 351 352 352 353 356 357 357 368 359 361 361 TABLE OF CONTENTS. CHAPTER y. ANGIOLOGY, , Blood- Vasculab System — Blood. Heart, Pericardium. Course of circulation, Arteries. Capillaries, . Pulmonary artery, . Common aorta. Posterior aorta, Internal iliac. External iliac. Anterior aorta, Brachial artery. Cephalic and Carotid arteries, Veins, . . . - Pulmonary and Systemic, Posterior cava, Portal vein. Iliac veins, . Anterior cava. Brachial vein, Jugular vein. Lymphatic System — Vessels, Glands, Lymph and Chyle, . Thoracic duct. Lymphatics of posterior region, abdominal viscera, thoracic viscera, thoracic walls, anterior region, Lymphatic vein, Comparative Anqiology, VARV 387 387 388 397 397 400 400 401 402 409 411 418 418 424 433 435 436 437 438 442 444 446 450 451 451 452 454 455 456 456 458 458 CHAPTER VI. NEUROLOGY, . Nervous tissue, Nerves, 465 466 467 TABLE OF CONTENTS. XXI PAOB Cerebro-Spinal System— Meninges, . 468 Spinal cord, . 471 Brain, . 473 Encephalic circulation, . 485 Cranial nerves. 490 Spinal nerves, . 502 Brachial plexus, . 508 Lumbo-sacral plexus, . . . .511 Sympathetic System— Cephalic portio n, . . . .515 Cervical portion, . . 516 Thoracic portion, . . 519 Lumbar portion, . • 521 Sacral portion, . 521 Comparative Neurology, 522 CHAPTER Vn. 625 STMJiiSlUljUlii, ORGANS OF SPECIAL SENSE. The Ear— External ear, .... . 525 Middle ear. ....•• 62(). Internal ear, . 529' The Eye— Tunics, . 53a Humours, . 536 Muscles, . . 537 Appendages, ORGANS OF SENSATION. 538 The Skin and its Appendages— Skin, . 541 Hair, . 543 Foot— Hoof, . 544 Soft parts of the foot, . 54» Comparative uEsthesiology, .... . 552 CHAPTER VIIL lYOLOGY,. . 555 Ovum after Fecundation, . . 556 Placenta, . 557 Umbilical cord. 558 Fcetal circulation, . . 559 Development of Foetus, . 561 ^Xll TABLE OF CONTENTS. APPENDIX. PAGE I, General directions for dissection, ..... 565 II. On a supernumerary oblique muscle of the eyeball, , , 575 III. On a muscle connected with the orbital periosteum, • 577 INDEX, .•.,..,*. 583 TABLE OF ILLUSTMTIONS. Tlate I. Skeleton of Horse, . II. Muscles of Horse— superficial layer, III. Muscles of Horse— deep layer, 17. Digestive and Urinary Organs of Horse, V. Heart and cHef blood-vessels of Horse, VI. Nervous System of Hors.e, PAO« . opposite page 21 161 . 193 . 274 . 400 . 503 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. Transverse sections through the body of a vertebrate brate animal — diagramatic, Transverse section of bone, . Longitudinal section of bone, Lacunae of bone. Section of ossifying cartilage, Skeleton of Horse, Transverse vertebral segment, Cervical vertebrae articulated, Cervical vertebra Skull seen from above, Inferior aspect of skull. Lateral view of the skull, Longitudinal section of the skull, Inferior maxilla. Bones of the hyoid series, Bones of the carpus, . Bones of the carpus, metacarpus, and digit, Development of foot, . Phalanges disarticulated, Lateral aspect of pelvis. Posterior aspect of femur, Bones of tarsus. Bones of tarsus, metatarsus, and digit, and an inverte- 10 10 16 18 22 24 25 37 39 41 43 62 64 72 73 77 79 85 89 94 TABLE OF ILLUSTRATIONS. FIG. 24. Posterior aspect of metatarsu?, 25. Skeleton of Ox, 26. SkuUofOx, . 27. Cardiac bone of Ox, . 28. Skull of Boar, 29. Skeleton of Hog, 30. Section of Hog's skull, 31. Skeleton of Dog, 32. Bones of Digits compared, 33. Clavicle of Dog, 34. Clavicle of Cat, 35. Os penis of Dog, 36. Skeleton of Bird, 37. Sternum of Bird, 38. Skull of Fowl, 39. Pectoral arch of Bird, 40. Pelvis of Bird, 41. Hyaline cartilage, 42. White fibrous tissue, . 43. Yellow elastic tissue, . 44. Adipose tissue, 45. Diarthrodial joint — diagram 40. Odontoid and superior cor- m on ligaments, 47. Costo-vertebral articulation — lateral aspect, 48. Costo-vertebral articulation — superior aspect, 49. Temporo-maxillary articulation, 50. Hyoid articulations, . 51. Ligaments of elbow joint, 52. Ligaments of carpus — anterior, 53. Deep ligaments of carpus — external 54. Deep ligaments of carpus— postero-intemal, 55. Superficial ligaments of carpus — posterior, 56. Sesamoidean and distal ligaments, , 57. Deep sesamoidean ligaments, 58. Navicular Mgaments, . 59. Sacral and pelvic ligaments, . 60. Sacral and pelvic ligaments— inferior view, 61. Ligaments of hip joint, 62. Ligaments of stifle joint, 63. Ligaments of stifle joint — posterior view, 64. Ligaments of tarsus — postero-intemal view, 65. Ligaments of tarsus — antero-extemal view, 66. Striated muscular fibres and tendon, . 67. Musciilar fibrillae, 68. Striated muscular fibres, 69. Non-striated muscular fibres, . TABLE OF ILLUSTRATIONS. MG. PAOB 70. Muscles of head— lateral view, . . . • 165 7 L Muscles of maxillary space. 1 171 72. Muscles of external ear, 175 73. Lateral cervical muscles, 185 74. Occipito-atlo-axoid muscles, 188 75. Pectoral muscles, 195 76. Sublumbar aud internal femoral muscles, . 206 77. Diaphragm, . . » . . • 209 78. External muscles of anterior limb, , 213 79. Internal muscles of anterior limb, , 216 80. Deep muscles of arm, 223 81. Flexor muscles of fore-foot, . 227 '82, Section of digit. 229 83. Deep muscles of liip. 233 84. Muscles of tliigb and haunch, 240 85. Anterior tibial muscles, 246 86. Posterior tibial muscles. 250 87. Teudons and ligaments of Ox's extremity, 262 88. Epithelial cells, . 270 89. Ciliated epithelium. 271 90. Muscles of tongue, palate, and pharynx, . 279 SI. Parotid and molar glands, . . 285 92. Mouth and salivary glands, . 286 93. Dentine, .... . 289 94. Enamel, .... . 290 95. Incisor and canine teeth. . 292 96. Structai-e of incisor tooth, . . 292 97. Structure of molar tooth, . 294 98. Stomach, .... . 301 99. Internal aspect of stomach, . . 303 100. The mesenteries, . 305 101. Section of mucous membrane of intestine. 1 . 306 102. Chyle magnided, . 307 103. Cajcum and great colon, . 309 104. Liver and diaphragm. . 313 105. Hepatic lobules magnified, . . 316 lOG. liUiary and pancreatic ducts, . 317 107. Pancreas, .... . 318 108. Spleen, .... . 319 109. Relations of abdominal viscera, . 320 110. Framework of nostril, . 324 1 11. Longitudinal section of head, . 326 112. Epiglottis, .... . 329 1 13. Ligaments of larynx — posterior view, . 330 114. Ligaments of larynx— anterior view, . 330 1 15. Muscles of larynx — lateral view, . 332 XXVI TABLE OF ILLUSTRATIONS. FIG. 116. Deep muscles of larynx — lateral view 117. Larynx laid open, 118. Respiratory organs, . 119. Capillaries of lung, . 120. Section of kidney, . 121. Structure of kidney, 122. Distribution of renal artery, 123. Male generative organs, 124. Testicle, 125. Diagram of structure of testicle, 126. Bladder and urethra, 127. Female urino-genital organs, 128. Female generative organs, . 129. Stomach of Ox, 130. Stomach of Sheep, . 131. Rimiiiiaut stomach opened, . 132. Stomach of Musk Deer, 133. Mesentery and intestines of Ox, 134. Caecimi of Ox, 135. Liver of Ox, 136. Kidney of Ox, 137. Section through vagina and bladder of Co-vv, 138. Teeth of Hog, 139. Stomach of Hog, 140. Caecum and colon of Hog, , 141. Liver of Hog, 142. Kidney of Hog, 143. Teeth of Caruivora, . 144. Stomach of Dog, 145. Cpecum and colon of Dog, 146. Stomach, liver, &c., of Dog, . 147. Teeth of Rodent, 148. Alimentary canal of Bird, . 149. Urino-genital organs of Bird, 150. Right side of heart — opened, 151. Left side of heart — opened, . 152. Muscular fibres from heart, . 153. Diagram of circulation, 154. Heart and large vessels in situ, 155. Abdominal branches of posterior aorta, 156. Arteries of crecum and colon, 157. Breaking up of posterior aorta, 158. Distribution of internal iliacs, 159. Arteries of thigh, . - 160. Arteries of leg, 161. Arteries of neck. TABLE OF ILLUSTRATIONS. Fto. 162. Arteries of fore-limb, 163. Arteries of head, 164. Facial arteries, 165. Posterior vena cava, . 166. Portal system, 167. Heart and great veins, 168. Ve ins of face and neck, 169. Section of lymphatic gland, 170. Lympbathic trunks, . 17 1. Circulation in Reptile, 1 72. Circulation in Fish, . 173. Circulation in Crustacean, 174. Nerve tissue, 1V5, Pacinian body, 176. Section of spinal cord, 177. Base of brain, l'?8. Brain viewed from above, 179. Lateral ventricles, 180. Cavities of brain — diagramatic, 181. Brain laid open, 182. Diagramatic section of brain, 183. Encephalic arteries, 184. Arteries at base of brain, 185. Origins of cranial nerves, 186. Nerves of eye, 187. Fifth nerve, 188. Facial nerves, 189. Posterior nerves of head, 190. Brachial plexus, 191. Carpal and metacarpal nerve, 192. Lumbo-sacral plexus, 193. Tarsal and metatarsal nerves, 194. Sympathetic ganglion, 195. Nerves of thorax, 196. Abdominal nerves, . 197. Conchal and annular cartilages, 198. Scutiform cartilage, . 199. Malleus, 200. Incus, 201. Stapes, 202. Tjpipanum, . 203. Diagram of ear, 204. Membranous labyrinth, 205. Diagram of eye, 206. Globe of eye, 207. Globe of eye — partly opened, PAOE 421 428 429 436 438 443 448 450 452 463 464 464 466 467 472 474 477 481 483 484 485 486 487 491 493 495 497 501 509 510 513 514 515 517 519 526' 526 527 527 527 528 529 531 533 TABLE OF ILLUSTRATIONS. FIG. PAOK 208. Pigment cells, 534 209. Iris, . 635 210, Globe of eye— opened, 536 211. Hoof,. 546 212. Solar aspect of hoof, . 547 213. Section of hom-tissue. . 548 214. Sensitive foot — solar aspect, . 55a 215. Sensitive wall. 551 216. FcEtus of Cow, 558 217. FcEtus of Bitch, 559 218, Foetal circulation. . 560 INTRODUCTION. Biology, the comprehensive science which treats of living or organised bodies, is divisible into two parts, the one dealing with the Vegetable, the other with the Animal Kingdom. Animal Anatomy, or Zootomy, has for its object the investigation of the animal frame, an investigation conducted by mechanically divid- ing it into its component parts, and studying their form, struc- ture, attachments, and relations. Anatomy may be Compai-ative, Special, or Transcendental, according to the scope and ultimate object in view. Thus, if more than one species of animal be under consideration, the' comparative anatomist takes note of their various deviations and similarities ; but, if the investiga- tions be confined to one variety of animal, as in Human Anatomy, the subject then becomes special. When Special Anatomy leads to the thorough investigation of one single variety, for the purpose of comparing other classes with it, the subject of such special study is termed a type. Comparative Anatomy, therefore, is not studied hy the indis- criminate comparison of one class with another, but by referring them to certain types or standards. Embracing as it ' does the structural investigation of the whole animal kingdom, Compara- tive Anatomy is closely related to the science of Zoology, the latter science aiming especially at the attainment of a scientific method of classification. Transcendental or Philosophical Ana- tomy seeks for analogies and developmental facts, which may guide the investigator in his search after primary anatomical types. Since the prosecution of such a study must assume a more or less profound knowledge of Comparative Anatomy, this 2 INTRODUCTION. abstruse branch of the science is merely alluded to here in, passing. If we consider a portion of the animal body with respect to its form, size, relative position, or structure, we are said to consider it anatomically ; but should we inquire into the use or function of such portion, or seek to know the changes undergone by it while in a living condition, then we are investigating it l^hysiologically. Such is a general distinction between the sciences of Anatomy and Physiology ; but it will readily be seen that they are to a great extent bound up in one another, since both the sciences must lend their aid to afford a complete description of any given organ or part. The branch treating solely of structure and form is termed Morphology. Histology, otherwise called General or Minute Anatomy, treats of the intimate structure of the tissues or materials of which the various parts of the body are composed. As the tissues present certain character- istics invisible to the naked eye, the microscope is largely employed by the histologist in his investigations. Embryology, from an anatomical point of view, is a science considering the various appearances presented by an animal after each of the many successive stages of its development, — from when it first appears as a mere speck of vitality until it has acquired the general characteristics of a perfect animal. Anatomy, in all the above-mentioned branches, deals only with normal or healthy material ; but should such material be in a diseased condition, the consideration of the changes it has conse- quently undergone is termed Morbid Anatomy. Surgical Anatomy embraces the description and investigation of such parts of the body as are most liable to be involved in surgical operations. The surgeon, by a competent knowledge of this branch of the subject, is enabled to operate with the maximum of safety and expedition, together with the minimum of pain and inconvenience to the patient. Anatomy in either of its aspects may be descriptive or practical. In the former, the student relies on books, diagrams, lectures, &c., for his information ; in the latter, he verifies descrip- tions by actual dissection and demonstration of the various structures in question. Veterinary Anatomy, in the full sense of the word, includes the anatomy of all the domesticated animals, and is, therefore, a branch of the comparative science, and the animal usually INTRODUCTION. 3 referred to as its type is the Horse, the Anatomy of which animal, or Hippotomy, is primarily considered in this WorK, while the deviations from the type, which make up the compara- tive branch of the subject, will be noted in their more important features, as fully as the scope of the work will permit. VEllTEBRATA. As all the domesticated animals belong to the sub-kingdom Vertebrata, it is of importance to gain a clear idea of the lead- ing characteristics of a vertebrate animal ; and, except in one or two of the lowest orders, these are well marked. The animal kingdom is divided into the /,. sub-kingdoms Invertebrata and Verte- brata. As the names would imply, the latter is distinguished from the former by its members possessing a vertebral column, or backbone, which forms, as it were, the axis of the bony framework, supports the head, and is placed dorsally, or in the region of the back, extending from one end -^ of the body to the other. It is pierced throughout the greater part of its extent by a canal called the neural canal, which is continuous with a cavity in the, head ^^°-*- ,, , ^, , ~, ... A, Diagramatic transverse .called the cramum. ihese cavities are section through the body of a occupied by centres, from which radiate vertebrate b a simUar sec- ^ •' . ' tion through a highly-organised the large series of nerves termed the invertebrate animal. cerehro-s-pinal system. Uoderneath the ,p";aT'n"1e'?cTntrL^; ?no[o. backbone there is a second series of nerve- chord; a, sympathetic nerve- ,7 .. , centres; €, Alimentary canal; centres — those oi the sympathetic system. /, visceral canaiwaii;g,Hffimai Thus in a vertebrate animal there are system.-^/ier NicnoLsoN. tiuo systems of nerves, whose centres are separated by a partition of bone. The remaining portion of the animal body may be regarded as a second cavity, or canal, which contains, in addition to the sympathetic system of nerves, the alimentary and the kcemal systems. The former runs the whole length _of ±he "body, being a canal which gives passage to the food ; the latter consists of 4 INTRODUCTION. a series of tubes, by which the blood passes through the body, both systems being supplied with many accessory organs. In the higher invertebrate animal we find no backbone, no neural canal, and no cerebro-spinal system of nerves ; but t' e visceral canal exists, and its contents correspond mostly with the structures found in the vertebrate. (See Fig. 1.) The lowest vertebrate animals known — the Lancelot, or A'>niohioxus, and the Lamprey — have no vertebral column, but they possess throughout Hfe a soft, gelatinous structure, the notochord, from which, in the higher vertebrates, the column becomes early developed. These may be regarded as exceptional or undeveloped forms. If we eliminate from the Vertebrata all the classes but the two highest — the Mamimalta and Aves — we shall further localise our subject, since these two classes contain all the animals which, as a rule, engage the attention of the veterinary anatomist, to whom the first of the two is of by far the greater importance. DOMESTICATED MAMMALS. It is sufficient to state that the Mammalia are .characterised by the females being provided with an apparatus which supplies milk for the nourishment of their young after birth. The horse, ass, ox. sheep, goat, camel, llama, pig, elephant, dog, cat, and rabbit are the mammalian vertebrates, usually included in the term "domesticated animals." The first eight of these belong to one of the most important of the natural orders, the Ungulata, or hoofed animals. The camel, llama, and elephant, not being domesticated, in the proper sense of the word, in Europe, the scope of the present work will not permit separate sections to be devoted to their description. UNGULATA. The Ungulata which included the hoofed quadrupeds, is a very large and important order, divided into two parts. One section, the Perissod,acUjla, includes the animals having an odd number of toes or digits ; the other, the ArtiodadyJa, contain- ing those with an even number. PERISSODAOTYLX. Equidm or Solidungula. — The horse and ass are referred, in the section Perissodactyla. to this family, which includes only the two genera Equus and Asinus : their most prominent external feature is the possession of only one perfect digit or finger on each extremity. Apparently there is but one cleariy defined species in the genus Equus, the features presented by the varieries which are INTRODUCTION, 5 "known as "breeds" being, in all probability, due to the pro- longed influence of external circumstances, such as locality, .treatment, climate and selection. In the Equidse the stomach is simple and comparatively small. ARTIODACTYLA. Ruminantia. — The ox, sheep, goat, camel, and llama belong to this section of ruminating animals, so named from their habit of remasticating their food. They, are all cloven-footed, or have two digits. Very generally the skull of the ruminant is provided with a pair of horns ; and the ox, sheep, and goat are classed as Cavicomia, their horns being hollow, and supported on bony cores. Ruminants are mostly without front teeth in the upper jaw, and their stomach is very large and complex. Omnivora. — The pig is classed in this section. Its teeth are of a mixed order, calculated to deal with many kinds of food, hence -the name Omnivora. The canine or eye teeth are very prominent, and in the male they project considerably as " tusks," which in the wilder varieties are formidable weapons. The stomach is intermediate in complexity between that of the ruminant and that of the horse. This animal has four digits, two long and two short on each extremity. The nose, or snout, is prominent, and rather cylindrical in form. CARNIVORA. Unlike any of the above-named animals, the dog and cat are placed in this natural order, an order characterised by large canine teeth, and by there being no lateral or grinding motion between tbe jaws. The anterior extremity is supplied with five, the posterior with four or five digits, which are terminated by sharp or blunt, retractile or non-retractile claws. The stomach is small, and the intestine comparatively short. RODENTIA. This natural order, to which the rabbit belongs, although an extensive order, is sufficiently distinguished by the possession of two large chisel-shaped incisor or front teeth, which are found in each jaw, the canine teeth being altogether wanting. DOMESTICATED AVES. Birds are distinguished from Mammals by their producing their young oviparously, or by hatching the egg outside the body. 6 INTRODUCTION. They never suckle their young, and have a covering of feathers- Such of these as we have to allude to belong either to the natural order Rasores or to the Natatores. the former including the terrestrial birds and pigeons, the latter the various aquatic species, distinguished by their web feet DESCRIPTIVE ANATOMY. Osteology is a term applied to that section of descriptive anatomy which treats of the bones. Arthrology to the considera- tion of the joints or modes of union between the bones, while by Myology is meant the doctrine of the muscular system. Splanch- nology treats of the viscera, Angiology of the circulatory and absorbent systems. Neurology deals with the nervous system. JEsthesiology with the organs of sense ; while Embryology, as before stated, is the consideration of the animal frame at periods preceding its birth. In this work the various departments are discussed in the order here given. The structures which are the subjects of the first three divisions are sometimes classed together as the Organs of Locomotion, for bones form the framework of the body and often act as levers ; the joints connect the bones, permitting more or less motion between them ; while the muscles move the bones, and so produce motion of a part of the body — or it may be locomotion, or change of situation in the entire frame. In the study of Comparative Anatomy the terms anaUjy and homology are frequently met with. Although these words are not unfrequently used indiscriminately, the following difference should be noted. Organs are said to be analogous when, though differing in structure, they perform the same function ; but when their functions are different, while, in the broad sense, they correspond in structure or form, they are said to be homologous. Thus the middle finger of the human hand is the homologue of the anterior digit of a horse, because they have the same general structure, and relation to the rest of the limb; but as the functions thf^y perform are quite dissimilar, they cannot be termed analogous. Again, the lungs of a mammal are analogous to the gills of a fish, for, though they differ widely in structure, position, and form, and are therefore not homologous, their ultimate use is the same — each of them being an apparatus in which is carried on the process of purifying the blood. CHAPTER I. OSTEOLOGY. STKUCTURE OF BONE. Bones are hard, yellowisli- white, insensitive bodies, wliich form the internal or e^icZoskeleton. give attachment to soft structures, and are of various sizes, forms, and densities. In the limbs the bones are usually more or less cylindrical, with expanded extremities, and not only effectually support the body, and afford leverage and attachment to the muscles, but, by uniting,, form the articulations or joints. Where cavities, such as the cranium, chest and pelvis, enclose viscera requiring protection, and support, the bones tend to assume a flat, expanded form. Living bone is bluish pink, insensitive, and elastic ; on ex- posure to air it becomes diseased, assumes a black or livid hue, and is extremely sensitive and painful; the teeth excepted, it is harder and of a higher specific gravity than any other animal tissue. Consisting as it does of inorganic salts deposited in a basis of animal matter, to the former it owes its density and hardness, to the latter, its elasticity and tenacity — the union rendering the tissue solid and elastic enough to obviate fracture from ordinary causes. Its components are so intimately blended that, to the naked eye, it appears homogeneous, but, by steeping in dilute hydrochloric, or other strong mineral acid, the earthy matter is dissolved, while the tough flexile animal cast is left. Again, if we expose it to the action of heat we get rid of the animal matter, and a white, brittle, earthy, chalky substance is left, retaining its original shape. The relative proportions of animal and earthy matter vary at different periods of life. In the young, the organic constitutes nearly one-half of the bone ; in the adult, it diminishes to about a third, while in old animals it is still less ; hence the bones of very old animals are brittle, and more liable to fracture. 8 OSTEOLOGY. The animal and earthy proportions do not vary in the true bone tissue, but there is a gradual filling up of the cavities originally occupied by fat cells, thus condensing the bone. The earthy ingredients consist chiefly of carbonate and phosphate of lime ; the animal matter of cartilage and connective tissue, vessels, membranes lining the cancellated structure and medullary cavities, and a quantity of fat. The following is an average analvsis of osseous tissue by Von Bibra : — Phosphate of T,ime, with trace of\ Fluoride Calcium, . . . J Carbonate of Lime, Phosphate of Magnesia, Soluble Salts, . ' . Femur ot old'sh^ep. Femur of 4-year old BuU. Femur of 6-year old Horse. Humerus of 6-year old Cat. 55-94 12-18 1-00 0-50 54-07 12-71 1-42 0-80 54-37 12-00 1-83 0-70 59-30 10-69 1-70 0-40 69-62 69-00 68-90 72-09 Cartilage, Fat, &c., 29-68 0-70 29-09 1-91 27-99 3-11 27-21 0-70 30-38 31-00 31-10 27-91 100-00 100-00 100-00 100-00 In adult bones, as above stated, the proportion of animal -matter is about a third, varying in different animals, and in different bones of the same animal. The bones of the young may have too great a proportion of animal matter, when they give way under the superincumbent weight, as in rachitis, when, ossifica- tion advancing, the animal becomes a cripple. The degree of hardness varies not only with the age, but also with the class of the animal, the bones of birds being white, hard, and brittle, especially those of the wings and legs; the bones of the chamois and its congeners are also very hard and brittle, whereas fish bones are soft and flexible. The bones of some fishes contain a very large proportion of animal matter, and these are known as the cartilaginous fishes. In different parts of the same skeleton they vary in hardness, the petrosal bone being the hardest one in the body ; the shank bones are also very hard and dense, while the ribs are soft and flexible. The leg bones of a thorough- hved horse are more comwact than those of a heavy cart-horse ; OSSEOUS TISSUE. 9 the latter are larger, but do not weigh as much in proportion^ because the shell, or outer layer, is more expanded and thinner, affordifflg greater surface for muscular attachments. Whereas, in the thorough-bred, a greater density of bone is necessary to withstand the intense concussion of speedy action ; therefore the bones are increased in thickness of shell, affording greater strength, without apparent increase in size. OSSEOUS TISSUE. In bone tissue there are two modifications of texture, the com- pact and the cancellated. The former — hard, dense, and ivory- like — is always situated externally ; the latter — porous and spongy — lies within. Although the compact -__^i1ii^>/i'-=^^^s:^- tissue appears uniformly dense, and destitute of por- osity, yet, if we transversely sectate the shaft of a long bone, and examine it under the microscope, by trans- mitted light, it is found to contain numerous round openings. These are called Haversian canals. They transmit blood-vessels, and run in a longitudinal or slightly oblique direction, opening on either the outer the peripheral and mterstitiallamellffi. or inner surface of the bone ; they also have many transverse branches of communica- tion, which are often of greater diameter than the trunks. These canals are from ^th to iTrrffth of^an inch in diameter, and surrounded by concentric layers or lamellce of bone, which are shady or opaque, and vary in number from two or three to six, the internal being most distinct, each succeeding one becoming less so. Between them may be seen many dark, irregulavly-oval objects — the minute reservoirs or lacunce, containing the hone-corpus- cles, from which numerous radiating processes occupy the- canal icul i ; the latter are minute canals, which establish a. communication between the Haversian canals and the lacun&.. On the external part of the shell of the compact tissue of long bones are several concentric osseous layers, the peripheral Fig. 2. Transverse section of compact osseous tissue. An Haversian canal, 3, is seen surronnded by concentric layers, forming an Haversian cylinder, 1. The dark objects between the lamella are lacunae ; 2 is a similar cylinder, showing also the canalicuU ; 4 4, Portions of 10 OSTEOLOGY. » Longitudinal section of osseous tissue, showing the arrangement of the Haversian canals. or periosteal lamelliB, passing completely rouud the shaft. There is also a corresponding concentric disposition of layers on the inner or medullary surface. Both these systems of lamellae are in a great measure destitute of Haversian canals, and are supplied with nutritive material by means of lacunae and cana- liculi, disposed as in the compact tissue generally. The average diameter of the canaliculi is Tinr^th of an inch. The lacunae are somewhat oval, and lie with their long diameters, which measure about rs^th of an inch, parallel to the lamellae ; their short diameter is about TreVoth of an inch. The compact tissue is therefore copiously supplied with nutriment by means of minute vessels, which enter from almost every conceiv- able point. Each Haversian canal may be considered a vas- cular longitudinal centre, round Y/hich successive concentric layers of bone are arranged, so as to form a dense cylindrical ossicle, a Haversian System or Cylinder. Series of these are repeated, and united by lamellae destitute of canal.s, but with numerous canaliculi and lacunse, and called the connecting or interstitial lamellce, the entire structure being encircled by the external peripheral lamellae, thus constituting the compact tissue, and in such a way as to combine strength and density with efficient nutrition, the nutritive material being conveyed by the canals, canaliculi, and lacunae ; the last two only transmit the Jltiid portion of the blood. The canaliculi interlace, and some pass directly through the lamellae to the central Haversian canal. The lamellae are in places pierced, and, as it were, pinned together by fibres, or fibrous bundles known as the perforating fibres of Sharpey ; some of these are derived from the perios- teum, and some even appear to be continued from inserted tendons and ligaments. Fig. 4. Lacuna; highly magnified lacuna ; h b. The canaliculi ; a, Cavity of those of the two lacunas on the left are seen to join each other. COVEEING OF BONE. 11 Cancellated or spongy tissue is always situated internally. It consists of a large number of fragile bony plates, with spaces between them called the cancelli ; there are lacunae and canali- culi, but no Haversian canals, their place being taken by the cancelli ; in the bones of the cranium this tissue is called the diploe, COVEEING OF BONE. The external surface of every bone is covered by a tough, fibro-vascular, inelastic membrane, the periosteum, excepting where tendons play over the bone, and its articular surfaces upon which there is a layer of cartilage. The periosteum, firmly adherent to the boue, contains minute blood-vessels, which are thickly distributed before entering the osseous tissue, and it consists of two layers — aa outer one, fibrous and protect- ive, and an inner one, which consists of fine connective tissue, contains bone-producing cells, or osteoblasts, and has been termed the osteogenic membrane. The inner layer is continued into the Haversian canals, a layer of cells also existing between the canal wall and the contained vessel. It affords support and protection to the bone, and attachment to tendons and ligaments, which frequently become continuous with it. It varies in thickness, being dense and strong on bones nearest the skin, and liable to injury ; in the horse, it is well devel- oped on the inner surface of the tibia, and over the anterior surfaces of the metacarpal and metatarsal bones. By its strength it sometimes retains the fragments of a bone in con- tact after an oblique fracture ; in the young, it is thicker and more vascular than in the adult. Blood-vessels which ramify in the periosteum pass directly to the bone ; the external surface of a bone is always studded with numerous foramina through which these enter. The periosteum, owing to its inelasticity, is, when inflamed, the seat of intense pain ; and should any part of it be stripped off, there is every probability of the denuded bone dying and exfoliating. It is most vascular near the joints, where it termi- nates by joining the articular cartilage, or passes to the next bone, but it never covers an articular surface. The internal or medullary cavities are lined by a more delicate vascular mem- brane, the endosteum. or medullary membrane, which is pro- longed into the cancelli and Haversian canals. It is very thin, consisting of delicate areolar tissue, filaments from which serve to support the marrow, the nutrient or medullary arteries, enter- 12 OSTEOLOGY. ing the bones by the so-called nutrient foramina, being chiefly distributed in it. The periosteum covering the bones of the cranial vault is called the pericranium. CONTENTS OF BONES. Bones contain Marrow, Connective Tissue, Blood-vessels, Lymphatics, and Nerves. Marroiv, as found in the shafts of long bones, is a soft, yellowish adipose or fatty material, which is contained in a delicate layer of connective tissue, and supported by inflective processes of the same. A few cells are found in yellow mar- row. Cancellated tissue contains what is termed the red marrow, a substance consisting for the most part of marroiv- jells, which are round and nucleated, but also containing some smaller objects resembling embryonic blood-corpuscles, and some very large cells. These latter contain numerous nuclei, and they are known as the giant cells, otherwise myeloplaxes. The connective tissue lining the medullary canal and cancelli forms the above-mentioned endosteum. The large bones of most birds in adult life contain air instead of marrow, but in the bones of a mammal in perfect health there is a considerable quantity of the latter, which becomes diminished in disease. Blood-vessels are numerous in bone tissue ; tlie arteries rami- fying in the periosteum gain the Haversian canals, the medul- lary artery enters by the nutrient foramen, and the arteries of the cancellated tissue pass through foramina situated near the articular surfaces. The veins are numerous, and, according to recent observation, do not generally accompany the arteries but occupy separate canals; tbe diploe in the cranial bones contains large dilated veins. Lymphatics exist, but little more is as yet known of them than that lymph spaces are found in the Haversian canals. Nerves likewise exist in osseous tissue, in its coverings, and also in marrow — accompanying the various blood-vessels. CLASSES OF BONES. Bones are classed as long, flat, and irregular. Long or cylindrical bones are found in the extremities, where they serve as levers, and pillars of support. Descriptively, a long bone is divisible into a centre or shaft and extremities. The shaft is cylindrical, and consists of a shell of compact tissue of varying thickness, which encloses the cancellated tissue and medullary canal, and is pierced by the medullary or nutrient CLASSES- OF BONES. 13 foramen; it is smallest in the centre, expanding towards the extremities, and is circular, oval, or prismoid in form. "When a long bone is placed nearly vertically uuder the body, the internal wall of its shaft is usually the thickest. When obliquely placed, the thick portions of the shaft correspond with the lines which would indicate the direction of pressure produced by the animal's weight. Long bones are never straight ; they may be twisted, as is the humerus, and, if bent, are generally convex on their exbosed surfaces, the shell being thickest on the concave side. The extremities of long bones always exceed the shaft in cir- cumference, and are remarkable for the irregularity of their outline; they are expanded and roughened, to afford surface for the attachment of tendons and ligaments, .-their protuberances also materially increasing the mechanical power of muscles by serving as pulleys over which the tendons play. The' extremities are composed of cancellated, with a thin layer of compact, tissue, the cancellated getting gradually less dense towards the centre of the shaft, which is occupied by the medullary canal. While the extremities exceed the shaft in circumference, their weight is not relatively greater — their increase being due to a diffusion and expansion of material, not to an addition of substance. This arrangement hghtens and strengthens the bone, besides filling its cavities with an elastic material to resist concussion. The hardest part of a bone is usually the thin portion lying next to the articular surface ; it is only found when the bone is fully developed, and it rests upon a series of arches formed by the cancelli : this thin layer is covered with cartilage. Excepting on their articulating surfaces, the extremities of long bones are copiously pierced by foramina, which chiefly transmit blood-vessels to and from the interior. Flat or tahalar hones afford extensive surface for muscular attachment, and help to enclose cavities containing important organs. Thus, the cranium protects the brain, the scapula and ribs protect the respiratory organs and heart. Flat bones are composed of two thin expanded plates of compact tissue, rarely quite parallel to each other, and enclosing a cancellated structure between them. The internal is considerably harder than the external plate, but not so thick or tough, the outer being more elastic and less liable to fracture ; the connecting cancellated tissue is plentifully supplied with blood-vessels. In the bones of the cranium, the compact plates are called the 14 OSTEOLOGY. tables, and the spongy tissue between, the diploe' ; the tables also in some facial bones may be widely separated, with air cavities between them. Irregular hones include all which are classed with the fore- going. They are found in the vertebral column, in the skull, and also in the limbs. They usually possess many angles and indentations, with surfaces for articulation aud tendinous attachment, and consist of a thin, dense, external case of compact bone enclosing cancellated tissue. In proportion to their size they present a much larger extent of articular surface and greater mechanical strength than any other class. SURFACES OF BONES. No bone is strictly geometrical in form, although, to a casual observer, some may appear so. The chief irregularities consist of certain eminences and depressions, a knowledge of which is one of the first requisites in the study of osteology. Eminences and depressions Qxe articular or non-articular ; the former are clothed with cartilage, and assist in the formation of joints. Non-articular eminences exist extensively on the external surfaces of most bones, and receive the attachments of tendons and ligaments. They are of various shapes, sizes, and densities, and frequently named from their real or supposed resemblance to some known object. The term process or apophysis, may be generally applied to prominent- elevations, but processes so called are not necessarily non-articular, and certain other terms are, rather arbitrarily, applied. A spine is an elevation which tends to become pointed ; a tubercle is a small blunt projection, which, if more developed, would be called a tuberosity, while the name trochanter is applied to the largest and most prominent of these A crest or ridge implies a roughened line or border. Non-articular depressions may serve as channels of trans- mission, passing completely through a bone or part of a bone, and may bear either of the names foramen, canal, aqueduct, or w.eatus, the first name being the most used ; or they may be blind cavities in the surface of jhe bone, and if roughened for the attachment of tendons or ligaments, the term fossa is some- times applied to them. The terms notch and fissure indicate depressions or grooves, which transmit various structures, and the approximation of two notches in contiguous bones . sometimes forms a foramen. When we find a depression leading to two or more foramina it may be termed an hiatus. DEVELOPMENT OF BONE. 15 Articular eminences. — A caput or head is a more or less semi- spherical projection, supported by a roughened and constricted cervix or neck. An ovoid convexity is called a condyle; and often condyles are found in pairs, the articular surfaces of which may be continuous or separated. A trochlea is an articular surface presenting a pulley-like appearance. Articular depressions. — A glenoid cavity is shallow, and may be cup-like, while a cavity is called cotyloid when it is deeper. The term facet is often applied to articular surfaces, which may be large, but are not well marked either as elevations or depressions. The rough irregularities of surface are more distinctly marked in the bones of the horse than in those of most other animals; their size is always proportionally greater in well-bred animals ; in heavy, coarsely-bred horses, which possess great strength but little activity, they are smaller in proportion to the absolute size of the bones. DEVELOPMENT OF BONE. Although the bones of the foal, calf, and young of many other large quadrupeds, possess greater solidity at birth than those of the human infant, yet they all pass through certain progressive stages of development before arriving at that degree of density which they ultimately possess. The tracing of future bone is recognised, about the seventh week of foetal development, in local collections of soft, granular, gelatinous pulp, which becomes gradually flooded with nucleated cells, held together by an opaque, intercellular basis or matrix, which, with the cells equally dis- tributed through it, forms te'mporary cartilage — a material closely resembling in its properties ordinary gristle. The process of ossification, or conversion of cartilage into bone, begins at certain fixed points, and gradually spreads ; these points are called ossific centres, or points of ossification. When this conversion commences, that part of the cartilage about to become ossified is permeated by large channels for the passage of the blood-vessels which convey the bone-earth ; and the cells, instead of being equally distributed throughout the matrix, become arranged in parallel groups, and increase in number, those nearest the point of ossification enlarging. Matter, in the form of very minute granules, is now deposited in this column of intercellular or hyaline substance, as well as between each cell. Ossification of the cell walls ensues, which is followed by the absorption of the osseous matter between the cells, converting what was a row of closed cells into a tube, which is a rudiment- 16 OSTEOLOGY. irj Haversian canal, no trace being left of the nucleus of the original cartilage corpuscle ; but there are numerous very minute reddish granules, which almost fill the cavity, and are concerned in the formation of blood-vessels, which now begin to appear. The ossific parietes of the cartilage cells lining the tube, at first thin, enlarge and thicken by successive layers of dense osseous matter, and thus produce the concentric lamellae, the lamella last formed pushing out the older one, until what was the lining of the tube becomes the external lamella of an Haversian system, while the ossific matter which was deposited in the column of intercellular material, becomes the connecting lamellae between the Haversian cylinders. In long bones this ossific process commences in the centre of Fig. 5. Section of ossifying cartilage magnified. On the left the cells are becoming arranged in rows ; while to the right, between the rows, the earthy material is being deposited. the shaft, gradually spreading to the es tremities, in which there are separate points of ossification ; there are generally three such points, one for the shaft, and one for each extremity, the develop- ing shaft being called the diaphysis, the eictremities the epiphyses. When any process is superadded, as the trochanter of the femur, which possesses a distinct point of ossification, it may be termed an apophysis. As ossification commences in the shaft, there are for some time after birth, interveqing portions of un ossified cartilage, marked by a deep ring in the dried long bones of young animals ; they disappear at variable periods, the portions of bone hitherto imperfectly united becoming consolidated into one firm mass. The bone increases in length by growth of the unossified ring, uniting the shaft and epiphysis, until the ring fills up, when growth is completed. Should an epiphysis unite with the diaphysis prematurely, by acceleration of the process of ossifi- cation through disease, growth being thus arrested, the bone will be shorter than its fellow. The shaft of a long bone increases in SKELETON OF THE HORSE. 17 circumference by deposits of new hone on its external surface, derived not from eartilage, but from membrane — the. inner layer of the periosteum, which has been termed the osteogenic mem- Irane. .In the periosteum there are two layers or strata — an outer, strong and fibrous ; an inner, soft, and containing osteo- blastic cells, which, after undergoing certain changes, produce layers of new bone; the process is termed intramembranous, as opposed to intracartilaginous ossification. This goes on till the bone has reached its full development, when Haversian systems cease to be formed, and then, as a climax, the peri- pheral lamellae are formed, and the medullary canal enlarges by internal absorption. In flat bones, ossification usually radiates from a centre, and is directed by the membrane investing each surface of the bone; some of them possess numerous apophyses. Ossification is completed in some bones much earlier than in others, and at birth those which are required for support and progression are farthest advanced. The bones of the cranial vault are developed, not from carti- lage, but from membrane. In early foetal life the brain is covered by two membranes, closely united— viz., the pericranium and dura mater ; between these, bone becomes developed from radiating ossific centres. The Skeleton. The internal framework on which the animal body is built is termed the Endoskeleton, while the outer casing which deter- mines the shape and appearance of the animal is the Exoskele- TON ; in some of the lower animals the latter assumes the form of a calcareous case, in others it is scaly, in others again, bony. The exoskeleton of the higher animals consists of the skin and its appended modifications, which will be described in a future sec- tion of the work. By the term skeleton is generally understood the endoskeleton, or bones of an animal, held in their relative positions, or articulated by wires or screws, in which case all the soft tissues are first removed, and the preparation is termed an artificial skeleton : but if those soft structures, whicli, in the living animal, join the bones together, are allowed to remain, dried, and preserved, then the preparation is a natural skeleton. As the skeleton has two sides or halves, the majority of the bones exist in pairs. There is, however, a central chain of single bones, formed by the back bones or vertebrae and the median C 18 OSTEOLOGY. FlQ. 6. SKELETON OF THE HOESE (Solidtjngula). Axial Skeleton. the skull. Cr*nial Bones. — a. Occipital. 1 ; 6, Wormian. 1 ; c. Parietal, 2 ; d. Frontal, 2 ; «, Temporal, 2; Sphenoid. 1 ; Ethmoid. 1 ; Auditory ossicles. 8. Facial Bones.— h, Nasal, 2: g. Lachrymal. 2 ; /, Malar, 2 ; i, Superior maxilla, 2; fc, Premaxilla, 2 ; Palatine. 2 ; Pterygoid. 2 : Vomer. 1 : Turbinals. 4 : I, Inferior maxilla. 1 ; Hyoid (segments), 5. Teeth :—m, Incisors, 12 ; n, Canines. 4 : o, Molars. 24. The Trunk.— p-v, Cervical vertebrse. 7 : w, Dorsal vertebrae. 18 ; x, Lumbar vertebrae, 6 ; y, Sacrum, 1 ; :, Coccygeal vertebrae (variable), 18 ; a'a', Kibs, 36 ; " Sternum (6-7 Stemebrae), 1 ; S Costal cartilages Appendioulah Skeleton. rECTOR.^L LIMB. e'. Scapula, 2 ; f. Humerus, 2 , g', Radius, 2 ; A', Ulna. 2. Carpus :— i', Trapesium. 2 : f. Cunei- form, 2 : V, Lunar, 2 ; tn'. Scaphoid. 2 ; n', Unciform, 2 ; o', Magnum, 2 ; p'. Trapezoid, 2 ; g', Pisiform. 2. Metacarpus r—r". Large bone. 2; s'. Small bone, 4. Digit :— it'. Proximal phalanges, 2; «/, Median phalanges, 2; w'. Distal phalanges, 2; f. Large sesamoids, 4: Small sesamoids, 2. -6', lUum. PELVIC LIMB, ! ; d'. Ischium. : : C, Pubis, 2. ", Fibula, 2. Tarsus : Pelvis.— Ob Innominatum The Limb.—y', Femur. 2 ; y, Patella. 2 ; a". Tibia, 2 ; 6", Fibula, 2. Tarsus :— c". Calcaneum, 2 : d", Astragalus, 2 ; e". Cuboid. 2 ; /", Cuneiforme magnum, 2 ; g", Cuneiforme medium, 2 : h", Cuneiforme parvum. 2. Metatarsus: — Large bone. 2; Small bone, 4. Digit :— Proximal phalanges, 2 ; Median phalanges, 2; Distal phalanges, 2 : Large sesamoids, 4 ; Small sesamoids, 2. The Horse's Skeleton, as here considered, consists of 256 part*. SKELETON OF THE HOESE. !» seo-ments of tbe head, extending the whole length of the frame- work, and uniting its lateral halves. But even these single bones present the same shape on either side of their central line; hence, if a skeleton were divided longitudinally, exactly- in the median plane, the two halves would correspond. This " right and left," or double arrangement of parts, is termed bilateral syratnetry. Anatomists differ as to the number of bones composing the skeleton, some enumerating all ossific bodies, including the teeth and sesamoids, which others eliminate; some, again, njgard certain cranial bones as single, other authorities as double. It is of little practical importance which view be taken ; it will be found that there are about 216 separate bones; or, including the teeth, 256 pieces in the skeleton of the horse. In speaking of the anatomical position and relation of bones as of other structures, continual reference is made to imaginary lines or planes. The skeleton of the quadruped, as well as that of man, is, in an anatomical sense, viewed from before ; but man, being erect, with the long axis of his body in a vertical position, whilst that of the quadruped is horizontal, corresponding organs do not always present themselves to observation from the same point of view. With reference to quadrupeds, imaginary planes are supposed to lie as follows : — A longitudinal median vertical plane descends through the centre of the head, vertebral chain, and trunk, midway between the right and left extremities, to the ground, dividing the body into two exact halves ; right and left lateral vertical planes are placed parallel to the former, but external to the body ; at right-angles to the above an anterior vertical plane is placed in front, and a posterior vertical one behind ; a superior horizontal plane lies above the body, between the anterior and posterior vertical planes ; while parallel with the superior is an inferior horizontal plane, placed under the feet. The external surface of an organ or region is that which faces the lateral plane on the side where the organ is situated. The internal surface faces the median plane of the body, the anterior surface the anterior vertical, the posterior surface the posterior vertical plane, while the superior and inferior surfaces are those facing their respective superior and inferior planes. This imagin- ary index may be applied to any region, as well as to the entire body. Modifications of these terms are used when it is requisite to point out the precise situation of a structui-e. For example, take 20 OSTEOLOGY. the anterior limb, and suppose it encompassed by the planes ut supra. If wje wish to describe the situation of any object on the upper part of its lateral region, the term supero-lateral would be used; if the object were situated at. the lower lateral part, then infero-lateral. Similar modifications of terms are, of course, applicable to the anterior and posterior surfaces. Supero-anterior implies the superior part of the anterior region, and antero- superior the anterior part of the superior region. For description, structures are frequently divided into two or more parts ; thus we allude to the superior, middle, or inferior third of an object. The end of a structure which is nearest to the vertebral column is often termed the x>roximal, while the remote end is termed the distal extremity. DIVISION OF THE SKELETON. The limbs, with their media of attachment, form the Appendiculak Skeleton ; while the remaining portion of the structure, consisting of the skull, vertebrae, ribs, and breast-bone, is called the Axial Skeleton. By many authorities the skull is regarded as being formed of a number of modified vertebrae, while the ribs and breast-bone, or sternum, are considered parts of complete vertebral segments. Taking this view, the term axial skeleton would be synonymous with vertebral column. In this work we first describe the axial skeleton, dividing it into the vertebral column and the skull, afterwards treating of the appendicular skeleton. The following Table will exhibit this division : — Axial Skeleton. Cervical E,egion. , Dorsal Region. < Vertebral; I Sternum. Column. \ Lumbar Region. / Sacral Region. • V Coccygeal Region. f Cranium t Face. Apjjendicular Skeleton. Pectoral Arcli and Limb Pelvic Arch and Limb. Skill EXPLANATION OF PLATE L Skeleton of the Horse, Showing its relation to the convour of the animal, viewed laterally. A. Temporal fossa. B. Inferior maxilla. C. Atlas. D. Dentata. E. Cervical vertebrae. F. Dorsal do. G. Lumbar do. H. Sacral do. I. Coccygeal do.'' J. Scapula. K. Humerus. L. Radius. L'. Ulna. M. Carpus. N. Trapezium. 0. Metacarpus. P, b. Os suffraginis. Q, c. Sesamoids. R, d. Os coronae. S, e. Os pedis. TT. Ribs. U. Ilium. V, Femur. X. Patella. Y. Tibia. V. Fibula. Z. Tarsus. a. Metatarsus. /. Ligamentum nucliae, funicular por* tion. /'. Laraellar portion. 1. Zygoma. 2. Orbital fossa. 3. Nasal peak. 4. Incisor teetli. 4'. Canine teeth. 5. Molar teeth. S. External humeral trochanter. 7 7. Scapular fosste. 8. Coracoid apophysis. 9. Cartilage of prolongation. 10. Deltoid ridge, and external tuber- osity. 11. Olecranon. 12. Costal cartilages. 13. Anterior iliac spine. 14. Ischium. 15. Trochanter major. 16. Trochanter minor. 18. Anterior tibial tuberosity. 19. Calcaneum. 2020. Small metacarpal and metatarsal, or splint bones. true vertebile. 21 Axial Skeleton. VERTEBRAL COLUMi«'. The vertebral or spinal column may be considered the found- ation of the skeleton, from which all othei' parts proceed. Ex- tending the whole length of the body, it consists of a series of single bones, termed vertehrce, firmly united, and it presents a succession of curves ; thus, in the horse, the neck, back, and croup are usually curved, while the loins are nearly straight. The vertebral chain may be divided into five regions, exclusive of the cranial portion, which we regard collectively as the skull. These are the cervical, dorsal, lumbar, sacral, and coccygeal — respectively the regions of the neck, back, loins, croup, and tail ; and, while all possess certain- points of conformation in common, special peculiarities distinguish the vertebrae of any one region from those of another. Vertebras are either true or false; true vertebrae possess certain typical parts, which they retain throughout the life of the animal, and they never, in health, unite by ossification ; while false vertebrae either do not possess the essential characters of true, or they may become so united. TRUE VERTEBRAE. A true vertebra consists of a body or centi'uni, an arch, called the neural arch, notches, and spinous, transverse, and articular processes. The body is the solid block of bone on which all the other parts are built, and which, in quadrupeds, lies below the spinal canal. Its anterior end is convex, and its posterior correspondingly concave, both being discs of compact bone roughened for the attachment of the soft intervertebral substance. Its upper or spinal surface is flattened or slightly concave, its inferior surface being convex, and sometimes terminating in a spinous process or prominent ridge. The neural arch or ring rises from the supero-lateral surfaces of the body by two processes of bone termed pedicles, from each of which a plate of bone, the lamina, expands and passes inwards, the iinion of the laminae in the median line completing the arch, which encloses the neural canal or spinal foramen. 22 OSTEOLOGY. The notches are excavations in the anterior and posterior sur- faces of each pedicle, so placed that when the vertebras are in situ the botch in the posterior part of one pedicle corresponds with that in the anterior of the next, the two forming a large opening, called the intervertebral foramen, which leads to the neural canal and gives passage to the spinal nerve and blood-vessels. Each true vertebra, with the exception of the two anterior cervical ones, has four oblique or aHicular processes (zyga- pophyses) on the superior and lateral parts of the arch. The faces of the anterior of these processes are directed upwards and inwards, those of the posterior downwards and outwards ; as their name implies, they articulate and form joints with the corresponding processes of contiguous vertebrae. In some of the dorsal and lumbar segments of certain animals, the anterior zygapophyses have processes which project above the level of the articular facets; these are the mammillary processes (meta- pephyses). The transverse processes (diapophyses), one on each side, spring from the sides of the body and pedicle, and are projec- tions varying much in size and shape in the different regions. Between the anterior zygapophysis and the metapophysis in some animals there may be another small emin- ence projecting backwards (anapophysis). The spinous processes are superior and inferior. The superior or neural spine (neurapophysis), formed by the union of the laminee, and surmounting the centre of the arch, is sometimes of great size and strength, but varies much in development in the different regions of the same animal. The inferior (hypapophyses) are for the most part rudimentary, and can scarcely be said to exist, except in the cervical region, where they project from the inferior central line of the bodies. The centra or bodies of the vertebrae, placed in natural apposition, thus form a central bony column, to which the arches and processes are attached ; the arches, with their connecting ligaments, form superiorly a cavity, the spinal or neural canal. '^^.f^ Fig. 7. Diagramatic transverse sec- tion from the skeleton of a mammalian thoiax, showius the chief features of a perfect vertebral segment. 1, Neural spine, 2,Lamina(neurapophy- sis); 3, Pedicle; 4, Neural arch; 5. centrum; 6, Inferior Spine (hypapophysis) : 7 7, Haemal arch ; 8,Rib(pleurapophysis); 9, Costal cartilage (haema- pophysis) ; 10, Sternebra . 11, Hseraal spine. CERVICAL VERTEBRA. 23 -which extends from the head to the tail, and contains the spinai cord, with its membranes and blood-vessels; the articular pro- cesses strengthen the connections of the vertebrae, while the spinous and transverse processes are levers to which muscles are attached, their development having great influence on the physical conformation and capabilities of the animal The ribs may be regarded as continuations of the dorsal transverse processes ; they form the inferior or hasmal arch of their own region. FALSE VERTEBR2E. The false vertehrce are found in the sacrum, which con- sists of vertebral segments united by the ossification of their connecting material, and in the coccyx, the skeleton of which consists of rudimentary or imperfectly-developed vertebrae. The sacral segments in the early stages of life are separable, and they present all the characteristics of true vertebrae. CERVICAL VERTEBRiE. General Features. (Fia. 8.) There are seven cervical vertehrce in all the Mammalia, with the exception of the Three-toed Sloth, which has nine, and one of the Sea-cows, which has six. They are numbered in order from the head, the first receiving the special name of atla,8, and the second that of axis or vertebra dentata ; these, with the sixth and seventh, differ from the rest, which are essentially alike. The centra or bodies of the cervical vertebrae are larger and longer than those of any other true vertebrae, and frequently measure upwards of four inches in length ; they are quadrangular in shape, their anterior extremity or head being convex and some- what heart-shaped, with the apex downwards, while the posterior extremity presents a corresponding cup-hke cavity. The flexi- bility of the neck is partly due to these convexities and cavities, which are more pronounced in the cervical region than in other parts of the column. The superior surface is flattened, and pre- sents, close to the pedicle on each side, a distinct furrow, which contains the spinal vein ; these lateral furrows are united by 24 OSTEOLOGY. means of a central transverse furrow, and partly covered by a thin bony plate, to which the superior common ligament is attached. The inferior surface presents a longitudinal process or ridge, the inferior, spinous process, which increases in size as it approaches 8 o 'o ^ I o g s " g I « I 2 I 2 ^ o a a a a. o £ o « '^" '^. I .I S ^ S ". g ^- 6 §• I £ l| S3 1-2 S s f.a the posterior end of the bone, where it terminates in a projecting tuberosity, which gives attachment to the longus colli muscle. The lateral surfaces of the body, above the inferior spine, are flattened, and somewhat excavated. CERVICAL VERTEBRA. 25 The superior spinalis processes or neural spines are mostly Tudimentaxy, and rise from the centre •of the quadrilateral space between the oblique processes. They are bifid posteriorly, the ligamentum nuchse and spinalis colli muscle being attached in the bifurcation. The transverse processes, broad, short, strong, and irregular in shape, ' p^^ g pass directly outwards, and divide ^^^^ ^^^^ ^^^ ^^ ^ ^^ ^^^ into two parts one projecting an- bra of a Horse, l, JSreural spine ; 2, Ah- . p . 1 1,1 ,1 , terior oblique processes; 3, Posterior terO-infenorly, and the other pOSterO- oblique processes; 5, convex anterior end. inferiorly. They increase in size as and 9, concave posterior end of the cen- *' "' 1 11 /. trum; 6, Anterior ends of tran-sversepro- they extend backwards, and all of cesses; and 7, Posterior end of nght one; them, except the seventh, are S, inferior process, or hypapophysi.. pierced by the vertebral foramen, through which pass the verte- bral artery and vein. These processes give attachment to the serratus magnus, splenius, longus colli, intransversalis colli, levator humeri, and other muscles acting upon the head and neck. The articular processes, larger than in any other region, have flattened oval articular surfaces ; the anterior two look upwards and inwards, while the posterior look downwards and outwards. The articular processes of the posterior five cervical vertebrae give attachment to the complexus major, trachelo mastoideus, and spinalis colli muscles. The arches, stronger than in any other region, enclose the spinal canal, which progressively increases in size in the direction of the dorsal vertebrae, its vertical diameter being the greater. The notches' of the three posterior cervical vertebrae are also larger than the rest. Viewed in situ, it is seen that the transverse processes of the three central cervical vertebrae are largest and strongest, with the exception of that of the first, and they can be detected under the investing mus parts, the internal of which is prolonged into the inferior tnrbinal bone, the external, which is the smallest, having an elevation on its floor caused by the root of the fourth molar tooth. The Sphenoidal sinus is a small irregular cavity formed in the sphenoid, ethmoid, and palatine bones. It is subdivided by inconiplete partitions into several compartments, especially into an anterior included between the plates of the palatine, and a well-marked posterior one, excavated in the pre-sphenoid bone ; the latter is separated from its fellow on the opposite side by a perforated lamella. The Ethmoidal sinus, the smallest of these cavities,- is a space included in the volute of the ethmoid bone. It communicates by a small opening with the maxillary sinus. The sinuses which contain air, and are larger in the adult than in the young animal, are partially divided by imperfect septa, which run across their interior ; in the fresh state they are lined with mucous membrane. Separate Bones of the Skull. cranial bones. The bones of the Cranium which we now proceed to describe separately, are the occipital, sphenoid, ethmoid, and Wormian bones, which are single, and the parietal, frontal, and temporal bones, arranged in pairs ; the temporal bone is, in the horse, divided into two parts, the squamosal and petrosal bones. occipital BONE. (Fig. 10. I. ; 12. 1.) This bone occupies the posterior part of the skull, and is in the young animal divisible at first into four pieces, and afterwards into two, which finally unite to form one bone ; it is very irregular, and presents an external and an internal surface and borders. The external surface may be thus described. The upper or supraoccipital portion being very much exposed, is thick and strong; it terminates superiorly in a prominent crest, the crest of the occiput, which is convex anteriorly, and gives attachment to the 46 OSTEOLOGY. complexus major muscle, and below it at the back is the occipital tuberosity, on each side of which there is a roughened depression for the attachment of the cordiform part of the ligamentum nuchse. The occipital or mastoid ridge, continuous with the squamosal bone, descends from the crest on each side, and gives attachment to various muscles. The inferior or suboccipital portion presents a little below the tuberosity, a large, oval hole, the foramen magnum, through which pass the spinal cord, the spinal acces- sory nerves, and the basilar artery ; the sides of this fora- men, the transverse diameter of which is the larger, are slightly roughened for the attachment of the long odontoid ligaments, and on each side is a large rounded prominence, the condyle, which articulates with the atlas. A large process, the basilar process (basi-occipital bone), passes forwards from the lower part of the condyles, and forms the floor of the foramen, magnum, being flattened and slightly hollowed above, but rounded below, where it gives attachment to the rectus capitis anticus major and minor muscles; it articulates with the sphenoid bone in front, and has a fissure, the basilar fissure, running along its under surface, terminating posteriorly in the foramen magnum. Two flattened styloid processes extend downwards from the sides, of the bone, and give attachment to the obliquus capitis anticus, stylo-maxillaris, and stylo-hyoideus muscles ; and between each of these processes and the condyle is a deep notch, the condyloid or stylo-condyloid notch, at the bottom of which and just in front of the condyle, is the condyloid foramen which givea passage to the twelth nerve. The internal or cerebral surface has, in the supraoccipital portion, a vaulted concavity termed the occipital cupola, which covers the cerebellum ; while the superior surface of the basilar process presents a pit, the basilar fossa, in the anterior part of which the pons varolii lies, and in the posterior part the medulla oblongata. The small foramina which enter the basilar process from within the foramen magnum are for the passage of nutrient blood-vessels. The superior border is serrated, and articulates with the parietal and the lateral borders with the petrosal bones. The occipital bone resembles a vertebra more than any other of the so-called cranial vertebrae ; in the young state it separates into an inferior or basi-occipital part, representing the centrum ; two lateral exoccipitals, representing the pedicles, laminae, &c. ; and above, the supraoccipital portion, corresponding to the. PARIETAL BONE. 47 tubercle of the neural spine. The occipital bone articulates with eight bones — the parietals, squamosals, petrosals, sphenoid, and the atlas. PARIETAL BONE. (Fig. 10. n. J 12. 2.) These bones are situated at the superior and lateral parts of the cranium, of -which they form the walls and part of the roof The parietal is a large thin bone, possessed of an external and ^n internal surface, and four borders. The external surface is convex and smooth. On each side of the sagittal suture, formed by the junction of the two parietal bones, there is a curved ridge, to which the temporalis muscle is attached ; these ridges together form an angle, the point of which joins the occipital crest. The lateral parts of this surface are roughened, to articulate with the squamosal bone. The internal surface is concave, and marked by numerous grooves and indentations, which correspond with the convolutions of the brain. A groove, termed the longitudhval groove, and generally formed by a ridge or crest, runs along the junction of the two bones, and gives lodgment to the longitudinal sinus of the dura mater ; this crest terminates posteriorly in a three-sided process, the parietal protuberance or ossific tentorium, to which, as well as to the crest, is attached the falx cerebri, a part of the dura mater which contains the above-named sinus. In front of this process the longitudinal groove ends in two transverse grooves, which lodge the transverse sinuses of the dura mater, and are continued down to the parieto-temporal conduit, a passage formed between this bone and the temporal. The posterior border of this bone is thick and denticulated, and articulates with the occipital ; the anterior' border is slightly concave and strongly serrated, articulating with the frontal bone ; the internal border is denticulated^ and united to its fellow of the opposite side, forming the saggital suture ; the exte^nial border is divided by a prominent angle into two parts, the anterior one being thin, and articulating with the squamosal, while the posterior is thicker, and articulates with the petrosal Ijone, the prominent angle or crest meeting the sphenoid bone. Sometimes the sagittal suture is interrupted or rendered bifid posteriorly by the insertion of a small bone, generally triangular 48 OSTEOLOGY. in shape, and called the os trlquetruTn, or Wormian bone ; the ossific tentorium springs from this bone when present. The parietal bone articulates with its fellow, the occipital, frontal^ squamosal, petrosal, and sphenoid — i.e., with six bones, or with, seven when the Wormian bone is present. FRONTAL BONE. (Figs. 10. IV.; 12. and 13. 3.) This bone is situated at the antero-superior part of the cranium, and the pair constitute the broad, flat part called the forehead ; their union in the centre of the forehead forms the frontal suture. Each frontal bone is irregular in shape, flat externally, smooth and concave internally, and presents external and internal surfaces and four borders. The external surface is somewhat prominent above and slightly depressed below, and has a lateral process, the external orbital, which arches downwards and slightly backwards, and bounds part of the orbital fossa ; it articulates with the zygomatic process of the squamosal bone, and is also termed the frontal arch. The foramen piercing the superior part of this process is the supra- orbital, which transmits the artery, vein, and nerve of the same name. The thin plate which extends downwards and back- wards from the external lateral border of the bone is the internal orbital i)late or jjrocess, divided by a large triangular opening closed, in the articulated state, by the orbital portion of the sphenoid; and the small notch in front of the large one forms, with the sphenoid bone, the internal orbital foramen. The pit or hollow above the larger notch lodges the lachrymal gland ; and the small depression at the base of the external orbital process is for the attachment of the greater oblique muscle of the ' eye. The slightly-depressed part behind the orbital process assists in forming the temporal fossa. The internal surface is irregularly concave, and divided into two unequal parts by a bony septum, the cranial plate, which meets the cribriform plate of the ethmoid bone. The posterior division is smooth, and marked by ridges, which correspond with the convolutions of the brain, the anterior lobe of which it covers ; a furrow for the anterior meningeal artery runs upwards from the internal orbital foramen, and close to the ethmoid bone. The continuation of the longitudinal groove of the parietal bone TEMPORAL BONE. 49 runs along the median line ; and near the inner surface of the orbital plate is a longitudinal notch, the incisura sphenoidaliSy into which the orbital portion of the sphenoid bone is received. The anterior concavities form the frontal sinus, which is separ- ated from its fellow by a prominence termed the nasal spine, on the posterior part of which is a rounded surface, which joins the crista galli process of the ethmoid bone. The posterior border is divided into two parts, both of which are denticulated, the superior part articulating with the parietal, while the inferior or descending part is overlapped by the squamosal bone. The anterior border is pointed at the frontal suture, and articulates partly with the nasal and partly with the lachrymal bone. The internal border is straight and triangular, the widest part being at the septum ; it joins its fellow. The outer and inferior border is very irregular, and articulates with the sphenoid and lachrymal bones. The frontal bone articulates with nine bones : — its fellow, the parietal, squamosal, sphenoid, ethmoid, lachrymal, nasal, palatine, and superior maxillary bones. TEMPORAL BONE. "(Fig. 12. 4, 5.) Situated at the side of the cranium, the temporal bone is divided, in the horse, into two distinct pieces, named the squamosal or squamous temporal and the petrosal or petrous temporal bones.- The Squamosal bone (Fig. 10. III.) is irregularly' oval, flattened, and slightly curved, with a strong process arching out- wards and forTvards. It has an external and an internal, or cerebral surface, and a circumferent border. The external surface is rather convex, presenting numerous small foramina, which lead into the parie to-temporal conduit, a cavity between it and the parietal bone. Projecting outwards and forwards from its middle is a long, arched f process, the zygomatic, which unites with a similar process of the malar bone to form the zygomatic arch, on which the frontal arch abuts superiorly. Posterior to this abutment is a broad convex surface, which forms the inferior part of the temporal fossa ; and pro- jecting upwards from the postero-external part of the fossa is the sharp zygomatic spine. The shallow transverse concavity on the inferior face of the zygomatic process is the glenoid cavity, with .which the condyle of the lower jaw articulates ; and continuous £ 50 OSTEOLOGY. with this cavity, anteriorly, is an articular ridge, the condyle, which also forms part of the articulation, and posteriorly the anterior mastoid process, which limits the motion of the articu- lation ; the opening of the parieto-temjjoral conduit or canal is at the base of the process. Posteriorly, the bone divides, the inferior portion being beaked, and clasping the external auditory meatus of the petrosal bone, and the other extending backwards, to articulate with the occipital, the occipital ridge becoming continuous with the prolongation of the zygomatic spine. The internal surface is divided into two very unequal portions by a deep channel, which forms, with the parietal and petrosal bones, the temporal or parieto-temporal conduit. The posterior portion articulates with the petrosal bone, while the posterior half of the anterior and larger portion is greatly roughened and bevelled, superiorly, forming with the parietal bone the squamous suture of the skull : such of the remaining portion as forms part of the wall of the cranial cavity is marked similarly to the internal surface of the other cranial bones ; the remainder articulates with the ali-sphenoid bone. Thus the squamosal bone articulates with the petrosal, parietal, occipital, frontal, sphenoid, malar, superior and inferior maxillary bones. The Petrosal bone is the hardest bone in the skeleton, and is interesting, as it contains the essential part of the organ of hearing. It is a small, thick bone, somewhat pyramidal in shape, the base being turned downwards and a little backwards, and it is placed at the postero-lateral part of the cranium between and below the occipital, parietal, and squamosal bones. It presents four surfaces, a summit, and a base. The anterior .surface is divided into two portions, the more external part being roughened, and articulating by harmony with the parietal bone, while the inner and lesser portion is smooth, and forms the posterior part of the cavity for the greater lobe of the cerebrum. The posterior surface is triangular and rough, and articulates by harmony with the occipital bone. The external surface, also triangular, is divided into two parts, the inner articulating with the squamosal, the outer being interposed between the occipital ridge and the styloid process of the occipital bone. The internal surface, which forms the lateral boundary of the cavity for the cerebellum, is slightly concave, and presents several depressions, and anteriorly a large orifice and conduit, the internal TEMPORAL BONE. 51 ^ ILIUM. 85 sacrum, and gives attachment to the inferior sacro-iliac ligament. The iliacus muscle is attached to the venter surface. On the lower portion is a line or ridge continuous with the anterior edge or brim of the pubis ; together these form the ilio-pectineal line, which inferiorly separates the true pelvis from the false. On the inferior border of the shaft is the nutrient foramen, and in front of the acetabulum a second depression for the inner head of the rectus feraoris muscle. Below this depression is the ilio-pectineal eminence, which marks the junction of the ilium and the pubis, and gives attachment to the psoas parvus muscle. The inner part is smooth, concave, and grooved backwards and downwards for the obturator vessels Fia. 20. Left poatero-lateral view of a Horse's pelvis. 1, Anterior iliac spine ; 2, Posterior iliac spine. The iliac crest is the border joining 1 and 2 ; 3, niac shaft ; 4, The acetabulum, the large rough ridge above is the sciatic spine ; 6, Inferior ischiatic spine, posterior to which is the tuberosity. The anterior border, or crest of the ilium, lies above the sacral transverse process. It is concave above, convex below, thin in its middle, and roughened for the attachment of the longissimus dorsi and other muscles. Internally it terminates in a rounded eminence, the posterior iliac spine, which rises above the last lumbar and first sacral spines, and forms the highest part of the croup. Externally and anteriorly it terminates in the anterior iliac spine, which consists of four eminenges, two superior and two inferior, supported on a thick, strong, projecting bony plate ; these eminences give attachment to the oblique and transverse 86 OSTEOLOGY. abdominal and other muscles ; they are more developed in some horses than in others, and occasionally project so far as to form, what are termed " ragged hips." The superior or internal border extends' from the posterior spine to the ischium. It is sharp and thin above, and becomes thicker posteriorly, presenting above the acetabulum a roughened ridge, the sciatic or superior ischiatic spine, the posterior por- tion of which is formed by the ischium, and to which a large part of the sacro-sciatic ligament is attached. ISCHIUM. (PL. I. 14.) The ischium, intermediate in size between the ilium and the pubis, is a flat, irregularly quadrilateral bone, which extends from the acetabulum, and forms the posterior part of the pelvis ; it presents a body, a shaft, and a ramus. The shaft, which forms part of the sciatic spine, also joins the ilium in the acetabulum; it is rounded, and below the spine has a smooth surface over which the obturator intemus and pyri- formis tendons pass. It forms the external boundary of the obturator foramen. The body, which is nearly horizontal, is flat and smooth, and forms the posterior boundary of the obturator foramen. Inter- nally, it is roughened, and joins its fellow of the opposite side, forming the symphysis ischii ; posteriorly it is roughened for the attachment of muscles, and possesses on its external part a prominent projection, the tuberosity of the ischium, to which several muscles are attached. The ridge or spin^ below, running forwards from the tuberosity, is the inferior ischiatic spine, ■while the posterior border of the bone is formed by a thick ridge running from the tuberosity to the symphysis, forming with its fellow the ischial arch, which, in the male, supports the crura of the penis. The ramus, not well developed in the horse, is the small branch which joins the pubis, and forms part of the inter- nal boundary of the obdurator foramen, the union between the bones being usually marked by a transverse ridge. PUBIS. The pubis, which is the smallest division of the os innomiu- atum, is likewise irregular in shape, and forms with its fellow the PELVIC APERTURES. 87 antero-inferior part of the pelvis ; it consists of a body and a ramus. The hody reaches from the acetabulum to the median sym- physis ; its superior surface is concave to receive the urinary bladder, and its inferior surface is convex, and transversely crossed by a deep groove from the acetabulum, which contains the pubio-femoral ligament. The crest is the roughened anterior border, which terminates at the symphysis. The posterior border extends to the ramus, and forms the anterior margin of the obturator foramen ; at its junction with the ilium it is crossed by a groove for the obturator vessels. The outer extremity, which joins the ilium and the ischium in the acetabulum, is excavated to form the cotyloid notch. The ramus is the flattened portion which projects posteriorly, joins the ramus of the ischium, forming part of the boundary of the obturator foramen, and with its fellow the symphysis pubis internally. ACETABULUM. (Fig. 20. 4.) The cotyloid cavity or acetahulura is situated on the extero- lateral aspect of the pelvis, where the three segments of the os innominatum unite. It receives the head of the thigh-bone, andl is one of the deepest articular depressions in the body, though relatively it is much less capacious in -the horse and in quadru- peds generally than in man. It is circular in outline, and, except at its inferior median part, is surrounded' by a prominent lip of bone, which becomes thin and slightly roughened at its free surface for muscular and ligamentous attachment; its mferior border presents a large notch, the cotyloid notch, continued half-way across the articulation as the fundus acetahuli, to give attachment to the round ligament (ligamentum teres), which mainly occupies it. Although the cotyloid cavity is formed by the three segments of the os innominatum, the ilium and the ischium are generally the only parts which form its articular surface, the pubis in most cases merely helping to form the roughened notch and fundus. PELVIC APERTURES. The obturator or thyroid foramen, or foramen ovale, the largest foramen in the body, exists in each os innominatum, and 88 OSTEOLOGY. is oval in outline, its long diameter being directed downwards, backwards, and inwards. It is formed entirely by the pubis and ischium, and possesses smooth margins, and thick, except where they are formed by the pubis. The inlet, or brim of the pelvis, is bounded superiorly by the sacral promontory, laterally by the ilio-pectineal line, and inferiorly by the crest and symphysis of the pubis. The aper- ture thus defined inclines downwards and backwards, being somewhat ovoid in form. The diameters of the inlet vary according to the age and sex of the animal ; in the adult male, the verticle or sacro-pubic diameter is a little less than the trausverse. The outlet, or posterior aperture, is somewhat triangular in form, and is bounded above, at its apex, by the first coccygeal bone, laterally by the sacro-sciatic ligaments, and inferiorly, by the ischia and ischiatic spines. Its vertical diameter, from the last sacral or first coccygeal segment, to the ischiatic symphysis, is less than the transverse, taken between the ischiatic spines. The length, taken from the middle of the lateral part of the inlet to the ischiatic tuberosity, is usually about equal to the transverse diameter of the inlet. FEMALE PELVIS. The size and proportions of the pelvis differ considerably with the sex of the animal. Bearing in mind that we have referred hitherto to the pelvis of the adult male, the differences in that of the female may be thus summarised : — ^The whole structure is larger. The transverse diameters above named, in fact, the transverse measurements generally, are very large, the former exceeding the vertical diameters by a mu^h larger difference than is found in the male. The internal border of the ilium is more hollowed out, and smoother. The ischial arch is large, and it presents a concave border, tending but slightly to form an angle at the symphysis. The cotyloid cavities are wider apart than in the male, while the obturator foramina are larger and more circular in form. PELVIC LIMB. The bones of the pelvic or hind extremity are the femur, patella, tibia, and fibula ; the bones of the tarsus — viz., the astragalus, os calcis, cuboid and three cuneiform bones ; one large and two small metatarsals; three phalanges and three sesamoids. See p. 65. FEMUR. 89 FEMUR. (Fig. 21.) The OS feinoris, femur, or thigh bone, the largest, thickest, -and strongest bone in the body, belongs to the class of long or cylindrical bones, and is placed in a direction obliquely down- wards and forwards, articulating with the cotyloid cavity of the os innominatura, and also with the tibia and patella. The shaft is irregularly cylindrical, and has two surfaces and two borders. The anterior surface is smooth, prominent, and marked by a few muscular imprints. The posterior surface is flattened and expanded at its upper part, and presents, towards the external part of its upper third, a circular roughened surface for the insertion of part of the triceps abductor muscle; internal to which a slight ridge runs obliquely up- wards and inwards to join the internal trochanter, to this the ischio-femoralis muscle is inserted. About its middle third is a roughened surface, for the attachment of the adductor brevis and part of the adductor longus muscles. The external border, which separates the anterior from the posterior surface, presents a prominent ridge, on the upper third of which is a sharp, flat pro- tuberance, the trochanter minor, curved forwards, and affording attachment to the gluteus externus and vastus externus muscles. At the lower third of this border is a deep, oval, roughened pit, the supra- condyloid fossa, from which the flexor perforatus muscle arises ; and about level with this, towards the inner side, is an aggregation of tubercles forming the supra-condyloid crest, where arises one portion of the gastro- cnemius muscle. The internal border, dividing the anterior from the posterior surface internally, presents near its upper third Fio. 21. Posterior view of left femur of a Horse. 1, Head ; 2, Tro- chanter major ; 3, Trochanter minor ; 4, Trochanter in temus: 5, Notch for the round liga- ment ; 6, Trochanteric fossa ; 7, 8, Places of attachment for the lateral ligaments ; 11, The condyles, separated by the intercondyloid groove ; 10, Supra-condyloid fossa. 90 OSTEOLOGY. a blunt roughened prominence, the trochanter internus. from which a ridge extends upwards to the head, and to which the psoas magnus, iliacus,. and vastus internus muscles are attached. From this trochanter another ridge, to which the pectineus muscle is inserted, runs downwards, the nutrient foramen being in its. lower part. The proximal extremity terminates in the head and the trochanter major. The head is the smooth articular portion directed upwards and inwards, and is received in the cotyloid cavity ; it is separated from the body by a constricted portion, the neck, not well marked in solipedes, and between the head and neck there is a- ridge for the attachment of the capsular ligament. The deep notch at the inner part of the head is for the attachment of the pubio-femoral and round ligaments. The trochanter major is a very large eminence, which projects out- wards and upwards, and presents posteriorly a prominent part termed the summit, wLich stands a little higher than the arti- cular head, and gives attachment to one portion of the gluteus maximus muscle, and anteriorly the convexity, which is rounded and covered externally by cartilage, over which plays another tendon of the gluteus maximus, and becomes inserted to the ridge just below. Behind the trochanter, and between it and the head, is the trochanteric or digital fossa, around and in which several small muscles are inserted ; bounding this fossa, externally is the trochanteric ridge, continuous with the posterior part of the summit of the trochanter. The distal extremity presents posteriorly two condyles, and anteriorly a trochlea ; the condyles, which articulate with the head of the tibia, are placed side by side, being separated by a deep intercondyloid groove, from which the interosseous crucial ligaments of the articulation spring, and into which the spine of the tibia projects. The external condyle has two fossae on the outside, one for the origin of the popliteus, and one for the external lateral ligament; the internal condyle has a roughened prominence on its lateral surface, for the attachment of the internal lateral ligament, the adductor magnus, and part of the adductor longus miiscles. The trochlea is the pulley-shaped part to the front of the condyles, which articulates with the patella ; it consists of two prominences divided by a groove, and it is in a line with the intercondyloid fossa. The internal prominence is the thickest TIBIA. , 91 and most pronounced, and on the side of the bone, between the external prominence and the external condyle, is a depression, in which the tendons of origin of the extensor pedis and flexor metatarsi muscles are attached. PATELLA. (Pt. I. X.) This, the knee-pan or stifle boue, is placed^ in front of the trochlea of the femur. It is very compact, its anterior surface being irregularly convex and very much roughened, for liga- mentous attachment, and its posterior surface smooth to articu- late with the trochlea of the femur, presenting two concavities divided by a ridge, the innermost being the larger, and in the fresh state enlarged still more by a projecting fibro-cartilaginous lip, or process. The superior surface of this bone is broad, uneven', and roughened, giving insertion to the group of muscles called the triceps (or quadriceps) cruralis ; the inferior smface is rough and pointed, and gives attachment to the middle straight ligament of the patella, while the lateral borders and angles have the externa] and internal straight ligaments attached. The patella is the lever bone of the stifle joint, or it may be regarded as a sesamoid bone, developed in the tendons of the attached muscles, so as to increase their power, enabling them to act at an advantageous angle. It is liable to fracture by muscular contraction, and to luxation ; in the latter case the internal lateral ligament is injured, or may by ruptured. TIBIA. (PL. I. Y.) The tibia, or leg bone, is a long bone, larger at its proximal than its distal end, situated between the femur and the astra- galus, slanting downwards and backwards. The shaft is three-sided, possessing outer, inner, and posterior surfaces, all of which are wider above than below. The outer surface, concave superiorly and convex inferior ly, is smooth, and lodges the extensor pedis muscle ; the inner surface, slightly convex from side to side, is smooth, excepting at its superior part, where it gives attachment to one tendon of the biceps rotator tibialis, the sartorius and gracilis muscles, and is covered chiefly by skin, fascia, and a strong periosteum. The posterior surface 9 2 OSTEOLOGY. the broadest of the three, presents on its superior third a triangular and rather smooth portion, to which the popliteus muscle is attached, the remaining two-thirds being strongly- marked by a number of longitudinal ridges, and giving attach- ment to the deep flexor muscles of the foot ; the nutrient foramen is in the upper third of this surface. The anterior border is rounded, and indistinctly marked, except in its upper third, where we find the prominent tibial ridge, which is curved outwards, and joins the anterior tuberosity of the proximal extremity. The external border is thick and concave above, so that with the fibula it forms the tibial arch. The internal border is also thick, and at its upper part has a small tubercle, to which the popliteus muscle is attached. The proximal extremity is-' much more • expanded than the distal, and presents two large, smooth, somewhat . undulated, articular surfaces, divided by a roughened conical process, the tibial spine, on the outer side of which is an irregular excava- tion for the insertion of one of the crucial ligaments. The semi- lunar cartilages are interposed between these surfaces and the condyles of the femur. Anteriorly a tuberosity, concave exter- nally and convex internally, joins the tibial ridge, and presents a vertical notch in front for the middle straight ligament of the patella. At the sides are two processes, to which the lateral ligaments are attached, the external being the largest, and presenting also an articular facet for the head of the fibula. Between this process and the anterior tuberosity is a deep groove, for the passage of the tendinous part of the flexor metatarsi muscle. The distal extremity, much smaller than the proximal, and flattened transversely, presents two smooth, deep articular grooves, which run obliquely backwards and inwards, the internal being the deepest, and the external the widest ; also three pro- jections, the middle one forming a division between the groves, being articular and continuous with them, while the others, which form the lateral processes or Tnalleoli, are roughened outside for the reception of ligaments. The articular surface corresponds to the trochlea of the astragalus articulating with it. The internal malleolus is the most prominent, and the external the widest, being grooved for the passage of the tendon of the peroneus muscle. ASTRAGALUS, FIBULA. (PL. L //.) This is a long slender bone, little developed in the horse, and is an appendage to the tibia, being attached to the outer side of that bone, and extending from its head to its lower third, to which it is affixed by a ligement ; the space between the two bones is called the tibial arch. The head, or superior part, is nodular, somewhat flattened, and roughened externally for the attachment of the external lateral ligament of the joint above ; internally it articulates with the external lateral part of the head of the tibia. Distally the bone becomes slender, and tapers to a point, from which a liga- ment is sometimes continued the whole length of the tibia. The peroneus muscle arises chiefly from the fibula. TARSUS. The tarsus, or hock, corresponding to the ankle-joint of a man, is composed of six irregular, compact bones, placed between the distal end of the tibia and the proximal end of the meta- tarsus ; they are arranged in two series ; one. consisting of the cuboid and three cuneiform bones, the magnum, medium, and parvum, corresponds to the lower row of carpal bones ; the other, or upper series, consists of the astragalus and calcaneum the first, forming with the bone above the mobile portion of the joint, may be said to correspond to the upper row of carpal bones, while the latter, being the lever bone, corresponds to the trapezium. These bones, like those of the carpus, are thickly covered on their articular surfaces by cartilage, which acts as a protection against concussion.' ASTRAGALUS. (Fig. 22. 2.) This, otherwise termed the os tali or ankle bone, is a pulley- like bone, placed immediately below the tibia, with which it articulates. A very large proportion of the surface of this bone is articular. The superior or supero-anterior surface presents an articular 94 OSTEOLOGY. trochlea consisting of two oblique prominences, separated by a- deep groove, directed downwards and outwards, which corres- pond to the articular surface on the distal end of the tibia. The inferior surface is concavo-convex, and excepting a small oval external portion, which rests on part of the cuboid bone, and a roughened, excavated posterior portion, in which the great inter- osseous ligament is attached, the whole of it articulates with th& superior surface of the cuneiforme magnum. The posterior surface is very irregular, and has four facets, which articulate with the calcaneum, the intervening portion being excavated and roughened. The lateral surfaces, the internal of which pre- sents a tubercle inferiorly, are roughened for the insertion of ligaments. The astra- galus articulates with the tibia and calcan- eum, the cuboid, and great cuneiform bones. CALCANEUM. (Fig. 22. L) The OS calcis or calcaneum, which forms the prominent part, termed the i-)oint of the hock, and corresponds to the heel-bone of man, is situated immediately behind the astragalus, and consists of a body and a tuberosity. The hody is the inferior por- tion, which is flattened laterally, slightly convex externally, and unevenly concave internally, both surfaces being roughened. Anteriorly it has four articular facets, which correspond to those on the astragalus, the interspaces being rough for ligamentous attachment ; posteriorly it is grooved and smooth, for the passage of the deep flexor pedis tendon ; infer- iorly it has two facets to articulate with the cuboid bone. The tuberosity is oblong, and flattened laterally, its external surface being rough ; internally it is smooth, and forms the tarsal arch, a groove covered with fibro-cartilage, in which lies the above- named flexor pedis tendon. Both borders are roughened, the posterior one being straight, and giving attachment to the calcaneo-cuboid ligament, while the anterior and shorter one is. curved. The superior extremity is expanded and roughened ; posteriorly it is covered with fibro-cartilage, over which thft Fig. 22. Bones of left tarsus of a Horse, seen from the front and outside. 1, Calcaneum ; 2, Astragalus ; 3, Cuneiforme magnum: 4, Cuneiforme med- ium : 5, Cuboid. OS CUNEIFOKME MAGNUM. 95 tendon of the flexor perforatus muscle plays ; and anteriorly is a smaller portion, also covered with cartilage, for the gastrocne- mius tendon to play over ; and, finally, a roughened depression between the two smooth portions for the insertion of the last named tendon. The calcaneum articulates with the astragalus and cuboid bones. OS CUBOIDES. (Fig. 22. 5.) The cuboid bone is a small irregularly-shaped bone, which occupies the outer part of the hock between the os calcis and the large and outer small metatarsal bones ; it presents four surfaces. The external svurface is convex, very rough and irregular, and gives attachment to ligaments ; the internal surface has four articiilar facets, the two superior of which articulate with the cuneiforme magnum, and the two inferior with the cuueiforme medium ; between the upper and lower facets a large foramen is formed by these three bones, giving passage to the perforating pedal artery. The superior surface is smooth, and possesses two continuous articular facets, one large, to articulate with the OS calcis, and the other small, to articulate with the astragalus ; the inferior surface, also smooth, has two continuous articular facets, separated by a ridge, one flat, to articulate with the large metatarsal, and the other bevelled, to articulate with the outer small metatarsal bone. The cuboid articulates with six bones — viz., the calcaneum and astragalus above, the cuneiforme magnum and medium internally, and the large and external small metatarsal bones below. OS CUNEIFORME MAGNUM. (Fig. 22. 3.) The large cuneiform, called also the scaphoid, and sometimes "the navicular bone, is the bone on which the astragalus chiefly rests ; it is somewhat flattened and thin, and presents two sur- faces and a circumferent border. The superior surface is concave and entirely articulatory, with the exception of a groove which runs from its outer surface to its middle, and gives attachment to a ligament ; this surface articulates with the astragalus. The 96 OSTEOLOGY. inferior surface is slightly convex, and presents three articular facets, two of them, separated by a rough excavation, articulating with the cuneiforme medium, while the third is small, and articulates with the cuneiforme parvum behind. The anterior and internal lateral borders are rough, for ligamentous attach- ment; the external lateral border has two facets, which articulate with the cuboid, the intervening portion being roughened. The posterior border, the smallest, is irregular, and gives attachment to ligaments. The large cunei- form bone articulates with the astragalus, the cuboid, mediunv and small cuneiform bones.' OS CUNEIFORME MEDIUM. (Fig. 22. 4.) The median cuneiform bone is somewhat flattened and tri- angular in shape, and a little smaller than the magnum, under- neath which it is placed. The superior surface is con- cave, and presents two articular surfaces for the magnum, with a roughened transverse space between. The inferior surface is convex, and rests on, and articulates with, the large meta- tarsal bone. The anterior border is rough, for ligaments ; the external lateral border has two facets for articulation with the cuboid, with a roughened depres- lateral border has one very small Fig. 2a. External view of bones of left tarsus, meta- tarsus, and digit of a Horse. 1, Distal end of tibia ; 2, Calcaneum ; 3, Astragalus ; 4, Cuboid ; 5, Cuneiforme magnum ; 6, Cunei- forme medium ; 7, Great metatarsal : 8, Exter- nal small metatarsal (splint); 9, Proximal phalanx (os suffraginis) ; 10, Sesamoids; 11, Median phclanx (os coronas); 12, Distal phalanx (os pedis); 14, Third Sesamoid (os naviculare) ; 15, Basilar process. sion between : the internal OS METATARSI MAGNUM. 97 facet, which articulates with the cuneiforme parvum, the remain- ing portion being excavated and roughened. The middle cuneiform articulates with the large and small cuneiform, the cuboid, and the large metatarsal bones. OS CUNEIFORME PARVUM. The small cuneiform is a very irregular bone, and the smallest in the hock, at the postero- internal part of which it is situated. It is sometimes divided into two parts, and presents four surfaces and two extremities. Its superior surface is smooth and concave, to articulate with the magnum ; and its inferior surface has usually two small facets, one articulating with the inner small metatarsal, the other with botb the inner and large metatarsal bones. The anterior extremity presents a very small facet for the cuneiforme medium, the remainder of the bone being very irregular, and roughened for ligaments. The small cuneiform articulates with the large and middle cuneiforms, and the large and inner small metatarsal bones. Metatarsus, os metatarsi magnum. ^FiG. 24.) This bone presents the same general appear- ance as the large metacarpal bone, from which it differs principally in being about one-sixth longer, flattened laterally, and rounded and more pro- minent anteriorly. It has three articular facets on its superior surface, a large one in the middle for the middle cuneiform, one on the inner side for the small cuneiform, and one on the outer side for the cuboid bones ; this surface also presents a deep, rough fossa of insertion in its centre. The deep groove which passes obliquely backwards and downwards,^ on the external side of this bone, is for the passage of the great meta- tarsal artery. The inferior extremity is larger and thicker than the superior. Posterior view of left metatarsus of a. Horse. 1, Large me- tatarsal bone ; 2, In- ternal, and 3, exter- nal, small metatarsal bones ; 4, Partial origin of suspensory and check-ligaments; 5, Nutrient foramen; 6, Articular ridge joining the condyles. 98 COMPARATIVE OSTEOLOGY. OSSA METATABSI PARVA. (Fig. 24. 2, 3.) These also present the same general form «*«? ihe small meta- carpal bones ; the external is the longest and largest, and has the largest head, with two facets which articulate with the cuboid bone ; the internal one has also three articular facets, two for the small, and one for the middle cuneiform bones. The two lateral facets on each head articulate with corresponding ones on the large metatarsal bone. The remaining bones of the hind extremity — viz., the three phalanges, with their three small accessory bones, so closely resemble the corresponding bones of the fore extremity, that it seems at first sight difficult to distinguish the one from the other ; the chief differences being, that the first phalanx of the hind extremity is longer, its proximal end larger, and its distal end smaller, than in the fore extremity. The second phalanx is longer, but not so broad transversely, and the third is more pointed, or semi-eliptical, in front, and more concave on its under surface, air these differences being more or less marked in degree. The three sesamoid bones are almost identical COMPAKATIVE OSTEOLOGY. In this section of the subject we shall endeavour to point out where the skele- tons of the domesticated animals, other than the horse, differ from the typical skeleton of the latter in any important particular. The following descriptions are therefore in all cases comparisons, where comparison is possible, between the typical skeleton and the skeleton in question. RUMINANTIA. In this class we take the Ox as the animal which represent? best- for oui purpose, the family Cavicornia or Bovidfe. Axial Skeleton, the skull. In the cranium of the ox an important feature is the development of the frontal bone, which extends from below the eyes to the back of the skull, forming the entire forehead and crest, in the middle of which is the frontal tuberosity, which is very large in hornless animals. Springing from the sides of the crest are two processes, varying in size and curvature, but corresponding RUMINANT SKELETON. 99 SKELETON OF THE OX (Ruminaniia). AxiAx Seeletok. Cranial Bone«.— Occipital, 1; b, Parietal, 2; a. Frontal, 2; c, Temporal, 2; Sphenoid, 1; JSthmoid, 1 ; Auditory ossiclss, 8. Facial Bones.— h, Nasal, 2 ; e. Lachrymal, 2 ; d, Malar, 2 ; /, Maxilla, 2 ; g, Premaxilla, 2 ; i. Inferior maxilla,, 2; Palatine, 2; Pterygoid, 2; Vomer, 1; Turbinals, 4 ; Hyoid (segments), 7. Teeth :— Incisors, 6 ; Canines, 2 ; Molars, 24. The Trunk.— k. Cervical Vertebrae, 7; I, Dorsal vertebrae, 13; m, Lumbar verteb-», 6; n, Sacrum ■ Lachrymal ; 3 Malar ; 4. Superior mazil> lary ; 5.- N'asal; 6. Premaxilla, with Incisive-openiugs. The parietal bone is transversely elongated, and recurved at its extremftie^ It V8 placed below the frontal crest, extending under and siipportipg the coresj and entering the temporal fossa to articulate with the sphenoid and temporal bones. Beneath the crest posteriorly it forms with its fellow the inter- parietal euiure. The Wormian bone exists, fused with the occipital and parietals. It is described as " wanting," by some authorities. The occipital bone is not visible when the skull is viewed superiorly, being concealed by the prominent frontal crest. It is much wider from side to side, but smaller than in the horse. It has neither crest nor tuberosity, the condyles being less prominent, but wider ; the styloid processes are shorter, but broader,, and curved inwards. The basilar process is short and thick, with a lai^e basilar groove, and two rough prominences for muscular attachmeat anteriorly ! J'he condyloid foram{na^are_double, sometimes triple.^ RUMINANTIA THE SKULL. 101' The squamosal and petrosal bones are united into a single temporal - bone. The teinporo-maxillary articulation, zygomatic process, temporal conduit^ the auditory bulla, and styloid process, are large. The zygomatic process does not articulate with the frontal bone. The foramen lacerum basis cranii is -considerably occluded by the prominence of the auditory bulla. The external £\iiditory meatus is small, and directed slightly downvvard-s. , Immediately •behind the sella turcica is a. slight and rough eminence, very' prominent in. some classes, the posterior clinoid process. ' The sphenoid has large and thin pterygoid processes, a deep sella turcica, anct a prominent olivary process. The pterygoid foramen is absent ; the foramen •lacerum basis cranii small, its place being largely occupied by the auditory bulla, but there is a large foramen ovale, for the passage of the inferior maxil- lary nerve and the spheno-spinal artery. The foramen lacerum orbitale,. foramen patheticum, and foramen rotundum are represented by an anterior common foramen. The ethmoid and its cells are well developed. It has a large volute, pro- longed forwards, forming a kind of third turbinal bone, called the olfactory cave (antre olfactif). The nasal bones are shorter, narrower, and not so firmly articulated as those of the horse. The posterior extremity is sunk in a groove in the anterior border of the frontal bone ; tlie anterior extremity presents two points with a notch between them, the central pair joining to form one ; therefore the nasal peak is trifid ; in the smaller ruminants it is usually double, , The superior maxilla is shorter but-broader, the maxillary spine being repre- sented by a rough protuberance, not continuous with the zygoma. The infra- orbital foramen is opposite the first molar tooth. The maxillary sinus is large,, and is prolonged between the two plates pf the palatine bone. There is nc alveolus anteriorly for a canine tooth. This bone does not assist in forming the palatine foramen. The premaxilla is broad ; its inferior surface is flat and destitute of alveolar cavities. There is no incisive foramen, but very large incisive openings. The premaxillse are rarely united by suture. The lachrymal bone is large, forming at the bottom of the orbit a large- lachrymal protuberance continuous with the maxillary sinus. The wall of this protuberance is thin and fragile. The lachrymal tubercle is absent. The malar bone is well developed. Posteriorly it is bifid ; the superior branch meets the orbital process of the frontal bone, and the posterior joins-, the zygomatic process of the temporal bone, behind the orbital fossa. The palatine bones are large, the part entering into the formation of the. bony palate being broad. The palatine crest is thin and elevated, being formed "by the union of the posterior borders of the palatine, pterygoid, and pterygoid , process of the sphenoid bones. . The posterior nares are very narrow, and' situated behind, not between, the superior maxillaj. The pterygoid bones are large, and usually close an opening which is left between the sphenoid and palatine bones. The superior turbinal is small, while the inferior one is largely developed. The vomer is very large, resting on the anterior half of the maxillary suture. The inferior maxilla is longer but less massive than in the horse ; the neck 3a more constricted, and the symphysis seldom becomes completely ossified^ 103 COMPARATIVE OSTEOLOGY There are eight small alveoli in front for the incisors and canines, the latter being close up to the former ; the condyles are small and convex in their short, but slightly concave in their long diameter, permitting considerable lateral motion to the joint. The coronoid processes are long, and the sigmoid notches very deep. The OS hyoides has a cornu and two cornicula on each side — the former (stylchyals) are suspended from the temporal bone. The spur process is small and blunt. VERTEBRA. The true vertebral column is made up of 26 segments— 7 cervical, 13 dorsal, and 6 lumbar. The bodies of the cervical vertebrae are shorter than those of the horse ; the transverse processes consist of a superior, small, and an inferior, large portion, pierced by the vertebral foramina ; the neural spines are large, and increase from before backwards ; the inferior spines unite the anterior and posterior articular ends. The atlas, smaller than that of the horse, has its alse more horizontal and slightly turned up at the external borders. The spinal foramen is large, and the posterior lateral one absent. The condyloid articulations are wide, that for the dentata being small and flat. The dentata is short, the odontoid process being broad, bounded below by a prominent articular ridge, which is not excavated in the inferior median line ; the neural spine does not bifurcate nor become continuous with the posterior articular processes. The pedicles on either side are perforated by a circular foramen. The sixth cervical vertebra has long superior spinous and transverse pro- cesses, but no inferior spine. The seventh neural spine is the longest, and points backwards and upwards; the transverse processes are single, and ter- minate in rough tuberosities ; there is no inferior sj)ine, and seldom a vertebral foramen. The centra of the dorsal vertebrae are longer than in the horse, but have the same general form ; the pedicles are almost always pierced by foramina in place of the posterior notches. The transverse processes are large, decreasing in size, and assuming an arched form from before backwards ; all but the last, or last two, present distinct articular surfaces for the costal tubercles. The neural spines are broad, long, and smooth : the five or six anterior ones incline backwards, then upwards, the remainder simply backwards ; the fourth is usually the longest, but the first four or five vary little in length. The rest gradually become shorter backwards to the last. This gives the back when viewed laterally a very different form from that of the horse. The lumbar vertebra? are longer and thicker than in the horse, their bodies being more convex on the lateral and inferior surfaces ; their transverse processes are long, the fourth being the longest, and they are almost at right angles to the body, concave anteriorly, convex posteriorly, the first four being inclined backwards; they never articulate with each other, nor does the last with the sacrum. The articular processes are small, the posterior being overlapped by the anterior ones. The sacrum is large and more arched, and the superior surface more convex than in the horse ; the spinous processes are united by more complete ossifi- cation. The superior groove is narrow and uneven, and the superior forauuna not so regular ; the under surface is more concave, the promontory being RUMINANTIA PECTORAL LIMB 103 better marked, and the inTerior foramina larger. The sacral cornua are large, aud expanded tor ligamentous attachment; the spinal canal is oval, and the convex articular portion of the body large, the articular processes being widely separated by a triangular opening leading into the canal. The transverse processes are short, thick, and non-articular anteriorly ; their external extremi- ties are bounded by a vertical border, the inferior angle of which is directed downward?, giving a deeper surface for articulation with the ilium. The coccygeal bones, from 15 to 20 in number, are strong and tuberous. Articular processes exist in the anterior ones. THORAX. Very generally the ruminants have 13 pairs of ribs, of which 8 are cnio and 5 false. They are straight, broad, long, and more uniform than tho^.a of the horse ; the superior extremity is large and smooth, the necks of the anterior ones short and thick, and the tubercles large ; the necks oi the posterior ones are long and thin, and smaller than in the horse. The angles are not well marked ; the distal extremities are expanded to articulate with their cartilages by means of true joints. The sternum is large and flattened, consisting of seven pieces, which, the anterior one excepted, unite by ossification ; and between the first segment or manubrium apd the second there is, in the larger ruminant, a true joint. The^ superior surface is concave, forming the floor of the chest, the inferior convex^, but slightly concave from side to side. The borders present between each two segments articular depressions for the costal cartilages. The cariniform cartilage is small and conical, the cnsi form large an.d circulai*. PECTORAL LIMB. The scapula is large and very triangular. The spine does not, as ;n the horse, terminate gradually in the neck, but by an abrupt angle, prolonged to a. point, the acromion process. The neck is more distinct,- and the coracoid process and glenoid cavity are both small, and placed close together. In the humerus (Fig. 25. u), the bicipital groove is single ; the external trochanter is very large, with its summit curved over the bicipital groove. The head is large, the tuberosities small, and the shaft less twisted, than in the horse. The 1-adius is short ; the ulna, longer and larger than in the horse, extends to th2 tlistal end of the radius, and articulates with the cuneiform bone. Tliere are two radio-ulnar arches, connected by a deep fissure. It is important to note here the fact that the development of the ulna, and to some extent its freedom, are directly proportional to the number of digits possessed by the animal. The carpus consists of 6 bones, 4 above and 2 .below. The upper are the scaphoid and lunar, which articulate with the radius ; the cuneiform, articulat- ing with the radius and ulna ; and the trapezium, which is small, tuberOits in fehape, and does not articulate with the radius. The lower are the os magnuM and unciform, which articulate with the large metacarpal bone, the trapezoid and pisiform bones being wanting ; the former, perhaps, is part of the os magnum. The large metacarpal bone presents a vertical groove down irs aiitgr'tr middle, which marks the original division of the bone into two. The inferior extremity is divided by a deep fissure into two articulations, each resembling 104 COMPARATIVE OSTEOLOGY.'. the single one of the horse, the external one being always the smaller ; a rudi- cpentary metacarpal is placed poslero-externally. The phalanges and sesamoids V't either limb are double, one complete set forming each digit ; they are small -Old narroW) the coffin bone resembling half of that of the horse, niesially divided. Posterior to the fetlock joint are two rudimentary digits, each con. taining two undeveloped, phalanges, the median and the distal. The OS innominatum is larger, but presents the same general appearance as in the horse. The ilium is thick, and possesses a prominent line running from the anterior spine to the superior ischiatic ridge. The internal surface is very convex, the ridge between the part resting on and that without the sacrum being well marked. The ilio-pectineal eminence is prominent, and the crest and spines very strong. The ischium equals the ilium in size ; the anterior extremity has a thick projecting e.vternal portion, which forms part of the cotyloid cavity, and is surmounted by the large superior ischiatic spine, whence a slight ridge is continued backwardb over the thick concave body to the tuber- osity. The inferior ischiatic spine is conical, pointing outwards and down- -wards. The ischial symphysis presents inferiorly a ridge and tubercle, absent in the horse. The pubis is large and concave, and the symphysis is never completely ossified. The acetabulum is deep, and the cotyloid notch is nairow and deep, being near the large foramen ovale. The inlet of the pelvic <;avity is oval; its sacro-pubic diameter is greater than the transverse one, •-•hile the sacro-ischiatic diameter of the outlet is less than the transverse. PELVIC LIMB. The femur (Fig. 25. /') is distinguished from that of the horse by the trochanter minor being wanting. The trochanter internus is a round tubercle near the posterior surface ; the head is small, but prominent, the trochanteric fossa deep, but small ; the trochanter major has only one eminence, not very prominent, and is united to the internal trochanter by a ridge. The condyles and trochlea are somewhat small, and the supracondyloid fossa is shallow.. "The patella is narrow, and somewhat conical in shape. The tibia (Fig. 25. h') has no vertical fossa on the anterior tuberosity, and no articular facet for the fibula ; the distal extremity has its external malleolus •detached, forming a small bone called the malleolar bone, which articulates ■with the tibia, calcaneura, and astragalus, and represents the distal end of the fibula, the remainder of which bone, small when present, is usually replaced "by a long ligament stretching the whole length of the tibia. The tarsiis consists of 5 bones. The astragalus is deep, but narrow, having A pulley-shaped surface inferiorly as well as superiorly. The calcaneum is lc?.«g and square ; the cuneiforme magnum and cuboid are united, forming the Cuba- cuneiform bone ; the cuneiforme medium is like that of the horse, while the parvum is very small. The large metatarsal bone has its inferior extremity divided into two equal parts by a deep fissure, with a groove superiorly. The small metatarsal bones, ■«vhen present, are rudimentary and single. The digits correspond to those of the pectoral limb. OMNIVORA — THE SKULL 10.5 VrscERAL Skeleton. In the adult Euminant, two bones are ia> (seven sterue- brae), 1 ; ffl Costal cartilages. Appendicuxar Skeleton. pectoeax limb. V, Scapula, 2 : w, Humerus, 2 ; x, Radius. 2 ; y, Ulna, 2. Carpus :—z, Trapezium. 2 ; a', Cunei- form, 2 ; 6', Lunar, 2 , &, Scaphoid, 2 ; d'. Unciform, 2 ; e', Magnum, 2 ; /', Trapezoid, 2 ; y", Pisi- form, 2. Metacarpus :—7i'. Bones, 8; Large sesamoids. 16. Digit :-i'. Proximal phalanges. 8? k'. Median phalanges, 8 ; I', Distal phalanges. 8 : I", Small sesamoids, 8. PELVIC LIMB. Pelvis.— Os Innominatum :— s. Ilium, 2 ; t, Pubis, 2 ; u, Ischium. 2. The Limb.—m', Femur, 2 ; n' , Patella. 2 ; 0', Tibia, 2 ; p'. Fibula. 2. Tarsus :- g', Calcaneum. 3 . r', Astragalus, 2 ; s'. Cuboid, 2 ; f , Cuneiforme magnum, 2 ; u', Ecto-cuneiforme. 2 ; 1/ w, Meso- and Endo-cuneiformes, 4. Metatarsus :— Large bones, 8 ; x'. Small bones, 2 ; j/'. Large Sesamoids. 16. Digit :— Proximal phalanges, 8 ; Median phalanges. 8 ; Distal phalanges. 8 ; Small sesamoids. S. Visceral Skeleton. None. The separate bones of the Skeleton of the Hog, as here considered, are 324. OMNIVOKA VERTEBRA. 107 springs the tusk ; the alveoli for the molar teeth, usually seven in number, gradually increase' in size, from the anterior one, which is very small, to the last, largely developed and strong. The maxillary sinus is small, projecting into the malar bone ; the palatine foramen opens on the palatine plate of the maxilla, before the palatine bone. The premaxilla. is large and strong ; it is not joined at the symphysis, and consequently forms no foramen incisivun^ ; its external process is very long, and articu- lates largely with the nasal bone ; there are three alvfeoli on each side for the incisor teeth. Part of the septum of the nose becomes ossified, forming the prenasal or snout bone (os rostri). The anterior nares are small and round. The imlatine bones form a large portion of the bony palate ; their orbital portion is very small. The palatine ridge is replaced by a tuberosity, with which the pterygoicT process" of the sphenoid bone articulates externally, and the pterygoid bone internally, and the union of these tliree parts results in a large trifid tubercle. The turhinals are longer and less fragile than in the horse. The inferior maxilla is very strong, having no well-defined neckj "and small interdental spaces ; the coronoid process is short, but strong, and the condyles, somewhat nodular, are compressed laterally. The dental canal terminates anteriorly by numerous small mental foramina ; and the alveoli for the molars are seven in number. Posteriorly this bone bears a certain resemblance to the corresponding human bone. The symphysis becomes' early ossified in this animal. The OS hyoides has a large body, but no appendix. The cornicula are short, while the cornua are thin, twisted somewhat like the letter S, and united to the temporal bones by elastic ligaments. FlC. 30. longitudinal Section of a Hog's Skull. 1, Os rostri; 2, Maxillary Tur. binal; 3, Frontal Turbinal ; 4, Large Ethmoidal .volute; 5, Occipital Styloid process; 6 C 6", Frontal Simis; 7, ^asal chamber: S 8', Cranial cavity; 9, Auditory bulla, VERTEBUiE, 'The true vertebral column consists of 28 vertebrae. — 7 cervical, 14 dorsal, and I 7 lumbar. The cervical vcrlcbrce are very short, convex below, and without inferior spines ; the transverse processes are bifid, and, excepting the last, the posterior ones are large and overlapping. The articular processes are strong, the anterior being pierced by a foramen entering the spinal, canal. The transverse processes are small and generally pierced by vertebral foramina. I'The atlas is strong, rough, and irregular, presenting a large tuberosity on its superior surface ; the wings are strong, particularly at their posterior borders ; 108 COMPARATIVE OSTEOLOGY. the posterior foramen is inconstant, usually openhig on the posterior edge. Tl)c axis is broad anteriorly, with a small otlontoid process, and extended articular surfaces; small transverse processes are pierced by large vertebral foramina ; the neural spine is tall and thin. Tire five posterior segments have large neural spines, the promincns especially so. There are usually 14 dorsal vertebra;, with short centra, increasing in length from before backwards. The neural spines are broad, decreasing gradually from the first backwards ; the first is nearly upright, the rest slope backwards, excepting the last two or three, whicli are slightly inclined forwards. Two^ foramina enter the neural canal on each side from the base of the transverse process. The lumbar vertebrre number 6, sometimes 7 ; their centra are longer than in any other region, resembling those of the ruminant. The neural spines are strong-pointed, and bifid at the posterior borders, the diverging laminis being continuous with the posterior oblique processes ; the transverse processes are long, nearly horizontal, and without articular surfaces ; the base of each is pierced by a small foramen leading into the neural canal The sucmm is usually made up of 4 segments ; the neural spines are very rudimentary, in fact the laminse scarcely coalesce, leaving the neural canal partly open ; the articular processes are large and overlap those of the last lumbar vertebra. The coccygeal bones vary in number, being usually from 18 to 23, and the anterior ones have articular processes. Generally there are 14 pairs of ribs— 7 true and 7 false. They are thin and ■fiat, the last three having their tubercles and the posterior part of their heads united. The second, third, fourth, and filth have true articulations distallv. The sLemum is very long, and consists usually of 7 segments, the manubrium •femaining separate as in the ox. The cariniform cartilage fortus a long eminence terminating in a blunt point. Appendicular Skeleton, pectoral limb. The scapula is large, without an acromion process ; it has a prominent spine, bearing in its centre a large tuberele, which inclines backwards over the postea-spinatus fossa. The Mimerus is short, and compressed laterally, the head inclining backwards ; the bicipital groove is single, and the external trochanter is very large, with i-ts summit curved over the bicipital groove, as in -the ox ; the external tuberosity is small, the internal one being replaced bv muscular imprints. The radius is small, and much curved ; while the ulna is a true long bone, having a xiiedullary canal, and extending to the carpus, with which it articulates. The radius and ulna are united by ligaments, which rarely become ossified. The ulna is flattened from side to side, and lies on the posterior face of the radius, in close connection, except that there exists a radio-ulnar arch. The olecranon is prominent. The carpus consists of 8 bories, 4 in the upper and 4 in the lower row. The bones of the up^jer row- are similar to those of the horse, the cuneiform articulating above wiih the ulrsa and a small portion of the radius, the lunar and scaphoid bones with the radius, but the trapezium with neither of the bones of the • forea^-m. Tlie bones of the lower row decrease from without inwards, and are the unciform, articulating with the two external, the os magnum with the large internal, and the trapezoid v»ith the small internal metacarpal bones ; the pisiform, ter- .CAENIVORA THE SKULL. 3 09 minating bluntly, does not articulate with the metacarpus, the pollex or thumb Ijeing absent. The metacarpal hones are 4 in number. The middle pair are large, the ?ide ■pair small ; the large ones articulate with each other, and with their relative ■small ones superiorly. Each terminates distally, as the single one of the horse, but the middle pair are the sole weight-carriers, for the lateral ones do •not rest upon the ground. In each of tlie four digits <;h.ere are three phalanges, Tvith their accessory sesamoid and navicular bones. PELVIS AND PELVIC LIMB- The OS innominatum presents the same general characters as that of the Tuminant ; it is, however, distinguished by the form of the ilium, which is very -conve.x on its anterior border and crest, and by the absence of the protuberance on the inferior symphysis. The femur differs tittle from that of the ox, except in its more contracted neck, which is about on a. level with the trochanter major ; the trochanter minor is wanting. The tibia resembles that of the ruminant ; its anterior tuberosity is notched, and the external malleolus is supplied by the distal end of the fibula. The fihala extends the whole len^tii of the tibia, articulating with it at both extreraitie-s and distally with the ■astragalus and calcaneum. The tarsus presents no important deviation from the typical joint, except -that the cuneiforme medium is divided, hence there ■are in the lower row the ecto, meso, and endo-cuneiform bones ; the distal articular surface of the astragalus articulates partly with the cuboid bone. The metatarsus and phalanges closely resemble those of the anterior limb. There is a very rudimentary fifth metatarsal bone on the inside, a rsstige probably of the hallux or great toe. CAENIVORA. In this order our descriptions allude mostly to the Dog, Uiat animal being an excellent type of the order, and one easily obtained. Axial Skeleton, the skull. The occipital hone of the Dog is very strong, and triangular behind, termiim^ ting in a sharp pointed crest. The tuberosity is not well marked ; the styloid processes are short, and the condyles large. The foramen lacerum basis crani? is divided into two portions by the auditory bulla, which is large aud rounded ; the basilar process is long and' thick. The Wormian bone is united to the occipital ; the ossifie tentorium is large. The parietal bones are very convex, in S'-me breeds meeting in a sharp ridge, continuous with the occipital crest. The frontal tjones are triangular, and present along their middle a hollow, moi-e or less r.'ai'ked The orbital process is simply a peak, the arch being •complet'-.d l.;p a ligament ; there is no supraorbital foramen ; the frontal bone articulates sFich the cjperior maxilla. The temporals are not divisible into distinct pieces, as in tJie horse ; the zygomatic processes are large, and -project very much, forming Capacious temporal fossse, and having glenoid ravities, which are elongated transversely, for the condyles of the inferior maxilla! 110 COMPARATIVE OSTEOLOGY. SKELETON OF THE DOG (Carnivora). AxiAx Skeleton. THE SKULL. b. Parietal, 2 : c. Frontal, 2 ; k, Temporal. 2 ;. Sphenoid, 1 ;. Cranial Bones.— a. Occipital 1 ; Ethmoid. 2 ; Auditory ossicles, 8. Facial Bones.— f, Nasal, 2 ; e, Iiachrymal, 2 ; d, Malar. 2 ; h. Maxilla. 2 ; g, Premaxilla, 2 r t, Inferior I-IaxiUa. 2 ; Palatine, 2 ; Pterygoid, 2 ; Vomer, 1 ; Turbinals, 4 ; Hyaoia series, 9. Teeth : — Incisors, 12 : Canines, 4 ; Molars, 26. Tlie Trunk.— I I, Cervical vertebrai, 7 ; m m. Dorsal vertebrse. 13 ; n n. Lumbar vertebrae, 7 \. 0, Sacrum (three segments), \ ; p p, Coccygeal vertebrae (variable), 20 ; t t, Ribs, 26 ; * Sternum (eight stemebrse), 1 ; £ Costal cartilages. Appendicular Skeleton, pectoral limb. u, Scapula, 2 ; v, Humen^s, 2 ; w, Eadius, 2 ; x, ITlna. Carpus :— j/, Trapezium, 2 ; z, Cunei- form, 2 ; a', Scaphoid, 2 ; V, Unciform, 2 ; c'. Magnum. 2 ; d' , Trapezoid, 2 ; e'. Pisiform, 2 ; Metar carpal bones, 10 ; K, Anterior sesamoids, 10 ; g' , Posterior sesamoids, 20. Digit :— i'. Proximal phalanges, 10; V, Median phalanges, 8; V, Distal phalanges, 10; Small sesamoids wanting. PELVIC LIMB. Pelvis. — Os Innominatum : — q, Ilium, 2 ; r, Pubis, 2 ; s, Ischium. 2. The Limb.—m' Femur, 2; o', Fabellje, 4; n', PateUa, 2; g'. Tibia, 2; p', Tibial sesamoid, 2; r', Fibula, 2. Tarsus :— s', Calcaneum, 2 ; <', Astragalus, 2 ; u', Cuboid, 2 ; «>', Superior cuneiform, 2 :■ w\ Ecto-cuneiforme, 2 ; x', Meso-cuneiforme, 2 ; 2/', Endo-cuneiforme, 2. Metatarsus :— Large bones, 8 ; z", Small bones, 2 ; Anterior sesamoid, 8 ; Posterior sesamoids, 16. Digit :— Proximal phalanges,. 8 ; Median phalanges, 8 ; Distal phalanges, 8 ; Small sesamoids wanting. Visceral Skeleton. Os Penis, 1 ; Eudimentary clavicle (inconstant), 2. The bones of the Carnivora Skeleton, thus considered, are 345. CARNIVORA VERTEBRA. Hit The external auditory meatus and auditory bulla are larj:;e, the sense of hearing in carnivora being very acute ; there are only diminutive hyoid, and styloid processes. There are two canals, of which there exists no trace in other domestic animals— viz., the carotid, which traverses the mastoid portion to join the venous canal between the basilar process and temporal i and another which pierces the petrous portion at the upper part of tlie carotid canal, and gives passage to the fifth pair of nerves. The sphenoid bone resemhles that of man ; its posterior part is ^liort, and presents two large wings, which mount to the temporal fossae, the anterior part being straight, and pi'olonged by small wings. The pterygoid piocesses are very short, the pituitary fossa limited by Uie clinoid processes. The ctkmoicl bone presents very deep fosste and well- developed volutes. The nasal bones are small, narrow, but wfc]er in front, presenting a semi- •circular concavity, instead of a peak. The superior maxilla is short, but strong, differing, as all the facial bones do, with the Breed; it articulates by a long process with the frontal, forms partly the socket for the canine tooth, and is spineless. The 2^^'cmaxiUa is short, and presents a small foramen incisivum, which is often wanting in the cat, alveoli for the incisors, anvhich belongs to the family Leporidse. Axial Skeleton. There are 12 dorsal, 7 lumbar, and 4 sacral vertebrae. The wing of the ctlas presents no foramina externally, but there is a very large notch in its anterior border, inside which is the cerebro-spinal foramen. As in the carnivora, there is no atlo-axoid space. The centra of the cervical vertebrce are short, broad, and strong ; while those of the dorsal region gradually increase in length backwards. The lumbar vertebrce are largely developed, AYES 115 their transverse processes, long and slender, being directed downwards and forwards ; the articular processes are almost as prominent as the neural spines, the prominent portions beiiig termed the mammillary processes (meta- pophyses), and they may be traced anteriorly into the dorsal region ; they .give attachment to portions of the longissimus dorsi muscle. The anterior costal tubercles, prolonged and sharpened, likewise afford attachment to that muscle. The sfernebrce are five in number, the presternum being very long and cariniform in shape. In the skull we note the unusual length of the zygomatic process of the malar bone, and absence of a frontal arch, which is represented by a short bifid process. The optic foramina unite to form a single passage leading from one orbital fossa to the other. The diastema and incisive openings are both very large, and laterally the superior maxilla is incompletely ossified, giving an irregular cribrated appearance to the bone ; the bony palate is exceedingly short. The auditory bulla and external meatus are well marked. The long axis of the ina,x\\la,vj condyle is placed longitudinally, and the coronoid process is very small and far below the level of the condyle, while at the angle of the jaw there is a prominent roughened ridge or spine. There are no canine teeth, and two chisel-shaped incisors exist in each jaw ; in the upper jaw of the rabbit and hare there are also two very small incisors placed immediately behind the large ones. Appendicular Skeleton. The scapula has a very large acromion process which projects backwards, arching over the postea-spinatus fossa. There is a small clavicle, but it is incomplete. The coronoid and condyloid fossae of the humerxis are connected by a foramen. The ulna is complete, reaching to the carpus, but there is no motion between it and the radius, and the extremity is therefore prone. There are five digits, one of which represents the poUex or thumb. The pelvis is broad and shallow, the ischial arch deep, and the obturator foramen large. H\\Q femur has, like that of the horse, a third or minor trochanter ; also two well-marked fabellse. The tibia and fibula are anchylosed, the former bone being very long. The astragalus resembles that of the carnivora. There are five digits, including the hallux. AVES. The scope of the present work will allow only very brief treatment of this part of the subject. We shall, therefore, merely name a few of those features in which the skeleton of the bird differs in a marked manner from the mammalian type. The vertebrae vary greatly in number, the cervical in some classes number- ing over 20, and never less than 8. Small cervical ribs exist in the young animal, which in age may become anchylosed to the vertebrae, and in the dorsal region osseous splints unite the successive transverse processes. On the posterior edge of each rib, except the first and last, is a process called the pro- cessus uncinatus, which overlaps the succeeding rib. The sternum is a single 116 COMPARATIVE OSTEOLOGY. Fia. 36. Skeleton of a Bird, o, Radius and Ulna ; h. Dorsal vertebrae : c, Sacrum and Pelvis ; g, Ploughshare bone ; k, Tibia ; i. Metatarsus : d, Furculum ; e, carina of the Sternnm; /, Distal phalanx of pectoral limb. Sternum of a Bird. A, Lateral aspect: B, Inferior aspect; r, Rostrum ; c.p. Costal process; pl.o, I'leurosteon ; c, Carina; in.x, Middle Xiphoid, process^ AVES. 117 bone presenting a very large central process posteriorly, the central xipheid process (lophosteon), outside which is a large bifurcated process (metosteon), the two projections of which are called the median and external xiphoid processes, and antero-laterally is the ridge (pleurosteon), which gives attachment to the ribs. The inferior edge of the central ridge is called the carina; often a small median spine exists anteriorly, the rostrum or presternum. The following Table shows the ntimber of vertebral segments usually found- in domesticated birds : — Rasores, Natatores, Cervical. Pigeon, . . , 12 Fowl, . :, , 14 Duck, . . . 15 Goose, . cv ^ 18 Dorsal. "t^umbo-Sacral. Coccygeal. i ' \ The costal cartilages are ossified, and thus birds are said to possess sternal and vertebral ribs. Some of the lumbar and coccygeal vertebrae become anchylosed, and assist in forming the sacrum; it is not indeed easy to define the exact points of demarcation between the lumbar, sacral, and coccygeal regions. The coccygeal bones terminate in an expanded segment, termed the Fig. 3S. Skull of & fowl. "A, Inferior aspect, the mandible being removed ; B, Lateral aspect ; px, Premaxilla; mx, Superior maxilla; p. Palatine bone; v, Vomer; j, Jugal bone; qj, Quadrato-jugal bone; I, Lachrymal; me. Median. ethn?oid ;/, Frontal ; pf, Post-fronta) process ip, Parietal ; pt. Pterygoid ; q, Os quadratum ; S2, Squamosal ; eu, Process before the Eustactdan aperture ; ho, Basi-occipital, and so, Supra-occipital bones ; ar, Articular, a, Surangular, and d, Dentary portion of the Mandible. ploughshare bone. In the skull we have to note chiefly the absence of teeth^ the existence of only one occipital condyle, and the articulation of the man- dible or lower jaw, which does not articulate directly with the skull above,, but there is interposed the quadrate bene, which, when the lower jaw is; depressed, acts on a process, the quadrato-jugal bone, connecting it with the maxilla, and so simultaneously raises the upper jaw, there being usually cl^Thti vertical motion between the latter and the cranium. 118 COMPARATIVE OSTEOLOGY. The pectoral arch consists of three parts — the scapula, clavicle, and coracoii^ bone. The scapula is sword-shaped, and placed nearly horizontally ; the ■coracoid bone, the strongest of the three, is almost perpendicular, and firmly attached to the sternum below, affording a strong basis for the bones of the wing to move upon ; it helps to form the glenoid cavity for the humeras. The clavicles project downwards and slightly forwards, arching inwards, and generally becoming united below to form a flattened plate, the hypochideum / ^he united clavicles are termed the furculum., familiarly known as the " merryw thought." The hypocleiueum is usually joined by a ligament to the sternum below ; in seme clnsses of birds it is absent ; in some the clavicles are not united ; in some, again they are united by ossification to the sternum. The ubia is larger and stronger than the radius; the carpus consists of two bones, the metacarpus of three, one of which 33 a rudimentary pollex. There are two digits, one of which has one, the other two or three phalanges. The pelvis is expanded and shield- like, -and consists of the ilium, ischium, and pubis ; but there is no inferior symphysis, and, therefore, no true pelvic cavity. The pubis is styliform, and directed backwards and inwards ; in the ostrich alone it articu- lates with its fellow. The femur is short, the tibia long, and anchylosed with Fio. 39. ^ Pectoral arch of a Bird, sc, Scapula; co, cora- eoid bone ; /, Clavicles, terminating below in the hypocleideum ; gl. Glenoid cavity. Pelvis of a Bird Acetabulum. A. Superior : B, Lateral aspect : sm, Sacrum : II, Ilium ; Is, Ischiv A.VES. IW the fibula, which is sman._ The tarsus is early fused with the metatarsus, the latter consisting generally of one long bone. The digits vary in number ; the domesticated birds usually have three anteriorly and the hallux postero-inter^ nally ; the outermost has five phalanges, the next four, the next three, while the hallux has only two. The spur, a horny projection from the metatarsus, i» sometimes counted as a digit. The bone tissue of birds is exceedingly compact and hard, and white in colour; and some of the bones are pneumatic, or contain air instead of marrow; notably these are the bones of the skull, the sternum, and the proximal bonea of the limbs. There is great variety in the amount of pneamaticity possessed by the skeleton in different species, but it is not necessarily guided by tha, Jlying power of the animal. CHAPTER II. AETHROLOGY, The several bones which form the skeleton are united by means of certain soft structures, forming a series of articulations or joints, the study of which is termed Arthrology or Syndesmology. Before considering the different forms of joints, it will be advis- able to describe briefly the various tissues, other than bone, which enter into and contribute to"^ards their formation. These are .chiefly cartilage, connective and elastic tissues, and fat. In health, one bone never comes directly in contact with another, cartilage or fibrous tissue being always interposed ; an exception to this exists in the adult skull, most of the bones of which become firmly united by ossification of the interposed soft material. CARTILAGE. Cartilage, known also by the familiar name of gristle, is a firm, bluish-white, elastic animal substance, somewhat translucent, resilient, and flexible, possessing great cohesive power. That which forms the original basis of the bony framework is termed temporary, and that which persists in the adult, pei^manent cartilage ; the former disappears as it is replaced by bone, but the latter, of which alone we have to treat here, never under normal circumstances becomes ossified. Cartilage consists of corpuscles or cells, usually imbedded in an intercellular substance or matrix. The cells, which are contained in lacunae in the matrix, are oval, round or fusiform, and nucleated, the nuclei, which appear under the microscope as small spots, containing still smaller objects called nucleoli. Cartilage when boiled yields chondrine, a substance varying slightly from gelatine. ■ There are three varieties of the permanent kind — hyaline, Jibro, and cellular cartilage. In the first, the matrix is homogen- eous, or void of definite structure, appearing slightly granular under 120 CARTILAGE. 121 the microscope. Fibro-cartilage is characterised by a matrix of fibrous tissue ; while the cellular variety consists of an aggrega- tion of cells without a matrix. Hyaline cartilage is distinguished by the following names, according to the purpose it serves : — Articular, when it encrusts the articular surfaces of bones, helping to form joints by supplying a smooth elastic cushion, which diminishes both concussion and friction ; Costal, when it supplies elastic prolongations (hsemapo- pbyses) to the ribs, connecting them distally with the sternum ; Memhraniform, when it appears as thin plates, forming per- manently open tubes, — the trachea or wind-pipe is composed of this kind of cartilage. In articular or encrusting cartilage the matrix is abundant, and the cells vary in form, those near the surface being flatter and more numerous. It is always thickest in the young, becoming thinner as the sub- jacent ossification proceeds. It is thickest in the centre of convexities, thinnest in the centre of cavities. In the adult it is non- vascular, being nour- ished by a vascular zone in the synovial membrane, called the circulus articuli vasculosus, from which the nutritive ma- terial is conveyed. The blood- vessels of the bone underneath the cartilage also assist inl supplying nourishment to the latter. All hyaline cartilage, except the articular kind, is covered by a membrane called the perichondrium. Fibro-cartilage consists of cartilage cells and fibrous tissue, which may be white or yellow, the former being tough and strong, the latter highly elastic. White fibro-cartilage is much the more plentiful, and presents the following varieties : — It ^is called Inter- articular when it appears as a pad interposed between the two articular cartilages which form a joint ; such a pad is termed a meniscus, and the temporo-maxillary and femoro-tibial joints arei furnished with such. Circumferential, where it surrounds andi •deepens an articular cavity, as the acetabulum. Connecting,) when it is interposed between bones and firmly connects them, asl Fig. 41. Section of hyaline cartilage, a, Four separating'; cells ; 6, Two cells in apposition ; c c. Nuclei ; ' d, Cavity in the matrix containing three cells. 122 ARTHROLOGY. between the vertebral ceutra. Sirat'iform or InvesHvg, wlifu it clothes the parts of bones over which the tendons of muscles phy, sometimes existing in the tendons themselves. This tissue is dullish white, opaque, and. for the most part, devoid of perichondrium i it is vascular, but its blood -vefisels are few, and confined to the fibrous tissue, which exists as inlerwoven bundles of fil)res. with ca.rtilage cells interspersed amongst them. In the variety connecting vertebrae, it consists of concentric rings of fibrous tissue, enclosing a soft elastic centre, partly made up of cartilage cells, and often regarded as the remnant of the notochord. In fishes this portion is soft and pulpy, filling the oppcjsing con- cavities of the vertebral centra. Its power of cohesion is verj* great, surpassing even that of bone. Yellow eladic fihro-cartilage is found in the epiglottis or valve, which closes the principal air-tube ; it forms part of the frame- work of the ear. and of the Eustachian tubes which convey air to the tympanum. The fibres forming the matrix are similar to those of yellow elastic tissue. Cellular or rethular cartilage is found in the *;ar of some small rodents, and in the bat. It consists of cells derisaly packed, and apparently without a matrix : the walls of the cells thus coming into contact, give it a net- like appearance, hence the name reticular cartilage, CONNECTIVE TISSUE. In one form or other this tissue is found in hW parts of the body. The chief varieties are the areolar and the fibrous ; the former serving as a connecting medium, and support to the various organs, and to the structures of which they are formed. It appears as a loose translucent mesh, its interwoven bundles form- ing spaces termed the areolae or cells, hence its name Cellular or Areolar Tissue. It consists of minute laminae and filaments mixed with small fibres of elastic tissue, while cells, or their remains, nuclei and walls, are also present, the whole embedded in a perfectly transparent basis. Other slightly varying forms, are termed Retiform, Gelatinous, &c., while the connective tissue, of the brain and retina has received the name of Neuroglia. White fibrous tissue has a similar structure to the above, but is dense, strong, and practically non-elastic. The filaments which form it are mostly parallel and wavy in their arrangement. It ADIPOSE TISSUE. 12a S'MrJ^.ii k UjjTii^-/,^k White fibrous tissue from a ligament. 65 diamrs. appears in two forms — the sheeted or aponeurotic;, which is found in investing ligaments, membranes, periosteum, &c. ; and the cordi- form, in which the fibres are col- lected in strong bundles ; this is the chief constituent of the binding ligaments, which hold articulating bones together and limit their mo- tion. The tendons of muscles are also made up mostly of this kind of tissue, but both in them and in ligaments yellow elastic fibres are also found. Connective tissue contains nerves and blood-vessels, for the supply of neighbouring structures as well as for its own nourishmeut, and also tendon cells, the latter lying in the spaces betweeu the smaller bundles. "When healthy this tissue is little sensitive to pain. YELLOW ELASTIC TISSUE. This differs from the white tissue in being yellow, elastic, and not so tough or strong. Its fibres are sometimes as large in dia- meter as 4^^Q Q in.; but when mixed with white tissue in tendons the diameter may not be more than one-sixth of this. The fibres branch and join each other, and their ends curl up when cut or broken. Acetic acid has no effect on the yellow tissue, while it causes fibres of the white to swell greatly and become quite transparent ; again, when white tissue is boUed gelatine is obtained, which is not the result of boil- ing the yellow fibres. Yellow elastic tissue is found nearly pure in the ligamentum Quchse, the tunica abdominis, the coats of the largest arteries, and elsewhere. The lungs contain a large quantity of this tissue. AriPOSE TISSUE.. Fat or adipose tissue consists of cells containing an oily material, and arranged in isolated groups, or slightly separated by meshes Fio. IS. Yellow elastic tissue, magnified, from the liga- mentum nuchas of a calf. 65 dian'rs. 124 ANTHKOLOGY. Fio. 44. Adipose tissue magnified. n a, Fat cells — those on the right in mass ; those on the left spread amongst the con- nective tissue fibree b 6. of areolar tissue and capillary blood-vessels. It is found in many parts of the body, and varies greatly in quantity ; in joints it occurs between the ligaments, and serves the purpose of a packing material, while in the form of medulla or marrow it occupies the cavities of bones. In fat cells a nucleus is rarely visible, without special preparation. LIGAMENTS. Ligaments are dense, fibrous, connecting structures. They exist in most articula- tions, and are made up principally of white fibrous tissue. There are two kinds — caijsular or bursal, and funicular or binding ligaments. Capsular ligaments are membranous structures, generally, but not always, en- closing true joints. They consist of a dense interlacement of fibres attached to bones, round the edges of the articular cartil- ages, partially or wholly surrounding the joint ; some regard them as a continuation of the periosteum. They are never closely applied, their use being to form cavities round the joints, enclosing and protecting the synovial or lubricating apparatus inside. Funicular or binding ligaments consist of rounded or flattened cords, or bands of fibrous tissue, passing from one bone to another, firmly attached to roughened portions of their surfaces. They hold the bones in their places, at the same time allowing the requisite amount of motion in the joints. Ligaments which are situated between bones are often termed interosseous. Annular ligaments are those which bind down and protect the tendons of muscles in certain joints, converting grooves in the bones into channels or tubes which are lined with synovial membrane, and through which the tendons play. Some ligaments are composed almost entirely of yellow elastic tissue, such as the ligamentum nuchae and the ligaments con- necting the vertebral arches. SYNOVIAL MEMBRANES. These are thin membranes lining the capsular or binding ligaments of true joints, or they are interposed elsewhere CLASSES OF JOINTS. 125 between structures whicli move one upon another, and which would otherwise be injured by the friction. They resemble what are termed serous membranes, in lining closed cavities, and in containing a layer of endothelial cells which secrete a a lubricating fluid, called synovia or joint-oil ; the foundation of these membranes is a layer of connective tissue, which varies ■considerably both in density and thickness. The synovial membrane terminates at the border of the articu- lar cartilage, which in the adult it never covers ; in the foetus it is said by some authorities that it . covers the cartilage also. Near the borders of articular cartilages the membrane is generally found as a projecting fold, the projection being due to a. small pad of fat, interposed between the membrane and the capsular ligament. These projections were once erroneously termed synovial glands, but their use is probably to assist in forcing the synovia between the opposing surfaces of cartilage. Under the cellular layer blood-vessels are found, and near the articular cartilage there is formed a vascular zone, the circulus articuli vasculosus, in which the capillaries terminate by dilated loops ; articular cartilage derives its nourishment partly from this source (see page 121). There are three forms of these membranes : — the capsular, which line the capsular ligaments of all true joints; bursal mem- branes, found where one structure moves upon another, as when a tendon plays over a bone, aod known as synovial hiirsce ; or, when they exist in the subcutaneous tissue, between the skin and certain prominent parts of the skeleton, they are known as hursce mucosce. The third form, %'aginal nnenihranes or sheaths, exist where one tendon forms a sheath for another, or in other canals through which tendons glide. Synovia- or joint oil, is a viscid, transparent fluid, colourless, or pale yellow, physically resembling oil, but it contains very little fatty material, consisting chiefly of albumen, salts, and water ; it is secreted by the ceils on the inner surface of the membrane. When an animal is in active exertion, there is a greater demand for joint oil than when at rest, consequently there is an increased secretion of it. CLASSES OF JOINTS. Joints may be divided into three classes — Immovable or Synarthrodial, Movable or Diarthrodial, and Mixed or Amphi- arthrodial. 126 ARTHROLOGY, SYNARTHROSIS. lu an immovable joint there is only a thin layer of fibrous or cartilaginous material interposed between the bones, the fibrous layer of the periosteum of both bones uniting to cover and become attached to the connecting material, thus serving as a ligament. If the connection is fibrous, the joint i& generally called a suture ; if cartilaginous, a synchondrosis,, These joints are found chiefly, but by no means solely, in the skull : and they tend to become obliterated, in the adult, by ossification of the connecting material. The varieties of synarthrosis are the sutura. synchondrosis, schindylesis, and goniphosis. Sutures are true or false. In the sutura vera or true suture. the contiguous margins are united by a series of interlocking processes and indentations, a thin fibrous layer being interposed, connected externally with the periosteum. Variety of shape has led to the following nomenclature : — sutura dentata, where the processes are large and tooth-like, as in the interparietal ; sutura serrata, where they are small and fine, like the teeth of a saw, as in the interfrontal ; and sutura limhosa, where the contiguous parts are dentated and also bevelled, as in the parieto-occipital — the sutura lambdoidalis of the human subject. In the false sutures, or sutura notha, the bones are joined by plain rough surfaces, of which there are two forms — sutura .squamosa, where the adjacent borders are bevelled, the edge of one bone resting on and overlapping the other, as in the parieto- temporal ; and sutura harmonia, where the articulating surfaces of two bones present no marked irregularity, as the nasal and premaxilla. Synchondrosis, as already stated, resembles a suture, but the connecting medium is cartilage instead of fibrous tissue ; examples are found in the joints between the basi-occipital and basi-sphenoid bones, and between the latter and the pre-sphenoid. Schindylesis is that form of immovable articulation, where a ridge or .plate of one bone is received into a slit or fissure in another, as the orbito-sphenoid into the incisura sphenoidalis of the frontal bone. Gomphosis is the form where one bone is inserted in a cavity or socket in another, as the teeth in the alveoli. AMPfllARTHROSIS. 127 DIARTHHOSIS. In movable or true joints the articular surface of each bone is covered by cartilage of encrustation ; the bones are held together "by ligaments, the capsular one closing the cavity of the joint, fvhich is lined by synovial membrane. In some joints there is ^ pad of fibro-cartilage interposed between the two articular 'Cartilages. Such a pad is called a meniscus, and it adds to the elasticity and freedom of the joint. Movable joluts form the most numerous ilass; they are found in the limbs and else- T^^here. The chief varieties are the arthrodia, Knarthrosis, and the ginglymus. ~ In Arthvodia the motion is slight and glid- ing, the bony surfaces being flat or slightly undulating, and the motion limited by ligaments or processes of bone, as in the small bones of the carpus and tarsus. Enarthrosis, the ball- -and-socket joint, is capable of moving in any ito-atloid stretches from a notch on Fia. 46. Neural canal of first three cervical vertebrae, opened from above to show the internal ligaments. The occiput and foramen mag- num ore seen to the right. 6, The odontoid ligament ; a, The occipito-atioid portion (long odontoid) ; c, Superior common ligament ; d, Posterior articular cavity of a vertebral centrum. the antero-inferior part of the atlas to the inferior margin of the foramen magnum ; it is thin and membranous. The capsular ligament passing completely round the joint, becomes blended with the other ligaments. The latter are sometimes considered as mere enlargements or strengthenings of the capsular ligament, which, this view being taken, would then become the only liga- ment of the joint. This joint allows of flexion, extension, circumduction, and lateral motion. Atlo-axoid Articulation. — This joint is formed by the oppo- sing articular surfaces of the atlas and axis, and is also a true joint. The atlo-axoid ligaments are the capjsular, the superior, the inferior, and the odontoid. The capsular is very broad superiorly, where it closes the atlo-axoid space. The superior ligament passes from the supero-posterior part of the ring of the atlas to the neural spine of the dentata. The inferior joins the inferior spines of the tM'O bones. The odontoid springs 132 ARTHROLOGY. from the superior part of the odontoid process, inside the ring of the atlas and may be regarded as a continuation of the superior common ligament ; it divides into two strong bands, which become attached on either side to roughened surfaces inside the neural canal of the atlas. This portion is sometimes called the short odontoid, while the long odontoid consists of smaller bands which pass forwards and are attached inside the. foramen magnum of the occipital bone ; the latter ligament is also called the occipito- axoid. The motion of this joint is purely rotatory, being in fact the rotatory joint of the head ; or, in other words, when the head rotates the atlas moves with it.' Saca^o-luwhar Articulation, — This is formed by the last lumbar and first sacral vertebrse. There are the usual typical articulations between the centra and zygapophyses, and in addition a pair of diarthroses formed by the facets on the trans- verse processes, which exist and form joints also between the fifth and sixth lumbar vertebrse (Fig. 60). The usual vertebral ligaments are found, with the addition of a pair of capsular ones for the transverse joints. Coccygeal Articulations. — These are of the typical form, but become more and more rudimentary as the bones lose more and more the true vertebral character, the discs are formed, but the ligaments become gradually blended, finally enveloping the bones in a fibrous sheath. Thoracic Articulations. The thoracic skeleton contains the articulations which unite the dorsal vertebrae to one another and to the ribs, those which connect the ribs and costal cartilages, those joining the latter to the sternum, and finally, those which connect the sternal segments. We have already described the vertebral joints. Costo-vertehral Articulation. — A diarthrodial connection is here formed by the head and tubercle of a rib, the juxtaposed facets on the bodies of two dorsal vertebrse, and the transverse process of the posterior one. The ligaments are as follows : — The stellate or radiating ligament is situated inferiorly, and consists of strong fibres, divided into three fasciculi, uniting the head of the rib, one to the vertebra in front, a second to the intervertebral disc, while the third passes to the posterior vertebra ; the interarticular or round ligament passes from the THORACIC ARTICULATIONS, 133 ridge on the head of one rib through the articulation, giving a slip to the intervertebral disc, and is attached to the fellow rib on the opposite side ; the head of the rib is thus divided into tWo distinct articulations, with capsular liga- ments and synovial sacs. Super- iorly the anterior costo-transverse unites the neck of the rib to the infero-anterior part of the vertebral transverse process, while the p)Os- terior costo-transverse passes from the supero-posterior part of the tubercle to the lateral part of' the transverse" process. One capsular ligament unites the tubercle and transverse process, eoclosing a syno- vial sac. Fig. 47. Costo-vertebral articxilation , right lateral aspect, a, Anterior, and 6, Posterior costo-transverse ligaments ; c, Ligamen- tum subflavum ; d, Interspinous, and e, Supra-spinous ligaments. Costo-vertebral articulation. Neural canal opened from above, and superior common ligament removed, a. Inter- articular ligament ; h b, Branches joining the disc. Chondro-costal Articulation. — This is a fixed joint between the rib and its cartilage ; each rib is cupped on its lower extremity, the convexity of the cartilage resting in it, and the joint, a gomphosis, is clothed around with strong fibrous tissue. Gosto-sternal Articulation. — This joint is formed by two sternal segments and a true costal cartilage. The first cartilage, however, articulates with the presternum only, and the last only with the last sternal segment. The ligaments are the capsular and the superior and inferior costo-sternal, which stretch from the costal cartilages to the sternum above and below, blending with the capsular ligament. The asternal or false cartilages are united, each free extremity becoming attached to the cartilage in front by a small elastic ligament. The first asternal cartilage is very firmly attached to the last sternal one ; a small ligament, the chondro-xi2')hoid, is also described, which connects the xiphoid and first asternal cartilages. 134 AETHROLOGY. The first pair of costo-sternal joints which are close together usually have a common capsular ligament. Sternal Articulations. — These bind together the stiernal seg- ments. The ligaments in the horse are the superior sternal, extending along the upper surface of the bones, and the intervening fibro-cartilages which eventually ossify. The cartilaginous appendages of the sternum are the cariniform and xiphoid cartilages. In the horse the former appears as a sharp ridge running from above aiid before the presternum, down the lower mesian line* of the anterior sternal segments. Its shape bears a marked resemblance to the keel and cut- water of a boat, hence its name. The xiphoid is a flat ovoid plate of cartilage attached to the posterior segment of the meso-sternum ; unlike the cariniform, its sharp edge is placed transversely. It is also called the ensiform cartilage. Articulations of the Skull. These are all sjniarthrodial, excepting the temporo-maxillary joints aud those between the hybid bone and its appendages. Collectively, the remaining joints are called the sutures of the iikuU, and some of these have received special names. SUTURES. The straight median suture extending from the occipital crest to the nasal peak is the longitudinal one, subdivided into the nasal portion, which is open at the apex, the frontal, and the saggital, the latter situated between the parietal bones, while joining the nasal and lachrymal bones to the frontal is the trans- verse suture. The coronal suture extends obliquely upwards and backward-s from the temporal fossa, between the frontal and parietal bones, while the sutura limbosa runs upwards between the parietal and occipital bones, reaching from the temporal bone to the saggital suture. For structure of sutures see page 126. TEMPORO-MAXILLARY JOINT. This articulation is a diarthrosis, and it is futnished with capsular, eocternal lateral, and posterior ligaments, and also with a meniscus or interarticular disc of cartilage. The joint AETICULATIONS OF THE HTOID SERIES. 135 is formed by the condyle of the inferior maxilla, and the condyle and glenoid cavity of the temporal bone. The meniscus is irregular and flattened from above downwards, the superior surface being concavo-convex to correspond with the condyle and glenoid cavity above ; its inferior surface being con- cave for the reception of the maxillary condyle. The capsular ligament is at- tached to the circumference of the meniscus, so forming two synovial cavities. The posteriorliga.meiii runs from the mastoid process, and the external lateral one from the zygomatic arch of the temporal bone, both going to the neck of the maxilla ; both are mere thickenings of the capsular ligament. This joint admits of lateral motion, extension, flexion, and in the herbivora elevation and depression. Fig. 49. Right temporo-maxillary articulation— external view. a, The meniscus ; b, External lateral, and c. Posterior ligaments. ARTICULATIONS OF THE HYOID SERIES. The Hyoid articulations are as follows. The temporo- hyoid articulation is amphiarthrodial, the superior angle of Fig. 50. Hyoid articulations, a, Point going to form the tem- poro-hyoid articulation ; b, Kudimentary second corni- culum ; c. Proximal, and d, Distal interhyoid articulations. the comu articulating with the hyoia process of the petrosal 136 ARTHROLOGY. bone by a piece of fibro-cartilage. The 'proximal interhyoid articulation is also amphiarthrodial, a similar cartilage joining the comu and corniculum ; the latter articulates with the hyoid bone by a true synovial joint, the distal interhyoid. In the proximal interhyoid cartilage a small ossicle may be found, which in ruminants appears as a second corniculum. The motion in the two first-named joints is considerable. We may mention here that the heel processes are attached at their ends to the thyroid cartilage of the larynx by the lateral hyo-thyroid ligaments, between which is found the middle ligament {see *' Laryngeal Ligaments "). Articulations of the Appendicular Skeleton. pectoral limb. the shoulder joint. The Scapulo-kumeral articulation is formed by the glenoid cavity of the scapula, and the articular head of the humerus. It is a baU-and-socket joint, with one strong capsular ligament The bones are held in position by the follow- ing muscles which pass from the shoulder- blade to the arm, and play the part of active ligaments : — The antea spinatus, postea spinatus, postea spinatus minor, sub- scapularis, and flexor brachii. The motion ^JtHHniHin^ of the joint is angular, lateral, and circum- ductive. THE ELBOW JOINT. The Humero-radio-ulnar is a ginglymus formed by the radius, ulna, and humerus. It has capsular and lateral ligaments. The capsular is strongest in front, where it stretches from the distal end of the humerus to the head of the radius ; posteriorly it encloses the articulation of the ulna with the humerus, and it also surrounds the double articulation between the head of the ulna and the radius. Anteriorly it is attached to the tendon of the flexor brachii, posteriorly to that of the anconeus Fig, 51. Ligaments of the elbow joint — posterior view, a, External lateral ligament ; b. Internal lateral ligament ; c, External, and d. Internal arciform ligaments. SPECIAL LIGAMENTS. 137 Tnuscle. The internal lateral ligament is crucial, longer but less, strong than the external ; it stretches from a small tubero- sity on the inner side of the internal condyle of the humerus to the head of the radius. The external lateral ligament, crucial, ishort and thick, passes from a ridge on the epitrochlea, and a cavity on its outside, to a tuberosity outside the h6ad of the radius. The joint possesses flexion and extension only. RADIO-ULNAR JOINT. This articulation, small and very firm, is formed by the articular surfaces of the radius and ulna, and consists of two true and two mixed joints. The arciform or superior radia- ting ligaments are attached on both sides to the superior part of the ulna and radius. They are curved, and blend with the lateral liga- ments of the elbow. Below the radio-ulnar arch are a few fibres, which constitute the inferior radiating ligament. The surfaces above and beneath the radio-ulnar arch are joined by the interosseous ligaments, which ossify early in life. The motion is practically nil. THE CABPUS. The ligaments of this, joint or rather group of joints, are special and common. The articulations between the bones of the upper row may be termed the superior carpal; those between the bones of the lower row the inferior carpal ; between the radius and the upper row we have the radio-carjjal ; between the upper and lower rows the hUer-carpal ; and between the lower row and the metacarpus the carpo-metacarpal. Fig. 62. Liijaments of the car- pus—anterior aspect, a, Internal lateral ligament. 6, External lateral liga- ment; c c, Anterior car- pal ligaments ; d d. Anterior carpo-metacar- pal ligaments. Special Ligaments. Superior Carpal Ligaments. — The four bones of the upper row ^re held together by three anterior and three interosseous ligaments. The anterior are flat bands placed one between each pair of bones ; and the two inner ones are covered by and 138 ARTHROLOGY. attached to the capsular ligament ; the third, the median trapezial, is covered by the external lateral ligament. The interossei are attached to the roughened grooves between the articular facets on the lateral surfaces of the scaphoid, lunar, and cuneiform bones. The two inner are blended with the anterior, while the external one is covered by the posterior common ligament. Inferior Carpal. — The bones of the lower row are held together by four ligaments, two anterior and two interos- seous. The anterior are covered, the internal one by the internal lateral, the other by the capsular ligament. The interossei are two ; the one joining the mag- num to the trapezoid is blended with the anterior ligament, but the other is separated from the corresponding anterior one by an articular facet, Radio-carjoal. — The special ligaments join- ing the radius to the upper row are three in number. The oblique one stretching obliquely from the lower extremity of the radius, under the posterior common ligament, to the scaphoid bone. A second small one, the superior tra- pezial, stretches from the external side of the inferior extremity of the radius to the superior border of the trapezium, partly covered by the external lateral ligament. A third, the smallest of all, is buried under the former, and stretches from the inferior part of the radius to the os lunare. Intercarpal. — There are three special liga- ments ; two are short, and situated under the posterior common ligaments. The first runs vertically from the scaphoid to the magnum and trapezoid, the second passes obliquely from the cuneiform to the magnum ; while the third, the inferior trapezial, by far the strongest, stretches from the trapezium to the unciform and head of the external splint bone, blending externally with the lateral, internally with the posterior common ligaments, Carpo- metacarpal. — This joint has the following special ligaments : — two anterior, two posterior, and two interosseous. The first anterior consists of two bundles uniting the os magnum to the large metacarpal bone The second anterior Fig. 53. Deep ligaments of the carpus — external view. a and 6, Deep portions of the external lateral ligament , c, Superior, d, Median and e. Inferior trapezial ligaments. COMMON CAPPAL LIGAMENTS. 139 binds the unciform to the extemal splint bone The two posterior bind the magnum and trapezoid to the large and inner metacarpal bones. The interossei unite the heads of the splint bones to the large metacarpal and bones of the lower row. Common Ligaments. The Common Ligaments are the external and internal lateral^ and the anterior and ^posterior common, or capsular. The internal lateral ligament, stronger than the external one, is slightly crucial, consisting of two bundles of fibres which cross each other; both spring from the internal side of the inferior extremity of the radius ; the superficial bundle goes to the OS magnum and large metacarpal, and the deep set to the scaphoid, trape- zoid, and inner splint bones. A part of this ligament, deep-seated also, joins the scaphoid and small metacarpal bones. The external lateral ligament also con- sists of two fasciculi, springing from the external side of the distal end of the radius ; the superficial fibres are attached to the external splint, the deep to the same, and also to the cuneiform and unciform bones. The anterior common or capsular ligament is membranous, covering the anterior portion of the carpus. This ligament is attached to the radius, the head of the large metacarpal bone,' the lateral ligaments, and to the carpal bones and their anterior ligaments. The annular ligaments are thickenings of this structure, which bind down the extensor tendons. The inner surface is smooth, and lined by synovial membrane. The posterior common ligament is one of the strongest in the body, and covers the posterior surface of the carpus, filling up the depres- sions. It passes from the distal end of the radius to the head of the large metacarpal bone, adhering to the internal lateral, median. Fig. 54. Ligaments of the carpus — postero-lntemal view, a 6, Deep portions of internal lateral liga- ment ; c, Obliqae ligament ; d. Interosseous metacarpal liga- ment; e. External Interosseous ligament of the upper row. 140 ARTHROLOGY. and inferior trapezial ligaments. Its anterior surface is attached to the two rows of bones, while its posterior is smooth, for the passage of the great flexor tendons ; the inferior carpal or cheek ligament is continuous with it. A ligamentous structure passes obliquely downwards from the posterior border of the trapezium to the large and inner metacarpal bones, completing the carpal groove or sheath for the flexor tendons; this is the posterior or investing annular liga- ment. The carpal or check ligaments, superior and inferior, will be alluded to in describing the muscles of this region. The synovial capsules are four, perhaps Jive — two small and three large. Of the latter, one is for the radius and the upper row, extending between the bones as far as the interossei; another is situated between the upper and lower rows, and a third between the lower row and metacarpus, dipping be- tween its large and small bones. There is usually a separate synovial capsule between the trapezium and cuneiform "bone, and perhaps one foj the pisiform, when present. Motion in the carpus takes place chiefly in the radio-carpal portion, to a far less degree in the intercarpal, and very slightly in the carpo-metacarpal ; the movements are flexion and extension ; very slight lateral and circumductive movements are possible. Fig. 65. Superficial ligaments of the carpus— posterior view, a. Posterior annu- lar ligament ; 6 b. Pos- terior common ligament. METAC-\RPAL ARTICULATION. This consists of diarthrodial and synarthrodial joints. The latter are furnished with interosseous ligaments, which very generally become ossified ; the articular surfaces of the former are held together partly by those carpal ligaments which sur- round them, and partly by the interosseous ligaments just named. METACARPO-PHALANGEAL ARTICULATION. This, whi'^h is popularly termed the fetlock joint, is formed by the large metacarpal bone, the proximal phalanx, and a pair METACARPO-PHALANGEAL ARTICULATION. 141 jbf sesamoids. The ligaments may be divided into those proper to the joint and the accessory. The former consist of a capsular and two lateral ones. The capsular ligament passes from the lower end of the large metacarpal bone to the head of the os suffraginis, and is attached to the lateral liga- ments, which stretch from the infero-lateral aspect of the metacarpus to the supero-lateral surface of the os suffraginis. The accessory ligaments are those imme- diately connected with the sesamoid bones. The superior sesamoidean or suspensory ligament is a long, strong band, arising posteriorly from the lower bones of the carpus and the head of the metacarpus, occupying the space between the splints. It bifurcates, and becomes attached to the summits of the sesamoids, whence the parts pass downwards and forwards, reuniting as the broad ligament, and joining the extensor pedis tendon at the antero-inferior part of the os suffraginis. Th^inferior sesamoidean liga- ments are named the external or long, the middle or short, and the internal or crucial. The external one is Y-shaped, and runs from the base of the sesamoids to the supero-posterior part of the os coronae. The middle one is V-shaped, arising from the base of the sesamoids, and it passes down to a ridge on the back of the os suffraginis. The internal one, crucial or X-shaped, likewise passes from the base of the sesamoids to the supero-posterior part of the os suffraginis, its fibres intercrossinp. The lateral sesamoidean ligaments, external and internal, are two thin layers, passing from the external surfaces of the sesa- moids to the tubercles on the head of the os suffraginis. Pos- teriorly, the sesamoid bones are connected by the interosseous Fig. 56. Sesamoidean and digi- tal ligaments— posterior aspect, a, Suspensory ligament; 6 6 6, External and middle inferior sesa- moidean ligaments. The central bundle is the Y, the two lateral ones forming the V ligament; c, Annular sesamoidean ligament; dd, Posterior ligaments of the pastern joint ; e e. Lateral, and /, Inferior, navicular ligaments. Fig. 57. Deep sesamoid, ean ligaments, a, Inter-sesamoidean ligament ; 6, Cru- cial or X liga- ment. 142 ARTEROLOGT. or intersesamoidean ligament, and covered by a pad of fibro- cartilage, which forms a smooth groove for the passage of the flexor tendons, and is converted into a canal by the annular ligament, a strong fibrous band which forms an arch posteriorly from one sesamoid bone to the other. The joint is capable of flexion and extension, with very slight lateral motion. The synovial membrane of this joint is continued upwards posteriorly, in the bifurcation of the suspensory ligament, where it forms a large cul-de-sac. " Wind-galls " are projections of this sac when it is abnormally full. PASTERN JOINT. The Proximcd interphalangeal articulation, or pastern joint, is formed by the proximal and mesian phalanges, joined by the capsulai', lateral, and two posterior ligaments. The capsular ligament extends from the articular margin of one bone to that of the other, and is adherent in front to the extensor tendon. The lateral ligaments are large and very strong, springing from the distal end of the os suffraginis and passing obliquely downwards to the postero-lateral aspect of the os coronse. The two posterior ligaments run each from three points on the sides of the os suffraginis to a piece of fibro-cartilage, described as the glenoid cartilage, and attached to the postero- superior edge of the os coronae ; between them is the insertion of the external inferior sesamoidean or Y-shaped ligament. The synovial membrane of this joint lines the glenoid cartilage and a portion of the extensor tendon, and sends upwards a sac which lies between the postero-inferior part of the first phalanx and the cartilage. The movements are flexion and extension, and, durinof flexion, some slight lateral motion. COFFIN JOINT. The Distal interphalangeal articulation, or coflSn joint, is formed by the mesian and distal phalanges and the navicular bone. Its ligaments are the capsular, antero and ]postero- lateral, and the broad, lateral, and inferior navicular. The capsular ligament includes the articulation formed by the three bones, and is attached to the extensor tendon in front and the flexor behind. The antero-lateral, which are strong and thick. THE PELVIS. 143 spring from the imprints on the lateral aspect of the os coronae, and are inserted into two depressions at the superior border of the OS pedis, partly covered by the lateral cartilages. The postero-lateral are continuations of the lateral ligaments of the pastern joint, which, after reaching the os coronse, form an elastic iibrous cord, attached to the upper border of the navicular bone, the two uniting to form the superior or hroad ligament They give off short lateral bundles to the retrossal pro- cesses and inner surfaces of the lateral carti- lages. The lateral navicular ligaments con- sist of strong white fibres, which join the angles of the navicular bone to the inner aspect of the lateral cartilages, and the wings of the os pedis. The inferior ligament is an inter- osseous one, which is attached to a roughened groove on the anterior border of the navicular bone and to the semilunar ridge of the os pedis. The synovial taemhrane lines the cavity of the joint, and sends upwards a very large sac along the posterior surface of the median phalanx. Smaller projections are found between the anterior and posterior lateral ligaments. The motion of the joint is that of flexion and extension. Fig. 58. Navicular ligaments. a a, Superior, or broad ; b. Inferior ; andc c, Late- ral ligaments. Articuiations of the Pelvic Limb, the pelvis. Bacro-iliac Articulation. — This is the articular connection hetween the axial skeleton and the pelvic limb ; it is described both as a diarthrosis and an amphiarthrosis ; it is capable of little motion, and the synovia is small in quantity, if present at all ; the joint is formed by the venter of the ilium, and the supero-lateral surface of the sacrum, which articular surfaces are clothed with cartilage, and the union completed by the three sacro-iUac liga- ments, inferior, lateral and superior. The inferior consists of strong .jundles of fibres, which envelop the articulation like a strong and irregular capsular ligament, and are attached below to the transverse process of the sacrum, and above to the venter ilii. The superior sacro-iliac, short and strong, stretches from 144 ARTHROLOGY. the spines of the sacrum to the posterior spine of the ilium. The lateral sacro-iliac is triangular, the fibres running obliqueljr Fig. 59. Sacral and peMc ligaments— left lateral aspect, a, Superior sacro-iliac liga- ment ; h, Sacral ligament ; c, Lateral sacra-iliac ligament ; d, Sacro-sciatic ligament. backwards, and it is attached above to the posterior spine and border of the ilium, below to the lateral border of the sacrum. Sacro-sciatic Ligament — This is a broad membranous expan- Fia. 60. Sacral and pelvic ligaments— inferior aspect, a. Intertransverse lumbar ligament ; b and c. Capsular ligaments of lumbar and sacro- lumbar transverse articulations ; d, Inferior sacro-iliac ligament ; e. Obturator ligament ; //, Ligament of the ischio-pubic symphysis. sion situated at the side of the pelvis, helping to form the pelvic cavity. It is attached superiorly to the lateral borders of the transverse processes of the sacrum and first two or three coccygeal HIP JOINT. 145 vertebrae ; inferiorly, to the superior ischiatic spine and tuberosity of the ischium. Between this ligament and the iliac shaft is a space, the great sciatic notch ; and a second, the lesser sciatic notch, exists between the ligament and the ischial shaft. The former gives passage to the great sciatic nerve and gluteal blood- vessels, the latter to the tendons of the obturator internus and pyriformis muscles. Some lateral bands are found joining the sacral spines to the transverse processes ; these are termed the sacral ligaments. Pelvic or Ischio-puhlc Symphysis. — This articulation is formed by the respective surfaces of the ischium and pubis, and joins the right and left ossa innominata ; in the young it consists of fibro- cartilage and white fibrous tissue, which ossify with age. The Obturator ligam,ents are thin membranes, almost closing up the obturator foramina, a small passage being left for the transit of blood-vessels. HIP JOINT. The Femoro-pelvic is a ball-and-socket or enarthrodial joint, and is formed by the acetabulum of the os innominatum and the e-rticular head of the femur. It has the following ligaments : — Ligaments of thehip joiDt — infero-internalview. a, Cotyloid ligament ; b, Round ligament; c, Pubio- femoral, crossed by the transverse ligament. The capsular, which grasps the brim of the acetabulum and roughened edge of the head of the femur ; the cotyloid, which surrounds and deepens the acetabulum ; and the transverse, which stretches over the cotyloid notch, completing the circum- L 146 ARTHROLOGY. ference of the cavity, but leaving a space for the passage of the pubio-feinoral ligament. The binding ligaments of the joint are two — the round or ligamentum teres, very short and strong, which arises from the notch in the head of the femur, and is inserted in the fundus acetabuli; the second is the pubio-femeral ligament, which arises from the head of the femur, close by the round ligament ; bound down by the transverse ligament, it passes through the cotyloid notch and along the groove on the under side of the pubis, meeting and crossing its fellow at the symphysis, and becoming con- tinuous with the abdominal fascia of the opposite side ; thus the head of the right femur is partially supported in position by the muscles of the left side, and vice versa. As it passes over the pubis, a synovial bursa is inter- posed. This ligament is peculiar to the Equidse. The motion of the joint is flexion, extension, abduction, adduc- tion, rotation, and circumduction. STIFLE JOINT. Fig. 62. Ligaments of the stifle joint — antero-internal aspect, a. Internal lateral femoro-tibial ligament ; h, In- ternal lateral patellar ligament; c, Internal, d, Middle, and «, External straight patellar ligaments. The Femoro-tibial articulation, a compound ginglymus, is formed by the trochlea and condyles of the femur, the tibia, and patella. The ligaments con- sist of two groups, the femoro-tibial and the patellar. Patellar Group. — The capsular ligament, which is attached round the trochlea of the femur, and thp articular surface of the patella, is capacious, alloAving considerable motion in the joint. The lateral ligaments, internal and external, arise from the lateral aspects of the femur, just above the condyles, and are inserted to the corresponding surfaces of the patella, the ex- ternal being the larger; they may be regarded as thickened portions of the capsular ligament. The three straight ligaments, external, middle, and internal, arise from the antero-inferior surface of the patella, and are inserted to the anterior aspect of the tuberosity of the tibia, the middle one occupying the small fossa. STIFLE JOINT. 147 At its patellar attachment, the internal straight ligament becomes enlarged, and fibro-cartilaginous in structure, projecting over the edge of the femoral trochlea, and thus enlarging the articular surface of the patella. Femoro-tlhlal Group. — There are two crescentic fibro-carti- lagiuous discs, the semilunar cartilages or "menisci, interposed between the condyles of the femur and the head of the tibia, the internal one being the larger and thinner. Their internal borders are sharp and con- cave, embracing the tibial sjDine, while the external are thick and convex. Their super- ior surfaces are hollowed for the reception of the femoral condyles, while the inferior are smooth and fiat, resting on the tibia. Their extremities terminate in the coronary ligaments, which attach them to the bones; these Sixe five in number, two for the inter- nal disc, an anterior one attaching it to an excavation in front of, while the posterior one is fixed to a furrow behind, the tibial spine. The external disc has three, one fixed in front of the tibial spine, and two behind it, of which the superior one is longer and stronger, being inserted in the intercondyloid notch of the femur, while the inferior is thin and flat, and fixed to the head of the tibia. Crucial or Iiderosseus Ligaments. — These, anterior and posterior, are very strong, and are situated between the con- dyles of the femur. The anterior or exter- nal stretches obliquely forwards, and is attached in the intercondyloid notch inside the external condyle of the femur, and to a depression on the summit of the tibial spine. The posterior or internal, the longer, arising anteriorly inside the internal condyle, crosses the anterior ligament, and is attached posteriorly to a small eminence behind the inner articu- lar surface of the head of the tibia. Lateral Ligaments. — The external one, the shorter and stronger Fio. 63. Ligaments of the stifle joint — posterior aspect, a. Exter- nal lateral patellar ligament ; 6, External lateral femoro- tibial ligament ; c, Posterior crucial ligament ; d, External meniscus ; e, Internal menis- cus ; f, Femoral coronary liga- ment ; g, Posterior external coronary ligament ; \ Fibulo- tibial ligament. 148 ARTHROLOGY. arises from the external condyle of the femur, and. passes over the head of the tibia to the fibula ; a synovial bursa lies between it and the tibia. It is separated from the capsular ligament by the tendon of origin of the popliteus. The internal lateral arises from the internal condyle of the femur, and is attached to the intero-lateral aspect of the head of the tibia. Capsular Ligament. — This name is usually applied to a mem- branous ligament enclosing the joint posteriorly, and attached to the femur, tibia, lateral ligaments, and menisci. It is by some called tho posterior ligament. Anterior to this there is a pair of membranes enclosing the joint antero-laterally. These are generally described as the synovial membranes; bat as they are considerably strengthened, and help to play the part of a capsular ligament, it may be convenient to describe them as such. There is therefore a complete capsular ligament investing the joint, thickened posteriorly. The synovial apparatus is double, each side having its own membrane, and between the two are the crucial ligaments of the joint. Anteriorly, the synovial membranes contact that of the femoro-patellar joint, and it is found that sometimes the synovial cavities are continuous with that of the latter. A large quantity of fat fills up the space between the capsules and the straight ligaments of the patella. The motions of this joint are flexion and extension, and a certain amount of rotation,, permitted by the presence of the disss. TIBIO-FIBULAR ARTICULATION. This small articulation is formed by the facets on the adjacent surfaces of the tibia and fibula, and is a diarthrodial joint. The ligaments are a strong capsular one and the interossei, which divide into superior and Inferior ; the former being a small bundle at the upper third of the fibula ; the latter consists of a membranous expansion, extending from the middle to the distal extremity of the fibula. Between the two interosseous parts pass the chief artery and vein of the region, the anterior tibial. A ligamentous cord extends downwards from the fibula to the external malleolus of the tibia, " where this cord bifurcates and unites with the two external lateral ligaments of the tarsal joint'' CRigot). Motion in this joint can hardly be said to exist. COMMON LIGAMENTS. 149^ THE TARSUS. Similar to the carpus, this, the hock joint, consists of a true or tihio-tarsal portion, together with the upper arid lower tarsal^ the intertarsal, and the tarso-metatarsal accessory articulations- The ligaments are common and special. Common Ligaments. These are the external and internal lateral and the capsular^ The internoX lateral is formed of three fasciculi of fibres, superficial, middle, and deep. The superficial, the longest and strongest, connects the internal malleolus of the tibia with the astragalus, two cuneiform, and the large and inner meta- tarsal bones. The middle fasciculus, con- sisting of two cords, likewise arises from the internal malleolus of the tibia, one division being attached to the astragalus, the other to the calcaneum. The deep fasciculus is very small; it passes from the internal malleolus to the astragalus. The external lateral ligament consists of two crucial fasciculi, superficial and deep. The superficial is strong and flat, joining the external malleolus of the tibia to the astragalus, calcaneum, cuboid, large and external metatarsal bone.. The deep fasiculus is short ; it passes obliquely backwards, arising from the external malleolus of the tibia, to the astragalus and calcaneum. The capsular ligament is very strong, and attached superiorly round the distal articular surface of the tibia, to the inferior border of the astragalus, to the cuneiforme mag- num and medium, and to the lateral and oblique ligaments ; posteriorly it is attached to .the calcaneum and astragalus, and there is a fibro-cartilaginous disc in its centre, over which glides, the flexor tendon, furnished with a synovial membrane. The capsular ligament is often described as double, and named' the anterior and posterior, the lateral ligaments with which it. blends being the lines' of division. Fio. 64. Ligaments -of the tarsus— pos- tero-internal view, a, Internal Jateral ligameuL; 6, Calcaneo- cuboid ligament. 150 ARTHROLOGY. Special Ligaments. Superior Tarsal. — These ligaments occur between the astra- galus and calcaneum, and consist of one superior, two lateral, and one interosseous. The superior stretches from the upper border of the pulley of tlie astragalus to the calcaneum; the lateral are very thin, and covered by the lateral common liga- ments ; the interosseous one is strong, occupying the greater part of the rough excavation between the articular facets of the bones. Inferior Tarsal. — The ligaments of the lower row are five, tiuo anterior, which con- nect the cuboid to the great and middle cuneiform bones, and three interosseous ones, two of v/hich correspond to the anterior ligaments ; the third interosseous ligament unites the three cuneiform bones. Some of these ligaments bound the tarsal foramen, which gives passage to the perforating pedal artery. Intertarsal. — The four ligaments in this group are of greater importance than those of the two last groups. The calcaneo-cuboid or calcaneo-metatarsal ligament stretches from the posterior border of the calcaneum to the posterior part of the cuboid, termina- ting on the head of the external metatarsal bone ; externally it reaches the lateral, in- ternally the tarso- metatarsal ligament. This ligament becomes implicated in the lesion known as curb. The Oblique, or A stragalo-metatarsal ligament, arising from the antero-internal side of the astragalus, becomes attached to the cuneiforme magnum and medium, the large metatarsal bone, and the capsular ligament, the fibres radiating from above, and running downwards and outwards. This ligament covers the seat of bone-spavin. The Tarso-metatarsal is a single strong ligament, which covers the tarsal groove and unites posteriorly all the bones of the joint to the three metatarsal bones. It is smooth, for the passage of the flexor tendon, and is the analogue of the posterior Fio. 65. Ligaments of the tarsus anterior-external view, i External lateral, and Oblique ligament. RUMINANTIA AXIAL SKELETON. 151 carpal ligament. It is pierced by the perforating pedal artery and vein, and inferiorly may be continuous with the check ligament. The great interosseous ligar)ient unites the calcaneum and astragalus to the cuboid and cuneiforme magnum, occupying the internal space formed by these bones. Annular Ligaments. — The posterior of these closes in the tarsal groove, completing the sheath for the deep flexor tendon ; hence it passes from the tuberosity and posterior border of the calcaneum to the internal ridge of the same bone, and is reflected as far down as the inner metatarsal bone. It is strengthened by a strong band which arises almost with the calcaneo- cuboid ligament. The anterior annular ligament presents three well- marked portions ; they are strong and more or less flattened bands, an inferior one passing across from the proximal end of the outer to that of the inner metatarsal bone, a middle one attached to the cuboid bone and flexor metatarsi tendon, and a superior crossing the distal end of the tibia obliquely outwards and down- wards. The three portions of this ligament bind down the terdons playing over the tarsus anteriorly. There are at least three synovial membranes, one between the astragalus and tibia, another between the rows of bones, and one also between the lower row and the metatarsus, which sends a branch upwards between the calcaneum and astragalus. The motion in the tarsal joint is in effect limited to flexion and extension, and the joint may therefore be regarded as a ginglymus. The tarsal check ligament will be described with the muscles. The metatarsal, metatarso-phalangeal, and interphalangeal joints. are like those of the anterior limb. COMPAEATIVE ARTHROLOGT. RUMINANTIA. AIIAL SKELETON. In the ox, the dorso-liunhar supraspinous ligameut is composed of yellow elastic tissue, and anteriorly is expanded, and attached to the sides rather than to the summits of the neural spines. The inferior common ligament is very strong, and the intervertebral discs thicker than those of the horse ; the ligamen- turn nuchcE is also stronger, as the weight it has to bear is greater. The sternal ribs articulate with their cartilages by means of true diarthroses, and are supplied with synovial membranes. The sternum is furnished with an inferior common ligament, and the presternum or manubrium articulates with the meso- 152 COMPAEATIVE ARTHKOLOGY. sternum by a diarthrosis of limited motion. The transverse lumbo-sacral and interlumbar axticulations, being peculiar to tbe horse, are entirely wanting here. PECTORAL LIMB. In the elbow joint the internal lateral ligament is shorter than the external. The carpus, being articulated on the same general plan as that of the horse, calls for no special description. The metacarpo -phalangeal joint is double, each digit articulating in a manner very like the single one of the horse, and^each having two lateral ligaments. The s^ispensory ligament divides into several parts inferiorly, four of which go to the sesamoid bones, one to each, either of the two external ones giving off a band which winds round to the front, and joins the tendon of the extensor proprius of the digit, while two other bands pass directly from the ligament through the interarticular notch of the metacarpus, separate and likewise join the above-named extensor tendons from the inside ; two slips pass down, unite and become attached to the small rudimentary digits or claws, afterwards separating to become united postero-superiorly to the distal phalanges ; finally, two deep branches go to the tendon of the flexor perforatus and form two rings through which passes the divided tendon of the flexor perforans. The inferior sesamoid ligaments are small, and consist of two lateral bands, which attach the sesamoid bones to the head of the proximal phalanx, and between them a very small X ligament. The intersesamoidean ligaments are three in number ; there is one between each pair of bones, and one joining the two internal ones. A common annular ligament is found about the region of the fetlocks, and two smaller special annular ligaments lower down. (Fig. 87, / g g'.) The superior interdigital ligament is crucial, and situated between the two proximal .phalanges, in small ruminants it is very rudimentary. There are only two fibrous bands which attach the glenoid cartilage to the first phalanx. The inferior interdigital ligament joins the distal phalanges and navicular bones together, and in the ox is connected with the tendon of the flexor perfo.ans. The superior navicular ligament, coming -from the mesian phalanx, is formed of elastic tissue. Pelvic Limb. The pubio-femoral ligament is wanting in all the domesticated animals other than the horse ; the absence of this ligament enables the larger ruminants to deliver those sweeping circular blows with the foot, which are known by the familiar name of "cow-kicks." There is only one stroAght ligament of the patella in the smaller ruminants. With respect to the tarsus, we may remark, that there is more motion in that joint in the ruminant, due to the greater mobility of the astragalus, which possesses gliding motion upon the calcaneum, the cubo-cuneiform bone, the tibia, and the malleolar bone, all of which assist in forming the mobile portion of the joint. In the elephant there is no roimd ligament ; and the femur instead of being, when at rest, inclined downwards and forwards, maintains an almost perpen- dicular position ; this accounts for the peculiar contour of the haunch in that animal. CARNIVORA. 153 OMNIVORA. AXIAL SKELETON. In tlie hog tlie ligamentum nuchce can scarcely be said to exist ; a fibrons cord from the dorsal spines to tbe occiput represents it. There is only one synovial capsule in the occipito-atloid joint, and there is a transverse odontoid ligament which passes over the odontoid process, and keeps it down on the floor of the atloid ring. The sternal ribs articulate disl^lly like those of the ox, and the remarks on the sternal articulations of that animal also apply to ■the hog. The temporo-maxillary joint possesses great motion anteriorly and posteriorly, resembling in its structure that of the rabbit, the anterior mastoid process being small, and the temporal articular surface large. The ligaments between the hyoid cornua and cornicula are elastic. APPENDICULAR SKELETON. The synovial membrane of the shoulder joint is continued into the bicipital groove. In the elbow joint the internal lateral ligament is shorter than the external one. The radius and ulna have been described as anchylosed and also as closely connected by fibrous tissue. Whichever be the more common mode of union, there is no motion between these bones. The four bones of the metacarpus are joined by prolongations of the great carpal liga- ments above, and below by interarticular ligaments. Each metacarpo- phalangeal joint is supplied with an intersesamoid, two lateral, a crucial inferior sesamoid, and an anterior capsular ligament, also with a synovial membrane, and lateral ligaments for the joint itself. The suspensory liga- ment is replaced by the interosseous palmar muscles, and there are small superior interdigital ligaments between the proximal phalanges. A very small osseous nodule is usually found on each of the anterior capsular ligaments of these joints. The external lateral navicular ligaments resemble those of the horse ; the internal ones are wanting. An elastic navicular ligament Like that of the ox is found in the large digits. There is no pubio-femoral and onlv one straioht vaiellar ligament. The tibio- fibular articulation consists of an amphiarthrosis superiorly, a diarthrosis inferiorly, and between these an interosseous ligament, stronger below than above. The tarsal articulation resembles iu the main that of the ruminant. CARNIVORA. AXIAL SKELETON. The ligamentum nuchce is represented by a fibrous band which is larger in the dog than in the cat ; in the cervical vertebrae of the former, and in the vertebrae generally of the latter, there are interspinous muscles instead of liga- ments. The occipito-atloid and odontoid ligaments are similar to those of the hog. In the temporo-maxillary joint there is merely ginglymoid motion, an^- the meniscus is very thin. 154 COMPARATIVE ARTHROLOGY. APPENDICTJLAK SKELETON, la the camivora the synovial membrane of shoulder joint is similar to that of the hog in its arranagement. The lateral ligaments of the elbow joint, together with the annular ligament, form a kind of ring in which the head of the radius slightly revolves, as there is a certain amount of motion between it and the ulna. The radio-ulnar articulation consists of a superior and an inferior rotatory diarthrosis, and an interosseotis ligament ; the rotatory movementB between these bones are termed pronation and supination, the prone being the normal position of the extremity. The metacarpus is formed similarly to that of the hog, but it is more mobile, and the rest of the articulations of the limb resemble those of that animal, with the exception of the distal interphalangeal, where we find anteriorly an elastic ligament which acts as the retractor of the claw, and is stronger and much more active in the cat than in the dog, the claw of the former being much more retractile. Posteriorly a piece of fibro- cartilage is the analogue of the navicular bone, which is wanting. The patella has one straight ligament, and the menisci are united. In the tibio-fibular articulation, there is superiorly a diarthrosis, otherwise it is formed on the same plan as that of the hog, as is the tarsal joint, excepting that the astragalus has an inferior head instead of a trochlea. CHAPTER III. MYOLOGY. The branch of anatomy which treats of the muscular system is called Myology. The muscles are the active organs of motion, or of locomotion, the bones and ligaments being passive organs of ^-he same. Before studying the muscles individually it is necessary to take a brief view of their anatomical and histological structure. They contain the specific contractile substance termed muscular tissue, together with areolar and fibrous tissue, and a certain amount of fatty material ; they are also furnished with nerves, blood-vessels, and absorbents. MUSCULAR TISSUE. Muscular tissue is the name applied to contractile fibres, which are either collected into bundles connected at their extremities, and forming distinct organs termed muscles, to which the familiar name flesh is applied; or they are found helping to form the walls of the hollow viscera, as the bladder, stomach, &c. In the first variety the fibre presents, when magnified, a striped appearance, the stripes being placed transversely ; it is therefore known as striped or striated fibre, and as with little exception its contraction and relaxation are controlled by the will of the animal, it is also termed voluntary fibre or muscle. The second variety differs from the first in not being striped, and also in its action being beyond the control of the will ; hence it is named non-striated or involuntary fibre. The chief exceptions to this general distinction occur in the heart and in the upper part of the oesophagus, which contain 'i-nvoluntary striated tissue. Both varieties are red in colour, but +he hue of the striated kind is far deeper. We therefore describe two kinds of muscular tissue, the striated and the non-striated. 15ft 156 MYOLOGY. STRIA.TED MUSCULAR TISSUE. Voluntary or striated muscular tiasue forms tlie mass of the so-called muscles, which terminate at either extremity in fibrous structures termed the tendons, by means of which they are attached to the bones ; the intermediate fleshy portion is often called the belly of the muscle. A muscle is composed of bundles, or fasciculi of fibres, which are the integral parts of the structure. The microscope shows these fibres to consist of fine filaments termed fihrilloe, which run parallel to each other, maintaining an undivided course throughout. Each fibre is enclosed in a delicate tubular sheath called the sarcolemma or inyolerartia, composed of a transparent and ap- parently homogeneous membrane, tough and elastic, which isolates each fibre, and frequently remains intact after rupture of its contents. The fibres, about "s^oth of an inch in diameter, are gathered into prismatic or polyhedral fasciculi, and invested with a sheath of connective tissue, which is inflected between the fibres, and called the perimysium internum ; the entire muscle has likewise an investing sheath of connective tissue, the peri- mysium externum, continuous with the above. This connective' Piu. 66. Fasciculus of striated muscu- lar fibres. Trans- verse striae seen at a; 6, Union of fibres with the tendon. Fia. 67. A single striated muscular fibre, showing its com- ponent fibriUse. tissue is membranous in structure, its use being to connect the bundles and fibres, and to serve as a matrix for the ramification of blood-vessels, nerves, and absorbents. A muscular fibre, examined under a power of 300 diameters or less, will display the transverse waving strian or lines, from which the name " striated " is derived. Longitudinal markings,. NON-STRIATED MUSCULAR TISSUE. 157 or lines are also often apparent, but are less regular than the strige. The component fibrillse of a muscular fibre may be demon- strated by macerating the tissue in strong alcohol, and pressing the prepared object, when each fibrilla will be seen to consist of a row of alternately light and dark spots. By other means, such as treatment with hydrochloric acid, or by a smart blow, a muscular fibre may be separated into transverse discs correspond- ing to its striated appearance. These two separations of a fibre have been termed the longitudinal and transverse cleavages. Could both these operations be performed on the same fibre, the result would be a crucial cleav- age of it into a number of objects which would appear under a high power as dark spots, with light spaces round them, both being rectang- ular in form ; they are known as the' sarcous elements of Botvman, and in them rests the inherent -power of contractility. Thus a trans- verse row of sarcous elements forms a disc ; ' a longitudinal row a fibrilla. When seen through the medium of the sarcolemma the dark spots appear transversely as a continuous line, hence the striated appearance of the fibre. The fig. 68. fibres cleave more readily into fibrilte than striated muscular fibres . , T from the Horse. into discs. Modern observation modifies the above, the fibre being gener- ally regarded as a series of alternate light and dark discs, the latter having on each transverse surface a number of darker granules, connected by fine longitudinal and transverse lines. The former with their nodular extremities are termed muscle-rods. A number of oval objects, related with the sarcolemma, appear on treating a fibre with acetic acid ; these are the muscle corpuscles, and they are nucleated. Striated fibres are for the most part isolated, but those of the heart, which, as already stated, are involuntary, divide into branches, and the branches of different fibres frequently join, or, as it is termed, anastomose. (Fig. 152.) NON-STRIATED MUSCULAR TISSUE. Involuntary or non-striated muscular tissue is pale in colour, and consists of fibres, bound into fasciculi by a fine perimysium of areolar tissue. The fibres never terminate in tendons, and are not invested in a sarcolemma ; they are cylindrical in > shape, and composed of 158 MYOLOGY. fusiform or elongated cells, which become apparent after macer- ation of the tissue in dilute hydrochloric acid or other reagents, or it may be without any such preparation. These cells are the contractile cells of Kolliker, and in them au elongated nucleus may be visible. The fasciculi vary very greatly in size in dif- ferent situations, and often crossing each other, they give the- tissue in some parts a mesh-like appearance. The non-striped, tissue is very abundant, being found in the walls of the ali- mentary canal and hollow viscera, in gland ducts, in the coats of blood-vessels, in the skin, and elsewhere. Both varieties of muscular tissue are plentifully supplied with blood, and in stri- ated tissue the capillaries or minute blood- vessels are arranged longitudinally with transverse connecting branches, but they do not penetrate the sarcolemma, they and the larger vessels alike being found in the perimysium or interstitial connective tissue. The striated tissue is supplied with nerves from the cerebro-spinal system, but the non- striated tissue receives its supply from the sympathetic system, and the vital stimulus conveyed by either of these causes the contraction of the fibres. The description of the arrangement of involuntary tissue forms no part of the present section of our subject ; the tissue is described here chiefly in order that its structure may be com- pared with that of the voluntary kind. TENDONS. The tendons in which voluntary muscles terminate at either end are structures resembling ligaments in their composition, being formed of white fibrous tissue mixed with yellow fibres. Like ligaments, they are practically non-elastic, and while they attach the muscles to the bones, they merely transmit the action of the former to the latter, and are therefore passive instruments of motion. The extremity of a muscle which has the most fixed attachment is called its origin ; the other extremity attached to the more movable structure, its insertion. The tendon of insertion is often longer than that of origin, which is frequently rudimentary. In some cases both extremities are equally movable. YiQ. 69. A, Non-striated muscular fibres; a a. The component fusiform cells; 6, 6, The nuclei. B and C, Single cells mora highly magnified; C having been treated with acetic acid. FASCIA. 159 The strongest part of a muscle is its point of union with the tendon, but the manner in which that union is effected is not satisfactorily explained. According to some authorities, the muscular fibres are prolonged into the connective tissue of the tendon ; or, " the contractile fibre terminates in a rounded ex- tremity which is buried in a corresponding depression in the tendon" (Chauveau). The sarcolemma and the areolar tissue, both of the fibre and tendon, are no doubt instrumental in effecting the union. Tendons often send processes into the substance of the muscle, which may extend throughout its length ; such pro- cesses are described as tendinous intersections ; they also appear to send small fibres into the substance of the bones to which they are attached. Tendons vary in form, size, and density, but all are either rounded or flattened. The former are funicular, the latter aidoneurotic tendons ; in either form their use is the same. They become attached to bones through the medium of the periosteum, sometimes expanding to strengthen its outer layer. FASCIA. Each group of muscles is invested and bound down by a strong membranous expansion of white fibrous tissue, called fascia, which is firmly connected with the bone. This ternri is however applied to other membranous expansions, differing very materially in strength, texture, and relations. For example, beloAV the skin and panniculus there is a membranous expansion, which forms a continuous covering over the whole body, composed of connective tissue more or less condensed. Hence fasciae have been divided into superficial, and deep or aponeurotic. Superficial fascia consists of cellular and elastic tissue, varying in thickness in different regions of the body. Where the skin is loose it is most distinct ; and sometimes it is inseparable from the muscles and skin, as in the eyelids and lips. Its meshes may be filled with adipose cells, or condensed so as to form a fibro-cellular membrane destitute of fat. Its use is to connect and protect the various structures it contacts, and to furnish a matrix for blood-vessels ; the fat in the subcutaneous fascia helps to conserve the animal heat, fat being a bad conductor. Aponeurotic fascia not only covers, supports, and binds down the groups of muscles, but affords processes between them, and becomes united to, and blended with, the periosteum. Some of 160 isSYOLOGY, these fasciae have distinct muscles for rendering them tense, a» the tensor fasciae latse. Fasciae are also found in connection with the walls of cavities, as in the pelvis. In the limbs, where the muscular bellies form lengthy masses, with long tendons attached at considerable distances, there would be considerable displacement during motion, were it not that in these parts the fascia is very strong, enclosing the body of each muscle in a sheath, as also each group of muscles. MUSCULAK NOMENCLATURE. Musculai" nomenclature • is unsatisfactory and confused, some muscles being named from their form, as Trapezium, Rhomboideus, Scalenus ; others from their use, as Flexor, Extensor, Adductor, Abductor, &c. ; some from their direction, as Rectus, Transversus, Obliquus ; others from their situation, as Temporalis, Peroneus, Subscapularis ; some again from their attachments, as Stemo- maxillaris, Coraco-radialis, and Stylo-hyoideus ; and some from their homologues in the human subject. A muscle may have a physiological name expressing its use, and an anatomical one alluding to some feature in its morphology ; but perhaps the most satisfactory system of nomenclature is that which names muscles from their attachments. Muscles vary so much in shape that no classification of them can be based on that feature. Some of them, however, present such marked features that certain terms are used to describe their form. Thus, biceps and triceps express a two or three-headed muscle ; a diagastric muscle has two bellies, joined by a mesian tendon ; a radiating^ muscle consists of bundles diverging from a point of attachment ; ia pen/niform muscle resembles a feather in shape, and a semipenniform one the lateral half of the same, the tendon corresponding to the axis or scapus of the feather. In the descriptions of muscles which follow, the names printed in small capitals are those most commonly in use in Great Britain, whereas the names below, and in italics, are almost uniformly anatomical, expressing in most cases the places of attachment of the muscles, — a nomenclature more valuable though less current than the one in use. CLASSIFICATION OF MUSCLES. Either an Anatomical or Physiological mode of classification can be applied to the muscular system, but the former is of course the one adopted here. Again, muscles may be classed EXPLiVNATION OF PLATE 11. Muscles of the Horse. Superficial Layer. The panniculus and tunica dbdomitialis are removed. 1. Abducens, 33. Extensor metacarpi maguus» 2. Retrahentes muscles. 34- Humeralis obliquus. 2'. AttoUens maximus. 35. Extensor pedis. 2". Attollens anticus. 36. Flexor metacarpi externus avA 3. Temporalis. medius. 4. Nasalis longus. 37. Flexor metacarpi intemus. 5. Orbicularis palpebrarum. 46. Cervical 1 47, Dorsal ] ^'^^^^^' ^^^^' 6. Levator labii superioris alseque nasi. 48, Rhomboideus longus. 7. Dilatator naris lateralis. 49, Superficialis costarum. 8. Orbicularis oris. 50, Splenius. 9. Zygomaticus. 52, lutercostales. 9'. Buccinator, 54, Tensor fasciae latoe. 10. Depressor labii inferioris. 55, Triceps abductor femoris. 11. Masseter. 56, Gluteus externus. 12. Levator humeri. 61, Biceps rotator tibialis. 13. Trapezius cervicalis. 62, Rectus femoris. 14. Trapezius dorsalis. 63. Vastus externus. 15. Latissimus dorsi. 65, Gastrocnemius 18. Pectoralis parvus. 68. Flexor pedis perforans. 19. Pectoralis magnus. 69. Peroneus. 20. Sterno-maxillaris. 70. Extensor pedis. 23. Subscapulo-byoideus. 71. Flexor metatarsi. 24. Antea-spinatus, 72. Flexor pedis accessorius. 25, Teres externus. 74. Obliquus abdominis «xtemu8» 26, Postea-spinatus. 30. Caput medium \ of the triceps 31. Caput magnum /extensor bracbii. PANNICULUS CARNOSUS. ^"■*- anatomically either according to their attachments or to the regions their fleshy portions chiefly cover. Although a nom^- clature based upon the attachments of muscles is most valuable, a descriptive classification so constructed would lead to confusion, hence we group the muscles according to the regions they mamly occupy, and divide them primarily into those covering each of the following regions : — Subcutaneous region. Head. Trunk. Pectoral limb. Pelvic limb. We shall describe them in the above order, subdividing each region as may be necessary. Muscles. subcutaneous region. panniculus carnosus. (Musculus Suhcutaneus.) After carefully removing the skin and subcutaneous cellular tissue, the first muscle which presents itself is one peculiar to quadrupeds, the Panniculus carnosus. This muscle is spread over the greater part of the body, and may be divided into facial, cervical, thoracic, and abdominal portions, but as these are con- tinuous with each other, we can conveniently describe the whole as a single structure. The panniculus, as a whole, is aponeurotic superiorly, becoming more and more fleshy as it descends. It is firmly attached to the skin by connective tissue. The facial portion consists of an aponeurotic expansion, which becomes muscular over the muscles situated below and before the zygoma. Its fibres are arranged in a divergent manner, radiating from the angle of the maxilla, and a portion is inserted to the orbicular muscle of the mouth, forming the Retractor anguli oris (Risorius Santorini). Posteriorly it unites with the cervical por- tion, which is likewise chiefly aponeurotic, commencing in iront of the neck by a thin muscular band, it joins its in fellow the median line by a fibrous raphe, and covers the muscles of the inferior cervical region. Above it becomes M 162 MYOLOGfY. aponeurotic, and is attached to the ligamentum nuchse, while infero-laterally it becomes more fleshy, and is inserted to the anterior portion of the cariniform cartilage ; some describe this portion as a part of the Levator humeri, the panniculus being firmly blended with that muscle inferiorly. The thoracic portion is continuous with the cervical at the sternum, and passes over the front of the shoulder superiorly, covering its external side ; it is attached to the dorsal spines together with the trapezius. The abdominal portion forms a broad oval-shaped fleshy expan- sion, its fibres running from the flank to the shoulder ; it is thick and fleshy behind the arm, where it has a well-marked, flat tendinous attachment to the skin, and below which a ten- dinous expansion penetrates between the chest and the limb, and is attached to the Pectoralis magnus and internal trochanter oi the humerus. Posteriorly, by a strong band, fleshy and apon- eurotic, it reaches the stifle joint and fascia of the thigh } above, it reaches the lumbar and dorsal spines, and below it becomes blended with the abdominal fascia. Relation. — It is related externally with the skin ; internally with the superficial layer of muscles. Action. — It corrugates the skin, and thus enables the animal to expel insects and irritating bodies, its use being thus protec- tive ; to some extent it also supports and binds down the subja- cent muscles. The Head. The muscles of this region may be divided into the following groups : — Anterior maxillary. Posterior maxillary. Hyoidean. Palpebral. Auricular. In addition to these we have the Glossal, Pharyngeal, and Laryngeal groups also associated with the head; the two first of these will be more appropriately described hereafter when treat- ing of the Tongue and Pharynx, and the last along with the Larynx. ANTERIOR MAXILLARY GROUP. IBS' ANTERIOR MAXILLARY GROUP. In the broad sense this group occupies the anterior half of the skull, certain of the muscles extending further backwards; it consists of the followins: muscles : — Zygomaticus. Buccinator. Orbicularis oris. Levator labii superioris alaeque Nasalis longus. [nasi. Dilatator naris lateralis. Dilatator naris transversus. Dilatator naris inferioris. Dilatator naris superioris. Depressor labii superioris. Levator labii inferioris. Depressor labii inferioris. ZYGOMATICUS. {Z ygomatico-lahialis.) (PL. XL 9.) A ribbon-shaped muscle, very pale and small, situated on the side of the face, its fibres extending forwards. Attachments. — It arises from the fascia of the masseter, near the anterior aspect of the maxillary spine, being blended with the panniculus, and is inserted near the angle of the mouth, its fibres blending with the buccinator. Action. — It retracts the angle of the mouth. BUCCINATOR. (Alveolo-Iabialls.) (Pl. II. 9'. Fig. 70. i.) Situated on the side of the face, covering the diastema and' molar teeth, this muscle is flat and thin, and consists of two layers, sometimes described as separate muscks. Attoxhments. — The internal layer arises, under the masseter, from the alveolar tuberosity, and alveoli of the molar teeth of both jaws, and blends with the orbicularis oris. The external layer exists only anteriorly, and is peuniform, its fibres being inserted along the interdental spaces. Relations. — This muscle is related superiorly with the molar glands, postero-externally with the masseter, and internally with, the buccal membrane. 164. MYOLOGY. Action. — It retracts the angle of the mouth, but specially serves to force the food between the molars, and to prevent the buccal membrane from bemg injured by the latter. ORBICULARIS ORIS. (Labialis.) (Pl. II. 8.) This is a sphincter or annular constrictor muscle, and as such has virtually neither origin nor insertion ; surrounding the mouth and forming the substance of the lips, it is separable into two layers, and is related internally with the mucous membrane of the mouth and the labial glands, and externally with the skin, to which it is firmly adherent. It is the intrinsic muscle of the lips, and receives for the most part the insertions of the extrinsic muscles. Action. — It is the constrictor of the anterior aperture of the mouth, and also assists in mastication, suction, and prehension of food. LEVATOR LABII SUPERIORIS AL^ffiQUE NASL (Supernaso-lahialis. ) (Pl. II. 6.) Situated superiorly, on the side of the cheek, running forward? and downwards, this muscle is long, flat, and aponeurotic supe- liorly, dividing into two unequal bands, between which passes the dilatator naris lateralis. Origin. — It arises from the frontal and nasal bones, the anterior division, the larger and thicker, passing under the dila- tator above named. Insertion. — To the nostril and upper lip, thfe posterior divi- sion reaching the angle of the mouth. Action. — It raises the upper lip and angle of the mouth, and dilates the nostril. NASALIS LONGUS. (Supermaxillo-Iabialis. ) (PL. II. 4. Fig. 70. g.) Situated below the preceding muscle, this muscle runs hori- zontally forwards. In shape it is pjTamidal, with a fleshy belly and a long tendon of insertion. NASAL MUSCLES. 165 Origin. — It arises from the surface of the superior maxilla, at its junction with the malar and lachrymal bones. Insertion. — The tendon passes to the extremity of thB nose, where, joining its fellow, it forms a radiating expansion, becoming lost in the upper lip. Action. — It elevates and corrugates the upper lip, if acting .with its fellow ; if acting alone, it pulls the lip to one side. Fig. 70. Muscles of tuf he<*d-Un lateral view, a, Abducens ; 6 c d, Scuto-auriculaxis externus, inferior, ^id-^Te, svBd superior portions ; e, Levator palpebrae superioris extemus; / /, O.bicuiaris palpebrarum;; g, Nasalia longus ; h. Depressor labil inferioris'; i, Buccinc^tor ; ;:, Masseter ; I, Dilatator naris lateralis ; m, Dilatator naris inferior!? ; n. Dilatator na^is superioris. DILATATOU iJ rJ.-clS LATERALIS. (Pyramidalis — Superr^uxillo-nasalis Magnus. ) (PL. II. 7. no. 70. 1.) This muscle is situated on the side of the cheek, between the branches of the levator labii superioris, extending horizontally ; it has a flat belly and tendon of origin. Attachments. — It arises from the anterior extremity of the maxillary spine ; it is inserted to the side of the nostril and the upper lip, blending with the orbicularis oris. Action. — It dilates the nostril, acting on its external wing. 166 MYOLOGr. DILATATOR. NARIS TRANSVERSALIS. (Ifaso transversalis.) Situated at the supero-anterior extremity of the nose, in front o{ the nostrils, it is single, flat, and four-sided, consisting of transverse fibres which cross each other. Origin. — The nasal peak. Insertion. — The superior surface of the cartilaginous alee of the nostrils. Action. — It dilates the nostrils. DILATATOR NARIS INFERIORIS. (Fig. 70. m.) i^Nasalis Brevis Labii Superioris — Supermaxillo-nasalis Brevis.) Another long and four-sided muscle, situated at the side of, and a little behind the nostrils. Origin. — It arises by an aponeurotic origin from the upper free margin of the superior maxilla and premaxilla. Insertion. — The skin of the false nostril. Action. — It dilates the nostril. DILATATOR NARIS SUPERIORIS. (Fig. 70. n.) Situated just above the preceding, it is broad and thin, with ttponeurotic attachments. Origin. — From the lateral surface of the free margin of the 2iasal bone. Insertion. — The skin of the false nostril. Action. — To assist the preceding muscle. DEPRESSOR LABII SUPERIORIS. Situated on the mner surface of the upper lip, covered by mucous membrane, it is thin and fleshy. Origin. — From the premaxilla at the alveoli, extending from the lateral incisors to the tushes. Insertion. — The diverging fibres pass obliquely forwards to l)lend with the upper lip and nasal cartilages. POSTERIOR MAXILLARY GROUP. 167 Action. — It compresses the upper lip, and perhaps assists in dilating the nostril. LEVATOR LABII INFERIORIS. (Levator Menti.) Situated on the inner surface of the under lip, below the mucous membrane, it is like the preceding in shape. Origin. — From the alveoli of the inferior maxilla, between the lateral incisors and tushes. Insertion. — The under lip by diverging fibres. Action. — It elevates the under lip and chin, and presses the lip on the teeth. DEPRESSOR LABII INFERIORIS. (Maxillo-labialis. ) (PL. II. 10. Fig. 70. h.) Situated along the surface of the lower jaw, it is in shape long and pyramidal. Origin. — Posteriorly, in common with the buccinator, from the alveolar tuberosity, and the superior border of the inferior maxilla, behind the molar alveoli. Insertion. — The infero-lateral part of the under lip by a flat tendon. Action.^ — To depress the under lip. Posterior Maxillary Group. The muscles constituting this group are chiefly those of. masti- cation, which act upon the temporo-maxillary joint. They are as follows : — Masseter. Temporalis. Stylo-maxillaris. Pterygoideus intemus. Pterygoideus externus. Digastricus. * [While dissecting at the Edinburgh Veterinary College in December, 1868, I was particularly struck with the action of this muscle ; its tendon subdivides in the areolar and muscular tissue of chin and posterior lip, and its action is not quite to depress the under lip, but to elevate the chin and lower lip, and thus separate the lower lip from the lower incisors. This is the opinion, I find, recorded by the late Professor Goodsir in his posthumous manuscript. — En., Mrst Edition.] 168 MASSETEE. (Zygomatico-maxillaris. ) (Pl. II. 11. Fig. 70. h) Situated on the posterior part of the cheek, of which it forms the large fleshy portion, it is broad, thick, flat, and irregularly four-sided, consisting of several layers, intersected by tendinous bands, and enclosed in a strong a,poneurosis. Origin. — From the zygoma, the spine and external surface of the superior maxilla. Insertion. — The outer surface, posterior border, and angle of the inferior maxilla. Relation. — Externally with the facial panniculus. Over its surface are distributed the facial nerves, and along its anterior border lies the parotid duct, and the facial artery and vein ; buried beneath its substance is the alveolar vein or vena varicosa. Action. — To elevate the lower jaw and close the mouth, being an important muscle in mastication. TEMPORALIS. {Temporo-maxillaris. ) (Pls. II. 3 ; III. L) Situated in the temporal fossa, which it fills, this muscle is strong and fleshy, intersected by tendon, and covered by fascia. Origin. — From the parietal ridge, and part of the occipital crest, the zygomatic process of the temporal and the external surface of the parietal bones. Insertion. — The coronoid process of the inferior maxilla. Relation. — Externally with the muscles of the ear, and the scutiform cartilage ; inferiorly with the pterygoid muscles. A pad of fat lies between it and the orbital fossa. Action. — With its fellow it assists in closing the mouth j singly it gives slight lateral motion to the lower jaw. STTLO-MAXILLARIS. (Pl. III. 1'.) Situated behind the lower jaw, it is pyramidal and fleshy. Origin. — From the styloid process of the occiput. POSTERIOR MAXILLARY GROUP. 169 Insertion. — The posterior angle and inner margin of the lower jaw. Relation. — Externally with the parotid gland; internally with the guttural pouch. Action. — It depresses the lower jaw and draws it backwards. PTERYGOIDEUS INTERNUS. {Masseter Internus — Spheno-maxillaris.) Situated on the inner surface of the lower jaw, in the maxillary space, corresponding internally to the masseter, it is strong and fleshy, with numerous tendinous intersections. Origin. — From the pterygoid process of the sphenoid bone, and the palatine ridge. Insertion. — The inner posterior border and angle of the inferior maxilla. Relation. — Posteriorly with the pterygoideus externus and temporalis; internally with the guttural pouch, the hyoid bone, and its muscles ; externally with the ramus of the maxilla and the inferior, maxillary nerve and vessels. Action. — Acting with its fellow, it raises the jaw and closes the mouth ; when acting singly, it produces lateral motion. PYTERYGOIDEUS EXTERNUS (^Part of Spheno-maxillaris.) Situated behind the preceding, on the front and inner side of the temporo-maxillary articulation, it is short, thick, and fleshy, with slight tendinous intersections. Origin. — From the ala and pterygoid process of the sphenoid bone. Insertion. — Passing backwards and downwards, it reaches a roughed depression on the inner side of the inferior maxilla, just below its condyle. Relation. — With the temporalis and the pyterygoideus inter- nus, which is below and before it. Action. — It assists the internus, and also draws the lowe^f jaw forwards, antagonising the stylo-maxillaris. 170 MYOLOGY. DIGASTRICUS. Situated along the inner surface of the lower jaw, in the maxillary space, it contains two fleshy bellies, united by a merliflii tendon. Origin. — From the styloid process of the occipital bone. Insertion. — By a diffused tendon to the inner surface of the lower jaw, towards its symphysis ; the mesian tendon plays through a groove formed by the tendon of the hyoideus magnus, at the body of the hyoid bone. The posterior belly gives off also a bundle which is inserted to the posterior border of the ramus, considerably above the angle. Action.— li elevates the hyoid bone, retracts and depresses the inferior maxilla. Hyoid EAN Group. The muscles of this group are six in number and they act chiefly upon the hyoid series of bones. Their names are as follows : — Mylo-byoideus. Gemo-hyoideus. Hyoideus magnus. Hyoideus parvus. Hyoideus transversus. Stylo-hyoideus. MYLO-HYOroEUS. Situated in the maxillary space, along the inner side of the lower jaw, it is broad, flat, and pennifbrm, and attached to a line running along the inferior maxilla, just below the alveolar pro- cesses ; extending forwards as far as the symphysis, and to the inferior surface of the body and spur process of the hyoid bone, it meets its fellow of the opposite side in the median, line. Relation. — Externally with the inferior maxilla, the digastri- cus and the lymphatic glands ; internally with the sublingual gland, Wharton's canal, the genio-hyoideus, hyo-glossus longus, genio-hyo-glossus, and the hypoglossal and lingual nerves ; posteriorly with the pterygoidei-muscles. Action. — By drawing the os hyoides upwards and forwards it elevates the tongue, forming a kind of muscular sling in which the latter or^an lies. HYOIDEAN GROUP. 171 GENIO-HYOIDEUS. (Fig. 71. e.) Covered by the preceding muscle, this is long, fusiform, and tendinous at its extremities. Origin. — From the lower jaw, near its symphysis. Insertion. — The free extremity of the spur process of the os hyoides. Relation. — Externally with the preceding muscle, superiorly ■with the genio-hyo-glossus, and internally with its fellow. ' Muscles of the maxillary space— infero-lateral view. Stractures removed from the right side. «, Genio-hyoideus ; /, Stylo-hyoideus ; g, Hyoideus magnua. Action. — It draws the os hyoides towards the anterio-inferior part of the maxillary space. HYOIDEUS MAGNUS. {Kerato-hyoideus Magnus.) (Fig. 71. g.) Situated on the outer side of the pharynx, larynx, and ;guttural pouch, behind the comu of the os hyoides and running in the same direction, it is thin, fusiform, and tendinous at either extremity. Origin. — From the postero-inferior angle of the comu of the OS hyoides. 172 MYOLOGY. Insertion. — To a small tubercle on the heel process of the os hyoides. Relation. — Externally with the pterygoid muscle ; internally with the pharynx, guttural pouch, and hypoglossal nerve; the glosso-facial artery and glosso-pharyngeal nerve pass between it and the comu. The anterior tendon forms a ring through which plays the middle tendon of digastricus. Action. — It draws the body of the os hyoides backwards ana upwards, thus antagonising the preceding muscle ; it also assists in dilating the glottis. HYOLDEUS PAEVUS. (Kerato-hyoideics Parvus.) Situated above and before the preceding muscle, it is small» flat, and triangular. Origin. — From the inferior border of the anterior extremity of the comu, and the posterior border of the comiculum. Insertion. — To the body and heel process of the os hyoides, filling up the space between the three bones. Relation. — Externally with the hyo-glossus and the lingual arteries ; internally with the mucous membrane. Action. — It approximates the three bones to which it is attached. HYOIDEUS TRANSVERSUS. A short, thin muscle, joining the comicula together by their superior extremities, which on contraction it approximates. STYLO-HYOIDEUS. (Fig. 71./.) Flat and triangular, it fills up the space between the posterior part of the angle of the comu, and the styloid process of the occipital bone. Origin. — The anterior border of the styloid process. Insertion. — The posterior part of the comu. Relation. — Externally with the parotid gland, and internally with the guttural pouch. Its posterior fibres blend with those of the origin of the digastricus. Action. — It draws back and depresses the os hyoides. palpebral group. 173 Palpebral Group, The palpebral, or muscles of the eyelids are four in number, named as follows : — Orbicularis palpebrarum. Lacbrymalis. Levator palpebrse superioris externus. Levator palpebrse superioris internus. ORBICULARIS PALPEBRARUM. {Musculus Ciliaris.) (PL. II. 5. Fig. 70. //.) A large, thin, oval sphincter, common to the upper and lower eyelids, and situated around them. Attachments. — It is covered by the skin, to which it inti- mately adheres. The superior portion is the larger, and consists of numerous fleshy fasciculi, with a small flat tendon which is attached to the lachrymal tubercle, near the nasal angle of the eye. Action.- — It closes the eyelids. LACHRYMALIS. {Lachrymo-LabiaUs.) A very thin muscle placed below and before the orbit, con- tinuous with the levator labii superioris in front, the panniculus behindj and the orbicularis palpebrarum above. It becomes blended with the buccinator. LEVATOR PALPEBRiE SUPERIORIS EXTERNUS. (Fronto-superciliaris.) (Fig. 70. e.) Situated immediately above the orbit, it is subcutaneous, short, thin, and narrow. Attachments. — It arises from the external surface of the frontal bone, near the supra- orbital foramen. The fibres pass downwards and outwards, blending with the orbicularis at the superior part of the lid, towards the inner angle of the eye. 174 MYOLOGY. Relation. — Externally with the skin; internally with th& bone. Action. — It corrugates the skin of the upper eyelid, but is scarcely a levator, LEVATOR PALPEBR^ SUPERIORIS INTERNUS. (Orbito-palpebralis. ) Situated within the orbital fossa, in relation with the superior straight tnuscle of the eyeball, this muscle is narrow, thin, and band-like. Origin. — From the superior border of the optic foramen, on a level with the lachrymal gland, passing under which it becomes aponeurotic, running between the conjunctiva and the fibrous portion of the upper lid. Insertion. — To the inner surface of the lid, and the tarsal cartilage. Action. — It raises the upper eyelid. Auricular Group. The external muscles of the ear consist of an extrinsic and an intrinsic group. The extrinsic muscles, eight in number, are as follows : — AttoUens maximus. Ketrahens externus. AttoUens anticus. Retrahens medius. AttoUens posticus. Retrahens internus. Abducens. Mastoido-auricularis. ATTOLLENS MAXIMUS. (Temporo-auricularis Externus. ) (PL. IL 2'.. Situated immediately under the skin, above the temporal muscle, and in front of the inner side of the ear, it is broad, thin, and fleshy. Origin. — From the whole of the parietal crest, joining its fellow in the mesian line posteriorly. Insertion. — To the scutiform cartilage, sending a small band to the internal border of the base of the conchal cartilage. AURICULAR GROUP. 175 Relation. — Externally with the skin; internally with the temporalis and attoUens posticus ; posteriorly with the retrahens externus. Action. — It adducts and elevates the ear, and also turns its opening forwards. ATTOLLENS ANTICUS. {^Zygomatico-auricularis. ) (PL. II. 2".) Subcutaneous, and in front of the ear, this muscle is small and thin, consisting generally of two fleshy bundles, joined by condensed cellular tissue. ^^y^^W^^. Fig. 72. Muscles of the external ear — posterior view, a. Inferior, and 6, superior layer of the scuto-auricularis internus ; c, AttoUens posticus ; d, Retrahens externus; e, Ketrahens medius ; /, Retrahens internus; g, Mastoido-aiiricularis. Origin. — From the superior part of the temporal zygomatic process by a flat tendon, which blends in front with the orbicu- laris palpebrarum. Insertion. — By two sets of fibres — one to the anterior part of the scutiform, the other to base of the conchal cartilage, blending with the scuto-auricularis externus and the abducens. Relation. — Externally with the skin ; internally with the temporal muscle ; posteriorly with the parotid gland. Action. — It draws the ear forwards. 176 MYOLOGY. ATTOLLENS POSTICUS. (Temporo-auricularis Internua.) (Fig. 72. c.) This is a triangular muscle of a bright-red colour, situated under the attollens maxiraus. Origin. — From the parietal crest, and by cellular tissue from the temporalis. Insertion. — The tendon is directed obliquely round the inter- nal face of the concha, terminating in the conchal cartilage, below the insertion of the retrahens externus. Relation. — Externally with the maximus ; internally with the temporalis. Action. — It elevates and adducts the ear. RETEAHENS EXTERNUS. (Cervico-auricularis Externus.) (Fig. 72. d.) Situated on the poll, at the side of the ear, it is thin and flat, joining the attollens maximus. Origin. — From the cordiform portion of the ligamentum nuchse. Insertion. — To the middle of the posterior surface of the conchal cartilage. Relation. — Externally with the skin ; internally with the retrahens internus and medius. Action. — It draws the ear backwards and downwards. RETRAHENS MEDIUS. (Cervico-auricularis Medius.) (Fig. 72. e.) Broad and thin ; situated below the preceding. Origin. — The same as the externus. InseHion. — To the external part of the base of the concha under the abducens, its tendon passing over the superior portion of the parotid gland. Relation. — Externally with the preceding muscle ; internally with the internus aud the parotid gland. Action. — It rotates the ear, turning the opening backwards. AURICULAR GROUP. 177 RETRAHENS INTERNUS, {Cervico-auricularis' Inter nus. ) (FiQ. 72./.) Thin, fleshy, and situated below the preceding muscle. Origin. — The same as the two last named. Insertion. — To the dilated lower part of the conchal car- tilage. Relation. — Externally with the medius and the parotid gland. Action. — It assists the medius. MASTOIDO-AURICULARIS. (Fig. 72. g.) Situated deeply, at the base and inner side of the concha, -this muscle is very small, flat, and slender. Origin. — From the external auditory meatus Insertion. — To the base of the concha. Action. — It draws the concha downwards, and thus shortens Ae external ear. ABDUCENS. {Deprimens Aurem — Parotido-auricularis.) {Pl. II. 1. Fig, 70. a.) Situated below the root of the ear, and on the outer side of the parotid gland, it is flat and thin below, narrower and thicker above. Origin. — From tbe external surface of the parotid gland. Insertion. — To the external part of the base of the concha. Relation. — Externally with a thin aponeurotic portion of the panniculus ; internally with the parotid gland. Action. — It draws the ear downwards and outwards. INTRINSIC MUSCLES. The intrinsic muscles of the external ear are the scuto-auri- cularis. externus and internus. 178 MYOLOGY. SCUTO-AURICULA.EIS EXTEENUS. (Fig. 70. b. c. d.) Origin. — From the external surface of the scutiform car- tilage. Insertion. — To the inner side of the conchal cartilage. It is composed of three bundles, covered by the attollens maximus, and it assists that muscle to turn the openiog of the ear forwards. SCUTO-AURICULARIS INTEHNUS. (Fig. 72. a. b.) It consists of two pale bundles which cross each other. Origin. — The under surface of the scutiform cartilage, the •fibres being directed backwards. Insertion. — The posterior portion of the base of the concha. Action. — It turns the opening of the ear outwards and back- ivwards, thus antagonising the externus. Muscles of the Trunk. This large division includes the rest of the muscles, excepting those which more especially belong to the limbs. We shall divide the trunk into the following regions, thus indicating the groups ,into which the muscles most naturally fall : — Diaphragmatic. Dorso-lumbar. Sublumbar. Coccygeal. Cervical Kegion. Cervical. Pectoral. Costal Abdominal. The muscles of the neck may be said to consist of an inferior and two lateral groups, the latter lying on each side of the central division formed by the vertebrae and the ligamentum nuchse, and the former being situated underneath the vertebrae. Inferior Cervical Group. The following muscles, eight in number, may be placed in this group : INFERIOR CERVICAL GROUA 179 Sterno-maxillaris, Stemo-thyro-hyoideus. Subscapulo-h yoideus. Rectus capitus anticus major. Rectus capitis anticus minor. Rectus capitus lateralis. Scalenus. Longus colli. STERNO-MAXILLARIS. (Pl. IL 20.) Placed along the lower border of the levator humeri, this muscle is long, narrow, and flat, its fibres extending forwards and upwards ; it is fleshy, terminating in a flat tendon. Origin. — From the anterior portion of the cariniform cartilage: it is united to its fellow along its inferior third. Insertion. — To the angle of the lower jaw. Relation. — Externally with the panniculus and the parotid gland ; internally with the sterno-thyro-hyoideus and subscapulo- hyoideus, the trachea and carotid artery ; the jugular vein runs along its superior border. Action. — Acting with its fellow, it flexes the head downwards, or singly, it turns the head to one side. STERNO-THYRO-HYOIDEUS. (Sterno-thyroideus and Sterno-hyoideus.) (Pl. IIL 3.) This is a slender muscle situated in front of the trachea ; it is narrow, ribbon-shaped, and divided into two parts. Fleshy at its origin, it divides half way up the neck into two portions, each having a tendon of insertion. About their middle the sterno- thyro-hyodei have tendinous intersections, which render tl^em more or less digastric. Origin. — From the superior part of the cariniform cartilage, intimately blended with its fellow. Insertion. — By one tendon, to the postero-inferior part of the thyroid cartilage, and by the other to the spur process of the os hyoides. Relation. — Inferiprly with the sterno-maxillaris ; superiorly with the trachea. Action. — It depresses the hyoid bone, and with it the larynx and base of the tongue. 180 * MYOLOGY. SUBSCAPULO-HYOIDEUS. (PL. n. 23.) More laterally situated than the last, this muscle is broad, thin, and elongated, its fibres extending forwards and upwards. Aponeurotic at its origin, it is followed by a long, flat, fleshy belly, ending', in a flat tendon, which joins that of the stemo- hyoideus. OHgin. — From the fascia covering the subscapularis muscle. Insertion. — To the inferior border of the spur process of the OS hyoides. Relation. — Externally with the subscapularis, pectoralis parvus, and sterno-m axillaris, blending also with the levator humeri; internally with the muscles on the inner aspect of the shoulder, the scalenus and rectus capitis anticus major, the trachea and the carotid sheath. Action. — It depresses the hyoid apparatus. RECTUS CAPITIS ANTICUS MAJOR. ( Trachelo-suhoccipitalis. ) (PL. III. 2.) This is the long flexor of the head, and is situated along the anterior half of the region. It is long, and has a flattened, fleshy belly, converging from two or three slips of origin, and teiminat- ing anteriorly in a conical tendon. Origin. — Posteriorly, from the transverse processes of the third, fourth, and fifth cervical vertebrsB. Insertion. — To the basilar process of the occipital and body of the sphenoid bone. Relation. — Externally with the levator humeri, and subscapulo- hyoideus ; internally witb its fellow and the longus colli ; anteriorly with the gutteral pouch and carotid artery, and superiorly with the occipito-atloid joint, and rectus capitis, anticus minor. Action. With its fellow it flexes the head downwards ; when acting singly, it flexes it laterally. INFERIOR CERVICAL GROUP. 181 RECTUS CAPITIS ANTICUS MINOR. (Atloido-suboccipitalis. ) (Fia. 75. c.) This, the short flexor of the head, is situated on the inner and upper side of the preceding muscle, and is short, slender, and almost entirely fleshy. Origin . — Posteriorly, from the lower part of the body of the atlas. Insertion. — To the basilar process of the occipital, and body of the sphenoid bone, by the preceding muscle. Relation. — Infero-externally with the rectus major ; supe- riorly with the capsular ligament of the occipito-atloid articu- lation. A.ction. — It assists in flexing the head. RECTUS CAPITIS LATERALIS. {A tloido-styloideus.) (Fig. 75. 6.) This muscle, still smaller than the last and like it in structure, is placed rather more externally. Origin. — From the inferior part of the ring of the atlas, on the outer side of the rectus minor. Insertion. — To the styloid process of the occipital bone. Relation. — Inferiorly with the rectus major ; superiorly with the capsular ligament of the occipito-atloid articulation ; exter- nally with the parotid gland. Action. — It assists the preceding muscles. SCALENUS. ( Costo-cervicalis. ) (PL. IIL 6.) Situated at the postero-inferior part of the region, at the side of the anterior aperture of the thoracic cavity, the scalenus is triangular in shape, and divided into a superior or posterior, and an inferior or anterior portion ; the fibres run forwards and upwards, and form several fleshy masses, with strong tendinous 182 MYOLOGY. intersections. The anterior portion is the larger, flat from side to side, and thin in front. Origin of the Anterior Portion. — From the transverse pro- cesses of the last four cervical vertebra by short fleshy fasciculi. Insertion. — The anterior and outer border of the first rib. Origin of the Posterior Portion. — From the transverse pro- cesses of the last three or four cervical vertebrae. Insertion. — To the superior part of the first rib. Relation. — Superiorly with the intertransversalis colli; inferiorly with the sterno-maxillaris ; externally with the levator humeri, pectoralis parvus, and subscapulo-hyoideus ; internally with the trachea and carotid artery, and on the left side with the oesopha- gus. Across its inferior border runs the jugular vein, and between its anterior and posterior portions pass the nerves of the brachial plexus. Action. — When the first rib is fixed, together these muscles extend the neck ; acting singly, each turns it to one side. When the neck is fixed, by drawing the first rib forward and supporting it, it acts as an inspiratory muscle. LONGUS COLLI. (Subdorso-atloidevs.) (Fig. 75. a.) In the horse this is a single muscle, situated under the centra of the cervical and anterior dorsal vertebrae. The dorsal portion is fleshy, the cervical being made up of smaller fasciculi, con- voluted and intersected by tendinous fibres. The fasciculi run inwards and forwards. Origin. — From the inferior surface of the centra of ther first six dorsal, and the inferior spines and transverse processes of the six posterior cervical vertebrae. Insertion. — By a strong tendon to the inferior spine or tubercle of the atlas ; it is also strongly attached to the second cervical segment. Relation. — Externally and anteriorly with the rectus capitis anticus major ; externally and posteriorly with the scalenus ; inferiorly with the trachea, oesophagus, blood-vessels, and nerves ; superiorly with the vertebroB. The dorsal portion is related with v the pleura and sympathetic nerves. LATEBAL CEEVICAL GROUT, 183 Action. — It flexes the neck downwards, and moves one vertebra on another. Lateral Ceevical Group. This is a numerous group, but one difficult of satisfactory suo- division. The following Table enumerates the muscles in the order in which they may be conveniently demonstrated : — Levator humeri. Trapezius cervicalis. Rhomboideus longus. Serratus magnus (a portion). Splenius Trachelo-mastoideus. Complexus major. Complexus minor. Rectus capitis posticus major. Rectus capitis posticus minor. Obliquus capitis anticus. ObUquus capitis posticus. Spinalis colli. Litertransversalis colli. LEVATOR HUMERI. (Mastoido-humeralis.) (Pl. IL 12.) Occupying the infero-lateral part of the neck, this muscle is large, flat, and elongated, extending downwards from, the back of the head to the arm. Its fleshy portion is divisible into deep and superficial parts, the first being placed anteriorly. Attachments. — Anteriorly, by one tendon to the crest of the occiput and the mastoid process of the temporal bone ; by the other to the wing of the atlas, this tendon being also common to the splenius and trachelo-ma,stoideus ; to the transverse processes of the second, third, and fourth cervical vertebrse, and the fascia of the neck. Covering the shoulder joint, it is attached to a line extending downwards from the deltoid ridge ; and to the fascia of the muscles of the shoulder and arm, joining the scapular fascia by an aponeurotic expansion continuous also with the fascia of the cervical trapezius. Relation. — Externally with the panniculus ; inferiorly with the carotid artery, jugular vein, and stemo-maxillaris ; internally with the splenius, trachelo-mastoideus, rectus capitis anticus major, scalenus, serratus magnus, and other muscles ; anteriorly with the parotid gland. It is connected with the ligamentum nuchas by the aponeurosis of the panniculus, and infero-laterally becomes 184 MTOLOGY. blended with that muscle ; hence it may be said to have an. indirect sternal attachment. Action. — When the head is fixed, it advances the entire limbj if the limbs are fixed, it aids in turning the head and neck to- one side, or with its fellow in depressing them. TRAPEZIUS CERVICALIS. (Cervico-acromialis.) (PL. n. 13.) Situated supero-posteriorly, this, the cervical portion of the- trapezius muscle, is thin, flat, and triangular, its fibres converging downwards and backwards. It is aponeurotic above, and poste- riorly, where it joins the dorsal portion. Origin. — ^From the funicular portion of the ligamentum nuchas. iTisertion. — With the dorsal trapezius to the spine of the scapula, at its tubercle, and to the scapular fescia. Relation. — Externally with fascia from the levator humeri and panniculus ; internally with the splenius, serratus magnus, rhom- boideus longus, pectoralis parvus, and antea spinatus. Action. — It elevates, and draws the shoulder forwards. RHOMBOIDEUS LONGUS. (Cervico-subscapularis. ) (PL. III. 9.) It is placed on the supero-lateral part of the neck, just below the cordiform portion of the ligamentum nuchaB. It appears as a tapering triangle, widest posteriorly, and very fleshy in its structure. Origin. — From the funicular portion of the ligamentum nuchae, as high as the second cervical vertebra Insertion. — To the inner surface of the anterior angle of the scapula, and to its cartilage of prolongation, just above the serratus magDus. Relation. — Externally with the cervical trapezius ; inferiorly with the splenius ; posteriorly with the rhomboideus brevis, with which it blends ; internally with the ligamentum nuchse. Action. — To elevate and draw the scapula forwards. LATERAL CERVICAL GROUP. 185 SERRATUS MAGNUS. (PL. HL 10.) The cervical portion of the serratus magnus will be described -with the costal portion. (See costal region.) SPLENIUS. {Cervico-mastoideus. ) (PL. III. 7.) This is a large muscle included between the funicular part of the Ugamentum nuchse, and the vertebrae below. It is broad. Fig. 73. Lateral cervical muscles-deep layer, a, Complexus major; 6, Trachelo-mastoideus ; eccc, Intertransversalis eolH- liat, and triangular ; aponeurotic only at its periphery, its belly is made up of large fleshy bundles, which are directed obliquely forwards and upwards to the head and first cervical vertebra. Attachments.—To the funicular portion of the ligamentum nuchse, the transverse processes of the third, fourth, and fifth cervical, and the spines of the first four or five dorsal vertebrae ; to the crest and mastoid ridge, in union with the tendon of the trachelo-mastoideus, and to the wing of the atlas, aloug with the common tendon of the trachelo-mastoideus and the levator humeri. 186 MYOLOGY. Relation. — Externally with the levator humeri, cervical trape- zius, serratus magnus, and rhomboideus muscles; internally with the complexus major, trachelo-mastoideus, and obliquus capitis muscles. Action. — With its fellow it elevates the head; alone it draws the head to one side. TRACHELO-MASTOIDEUS.* (Dorso-mastoideus. ) (Fig. 73. ft.) Situated under and along tbe inferior border of the splenius, it is elongated and flesby, its fibres passing forwards and upwards ; the belly is divided into two portions, which run parallel, each terminating by a tendon anteriorly. Origin. — From the transverse processes of the first two dorsal and the oblique processes of the last five cervical vertebraB. Insertion. — By two tendons ; one to the wing of the atlas, common also to the splenius and levator humeri ; the other, continuous with that of the splenius, to the mastoid ridge. Relation. — Externally with the splenius ; internally with the spinalis colli ; posteriorly with the longissimus and spinalis dorsi. Action. — With its fellow to erect the head ; acting alone, it draws it to one side. COMPLEXUS MAJOR. (Dorso-occipitalis. ) (Fig. 73. a.) Situated on the inside of the splenius, this muscle resembles an elongated triangle, with the base backwards ; it is fleshy, with tendinous intersections. The posterior part is aponeurotic at its origin, the anterior terminating in a single tendon. Origin. — From the transverse and spinous processes of the first five dorsal, and the oblique processes of all the cervical vertebrae. Insertion. — To the side of the occipital tuberosity. Relation. — Externally with the splenius and trachelo-* mastoideus ; internally with the complexus minor, ligamentum nuchse, and oblique muscles ; posteriorly with the longissimus * This is the complexus minor of M. Chauveau. LATERAL CERVICAL GROUP. 187 and spinalis dorsi. The superior cervical artery passes through its divisions posteriorly. Action. — It extends the head. COMPLEXUS MINOR. (Axoido-occipitalis Longus.) (Fig. 74. c.) Situated on the poll, it is fusiform, slender, and fleshy, being tendinous at its insertion. Origin. — From the neural spine of the dentata. Insertion. — With the tendon of the complexus major. Relation. — Externally with the complexus major; inferiorly with the rectus capitis posticus major; internally with the liga- mentum nuchse. Action. — To assist the complexus major. RECTUS CAPITIS POSTICUS MAJOR. (Axoido-occipitalis Brevis.) (Fig. 74. d.) Situated below the complexus minor, it is long, slender, and fusiform. Origin. — From the neural spine of the dentata. Insertion. — To a roughened depression on the occiput below its tubercle. Relation. — Externally with the complexus major ; inferiorly with the rectus capitis posticus minor. Action. — To extend the head. RECTUS CAPITIS POSTICUS MINOR. (Atloido-occipitalis Brevis.) (Fig. 74. e.) Situated below the preceding, this muscle is small, flat, and somewhat triangular. Origin. — From the supero-anterior part of the atlas. Insertion. — Below that of the preceding muscle. Relation. — Superiorly with the major ; inferiorly with the capsular ligament ; externally with the obliquus capitis anticus ; internally with the ligamentum nuchas. Action. — It assists the preceding muscle. 188 MYOLOGY. OBLIQUUS CAPITIS ANTICUS. (Atloido-mastoideus.) (Fig. 74. b.) Situated on the side of the poll, it is flat, nearly square, and' ■fleshy, with tendinous intersections. Origin. — From the supero-anterior portion c^ the roughened edge of the wing of the atlas. Insertion. — To the mastoid crest and styloid process of the occiput. Occipito-atlo-axoid muscles— lateral view, a, Obliqnus capitis posticus ; b, Obliqnus capitis anticus; c, Complexus minor ; d, Rectus capitis posticus major; e, Eectus capitis posticus minor. Relation. — Externally with the tendon of the splenius ; internally with the caosular ligament and rectus capitis posticus muscles. Action. — Together, to extend the head slightly; singly, to bend it laterally on the atlas. OBLIQUUS CAPITIS POSTICUS. {Axoido-atloideus.) (Fig. 74. a.) Situated between and upon the atlas and axis, it is broad, flat, thick, and fleshy. LATERAL CERVICAL GROUP. 189 Origin. — From the lateral surface and superior spine of the dentata, and the capsular ligament. Insertion. — To the upper surface of the wing and body of the atlas. Relation. — Externally with the splenius, trachelo-mastoideus, and complexus major ; internally with the atlas, axis, and the atlo- axoid capsular ligament ; superiorly with the rectus posticus, and inferiorly with the rectus anticus major muscles. Action. — It is the rotator muscle of the head. SPINALIS COLLL {Dorso-spinalis. ) Deep-seated on the side of the neck, it consists of six short fleshy bundles, intersected by tendons, whose fibres extend obliquely upwards and inwards. Origin. — Posteriorly, from the oblique processes of the first dorsal and the last five cervical vertebrae. Insertion. — To the neural spines of all the cervical vertebrae but the first. Relation. — ^Externally with the complexus major and trachelo- mastoideus ; internally with the ligamentum nuchae and the vertebrae. Action. — To extend and curve the neck. Intertransversalis Colli. (Intercervicalis. ) (Fig. 73. c c c c.) Placed along the lateral part of the cervical vertebrae, it ■consists of six distinct bundles with strong tendinous intersections, the fibres passing obliquely outwards and upwards. Origin. — The oblique process of one vertebra. Insertion. — The transverse process of the vertebra in front, filling up the interspaces of all, excepting those of the first and second. Relation. — With several deep-seated muscles of the neck, the vertebrae, the vertebral artery, and vein. Action. — To assist in flexing the neck laterally. 190 MYOLOGY, Costal Region. The muscles of this region are those which cover the lateral aspect of the thoracic cavity ; some of them are attached to the anterior limb, three of which we describe the first, as it is necessary in dissection to cut through them, -and remove or deflect the limb in order to expose fully the deeper-seated muscles. The following are the muscles of the region : — Trapezius dorsalis. Rhomboidfius brevis. Lafcissimus dorsi. Serratus magnus. Superficialis costaruni. Transversalis costarum. Levatores costarum. Intercostal es. TRAPEZIUS DORSALIS. {Dorso-acromialis.) (Pl. IL 14.) Situated on the side of the withers, this muscle is flat and triangular, being almost the reversed counterpart of the cervical trapezius. The two form the trapezius muscle. It is aponeu- rotic at its superior border, while its belly is fleshy, terminating; la a flat tendpn. Origin. — Superiorly, from the supraspinous ligament, and from the third dorsal spine back to the tenth or eleventh. The fibres converge downwards and forwards, over the superior costa. of the scapula, and join the cervical portion. Insertion. — The tubercle on the spine of the scapula. Relation. — Externally with the skin and panniculus; internally with the rhomboideus brevis, postea-spinatus, and latissimus. dorsi. Action. — To draw upwards and retract the scapula. KHOMBOIDEUS BREVIS. (Dorso-subscapularis.) (Pl, in, 12,) Deep-seated, on the side of the withers above the scapula, it is flat and square ; the fibres extend downwards, and are entirely COSTAL EEGION. 191 Origin. — From the neural spines of the first four or five dorsal vertebrae, and from their supraspinous ligament. Insertion. — To the inner surface of the superior costa of the scapula, and to its cartilage of prolongation. Relation. — Externally with the cartilage of the scapula, and the dorsal trapezius, and separated from the anterior portion of the superficialis costarum by a thin layer of elastic tissue ; anteriorly with the rhomboideus longus ; posteriorly with the latissimus dorsi; internally with the splenius. Action. — To draw the scapula upwards. LATISSIMUS DORSI ( Dorso-humeralis. ) (PL. IL 15.) This muscle is situated on the supero-lateral part of the chest and the loins ; it is very large, flat, thick, and triangular, its fibres extending obliquely downwards and forwards ; it is aponeu- rotic above, fleshy below, with a tendinous and aponeurotic insertion. Origin. — By a broad aponeurosis, from the supraspinous liga- ment and spinous processes of the vertebrae, commencing about the highest point of the withers, and stretching as far as the last lumbar. The fleshy portion becomes thick just behind the scapula, then it contracts, terminating in a flat tendon, which passes under the latter. It fits in a notch at the dorsal scapular angle, formed by the projection of the cartilage of prolongation, which it overlaps. Insertion. — The internal tuberosity of the humerus, along with the teres internus, and between the two insertions of the coraco-humeralis. Before passing under the scapula, it gives oflf a strong aponeurosis, which passes over the supero-posterior part of the scapula, and becomes continuous with its fascia. Relation. — Externally with the panniculus carnosus, skin, triceps extensor brachii, and dorsal trajoezius; superiorly with the rhomboideus brevis and dorsal angle of the scapula ; inter- nally with the ribs, serratus magnus, superficialis costarum, and gluteus maximus. Action. — To elevate the humerus, and thus flex the shoulder- joint; it is likewise an expiratory muscle, when the limb is fixed. 192 MYOLOGY SERRATtJS MAGNUS. {Costo-suhacapularis. ) (PL. III. 10. 15.) Situated between the shoulder and chest, and on the side of the neck, this is a large fan-shaped muscle ; it may be divided into a cervical and a costal portion, and consists of several bundles with many tendinous intersections, converging upwards to the common point of insertion. Origin. — Anteriorly, from the transverse processes of the five posterior cervical vertebrae ; postero-inferiorly, from the external surfaces of the eight true ribs, from about their middles to their cartilages. Insertion. — Superiorly to the venter surface of the scapula, between the origin of the subscapularis and the insertion of the rhomboidei. Relation. — Anteriorly with the splenius ; superiorly with the rhomboidei ; supero-posteriorly with the longissimus dorsi ; poste- riorly with the great oblique muscle of the abdomen, with which it interdigitates ; inferiorly with the pectorals ; internally with the ribs, longissimus dorsi, splenius, cervical vertebrae, and intercostals ; externally with the subscapular and triceps extensor muscles. Action. — It depresses the scapula ; when the limbs are fixed, it elevates the neck, and is also a subservient muscle of inspiration ; but it chiefly serves with its fellow as a muscular sling, in which the body is suspended between the anterior limbs. SUPERFICIALIS COSTARUM. {Dorso-costalis.) (Pl. II. 49.) Placed on the supero-lateral part of the back, this muscle is broad, thin, and digitated, and consists of an anterior and a posterior portion. Origin. — Ajiteriorly, from the supraspinous ligament, and dorsal spines from the second to the thirteenth inclusive; posteriorly from the spines of the last eight dorsal and anterior lumbar vertebrae. Insertion. — The anterior part to the nine ribs behind the fourth, just below their angles, and to their anterior borders ; the posterior part to the posterior borders of the last nine ribs. EXPLANATION OF PLATE IIL Muscles of the Horse. Deep Layer. 1, Temporalis. 22. Humeralis obliquus. 1 . Stylo-maxillaris, 22'. Caput parvum (of triceps extensor 2. Rectus capitis anticus major. brachii). 3. Stemo-thyro-liyoideiis. 23. Extensor sufFraginis. 4. Sterno-maxillaris. 24.Extensormetacarpimagnusdivided. 5. The Trachea. 25. Extensor metacarpi obliquus 6. Scalenus. 25'. Its tendon. 7. Spfenius. 26, 28. Flexor pedis perforaus and per* 8. Funicular part of ligamentum foratus. nuchas. 29. Obliquus abdominis internus. 9. Rhomboideus longus. 30. Gluteus maximus.. 10. Cervical-) serratus maguus. 15. Costal / 31. Erector coccygi.s. 32. Curvator coccygis. 11. Cartilage of prolongation. 33. Depressor coccygis. 12. Rhomboideus brevis. 34. Rectus femoris. 13. Transversalis costarum. 35. Vastus externus. 14. Longissimus dorsi. 36. Part covered by triceps abductor. 15. Serratus Magnus. 37. Biceps rotator tibialis. 16. External intercostals. 38. Gastrocnemius externus. 17. Internal intercostals. 39. Plantaris. 18. Rectus abdominis. 40. Flexor pedis perforans. 19 19. Pectoralis magnus. 41. Peroneus. 20. Postea-spinatus minor. 42. Flexor metatarsi. 21. Flexor brachii. 43. Extensor pedis (cut across). COSTAL REGION. 19? Relation. — Internally with the ribs, transversalis costarum, and longissimus dorsi ; externally with the rhomboideus, serratus magnus, and latissimus dorsL Action. — Respiratory; the anterior portion drawing the ribs outwards and forwards, acts as an inspiratory, the posterior, by drawing them backwards and upwards, as an expiratory muscle. TRANSVERSALIS COSTARUM. ( Trachelo-costalis. ) (Pl. IIL 13.) Situated on the supero-lateral part of the thorax, it is long, thin, and semipenniform, the fibres passing downwards, outwards, and forwards, its numerous muscular bundles each terminating in a flat tendon. Origin. — From the transverse processes of the first lumbar vertebrae, and the ribs near their tubercles. Insertion. — To the external surface of all the ribs, a tendon to each, and one to the last cervical vetebra. Relation. — Externally with the preceding muscle ; internally with the ribs; superiorly with the longissimus dorsi. Action. — It compresses the ribs, assisting in expiration. LEVATORES COSTARUM. (Transverso-costalis.) Situated deeply on the back, these muscles are small, flat, and triangular, extending obliquely downwards and backwards. They are fleshy and tendinous. Origin. — Superiorly, from the transverse processes of the dorsal vertebrae, just above the tubercles of the ribs. Insertion. — Inferiorly to the external faces of the ribs, just above their angles. Relation. — Externally with the longissimus dorsi ; internally with the external intercostals, with which posteriorly they are much blended. Action. — To raise and draw the ribs forwards, thus acting as inspiratory muscles. o 194 INTERCOSTALES. {Externi and Interni). (PL. III. 16. 17). These fill up the spaces between the ribs, are external and internal, and usually seventeen in number, consisting of flat bands, included in, and intersected by, many broad aponeurotic slips. The external ones are thickest above, the internal below, the former terminating at the costal cartilages, between which the latter extend. Origin. — From the posterior border of each rib. Insertion. — The anterior border of each succeeding rib, the 'fibres of the external ones extending downwards and backwards, those of the internal ones downwards and forwards. The external terminate at the costal cartilages, while the internal do not extend above the angles. Relation — Externally with the serratus magnus, superiicialis and transversalis costaruni, and latissimus dorsi ; internally with the pleura. Action. — They are inspiratory muscles, drawing the ribs for- ward, the first rib being rendered a fixed point by the contraction of the scalenus. They thus aid the diaphragm in its action. Pectoral Region. In this region we describe two groups of muscles, the 'pectoral and the sternal, the latter being deep-seated. Pectoral Group. This group consists of four pairs of musclep. which are largely developed in the horse, and all of which arise from the external surface of the sternum and its appendages, and become attached to the pectoral limb, upon which they, as a group, assist in sus- pending the body, also in moving the limb, and in respiration. They are differently described by different authorities ; Percival and Leyh describe three pairs, Chauveau two, but as the latter divides each of them into two parts, his consideration ultimately agrees with the one adopted here. We describe four pairs of pectoral muscles : — Pectoralis transversus. I Pectoralis anticup. Pectoralis magnus. | Pectoralis parvus. PECTORAL GROUP. 195 PECTORALIS TRANSVERSUS. (Sterno-aponeuroticus. ) (Fig. 75. d.) Situated on the latero-inferior part of the thorax, this muscle is quadrilateral, the fibres extending outwards and- downwards. Fto. 75. Peetoral muscles, and inferior deep muscles of the neck, a, Longus colli ; h, Rectus capitis lateralis ; c, Rectus capitis anticus minor ; d, Pectoralis transversus ; e, Pectoralis antijcns ; //, Pectoralis magnus ; g, Pectoralis parTus. On the left side the pectoralis transversus and anticus have been removed. Near its origin it is fleshy, mixed with tendon, but. afterwards becomes aponeurotic. Origin. — By fleshy fibres usually from the first four bones of the sternum, meeting its fellow at a white central line. Insertion. — To the olecranon, by fascia covering the inner side of the arm, and to the anterior part of the humerus. Relation. — Externally with the skin ; anteriorly with • the pectoralis anticus ; superiorly with the pectoralis magnus. Action. — To adduct the arm, and especially to tense the "brachial fascia. 196 MYOLOGY. PECTORALIS MAGNUS. (Sterno-trochineus. ) (Pl. III. 19, 19. Fig. 75.//.) This muscle is situated on the infero-lateral part of the thorax, and is large, irregularly four-sided, flat, and thick, the fibres extending forwards and outwards. Slightly aponeurotic ante- riorly, elsewhere it is fleshy. Origin. — From the inferior border of the last three or four bones of the sternum, the ensiform cartilage, and its fellow of the opposite side ; externally from the cartilages of the false ribs, fascia of the external oblique muscle of the abdomen, and the abdominal tunic. Insertion. — To the fascia on the inside of the arm, and to the inner trochanter of the humerus, under the tendon of the coraco- humeralis, and by fascia over the bicipital groove, to the external trochanter. Relations. — Externally with the panniculus, skin, and pectoralis transversus ; internally with the fascia of the external oblique, and the ribs ; anteriorly with the pectoralis parvus. Action. — To draw the shoulder back and adduct the arm ; in difficult respiration it acts as an inspiratory muscle. PECTORALIS ANTICUS. {Sterno-humeraiis. ) (Fig. 75. e.) Situated on the anterior part of the breast, it forms the fleshy prominence seen in front. Short, thick, and fusiform, its fibres extend outwards ; it is tendinous at its attachments, with a fleshy belly. Origin. — From the cariniform cartilage and first bone of the €tenium. It is directed somewhat backwards, outwards, and ■downwards. Insertion. — To a ridge on the anterior part of the shaft of the humerus by fleshy fibres, and an aponeurotic tendon common also to the levator humeri, and pectoralis transversus. Relations. — Externally with the skin ; anteriorly with the levator humeri and panniculus ; posteriorly with the pectoralis magnus and transversus ; internally with the parvus. Action. — Its chief action is to adduct the arm. STERNAL GROUP, 197 PECTORALIS PARVUS. (jSterno-prescapularis. ) (Fig. 75. g.) In front of the magnus, on the antero-iuferior part of the Ihorax, elongated and prismatic in form, its fibres extend out- wards, forwards, and upwards ; it is tendinous at its origin, fleshy elsewhere. Origin. — From the three or four anterior sternal segments, cartilages, ribs, and carinifori^ cartilage. Insertion. — To the fascia in front of the shoulder-joint, and the anterior costa of the scapula, nearly as high up as the origin of the antea-spinatus. Relation. — Externally with the magnus and transversus ; inferiorly with the transversus and anticus ; internally with the first costal cartilages, intercostales, and transversalis costarum ; anteriorly with the levator humeri. Action. — To draw the shoulder-joint backwards and down- wards, assist the magnus, and tense the scapular fascia. Sternal Group. The muscles of this unimportant group are two in number — Lateralis stern i. Triangularis sterni. LATERALIS STERNL {Costo-sternalis. ) Placed along the inferior border of the serratus magnus, its ^fibres extend downwards and backwards. It is flat, thin, and aponeurotic at its extremities. Origin. — From the outer surface of the first rib, passing over the next two or three ribs, and becoming attached to the ster- num at about the fourth segment. Relation. — Externally with the pectorals ; superiorly with the serratus magnus ; posteriorly with the rectus abdominis ; inter- nally with the ribs and intercostals. Action. — An auxiliary muscle of expiration. 198 MYOLOGY. TRIANGULARIS STERNI. {Sterno-costalis.) Situated in the thorax and upon the steraum, it is triangular^ tendinous, and dentated on its outer border. Origin. — From the superior sternal ligament and segments. Insertion. — To the cartilages, and inner surfaces of the distal ends of the true ribs, e.Kcepting the first. Action. — To assist in expiration. DORSO-LUMBAR REGION. The muscles of this region, a smgle group, are closely related with the superior aspect of the vertebral column, and we describe them as consisting of four — Longissimus dorsi. I Semispinalis dorsi et lumborum. Spinalis dorsi. | Intertransversales lumborum. LONGISSIMUS DORSI. (Ilio-spinalis.) (Pl. in. 14.) Situated on the superior part of the back and loins, this, the longest and most powerful muscle in the body, occupies the space between the costal angles and the dorso-lumbar spines ; broad and fleshy at its origin in the loins, it becomes deeper and narrower as it proceeds forwards. Towards the withers it diverges, presenting three distinct portions, two of which proceed in an oblique direction to the neck, and terminate by several tendons (the deeper portion is described as the spinalis dorsi) ; the third portion is adherent to the sides of the anterior dorsal spines. The belly of this muscle is intersected by several tendons, and is invested posteriorly by a very strong, tendinous aponeurosis. Attachments. — The crest, inner surface, and supero-anterior spine of the ilium ; the spinous and transverse processes of the first two bones of the sacrum ; the spinous, transverse, and oblique processes of all the lumbar vertebrae ; the spinous and transverse processes of all the dorsal vertebrse; the external surface of the last fifteen or sixteen ribs just above the trans- versalis costarum, and the spinous and transverse processes of the last three or four cervical vertebrse. DOESO-LUMBAR REGIOM. 199 Relation. — Externally with the superficialis cdstarum, and gluteus maximus which overlaps it in the lumbar region; in- feriorly with the transversalis costarum ; internally with the ribs, vertebrae, and semispinalis dorsi et lumborum ; anteriorly with the spinalis dorsi. Action. — It is brought powerfully into play in kicking and rearing, by elevating the fore or hind quarters, according to whether the fore or hind limbs are fixed. Acting singly, the result is lateral flexion of the back and loins. It may assist also in expiration. SPINALIS DORSI.'"* Situated deeply on the withers, it is pyramidal in form, aponeurotic at its origin, with a fleshy belly ; it is with difficulty separated from the longissimus dorsi. Origin. — By aponeurosis from the supraspinous ligament, as far back as the twelfth, and from the posterior borders of the spinous processes of the six anterior dorsal vertebrae. Insertion. — To the superior spinous processes of the last three or four cervical vertebrae. Relation. — Externally with the trapezius and rhomboideus brevis ; anteriorly with the complexus major and splenius ; infe- riorly with the longissimus dorsi ; internally with its fellow, the ligamentum nuchas, the anterior dorsal vertebrae, and semispinalis dorsi. Action. — To assist in elevating the neck. SEMISPINALIS DOESI ET LUMBORUM. {Spinalis Transversus.) In contact with the dorsal and lumbar spines, this muscle con- sists of a number of fasciculi, whose fibres are directed upwards and forwards. Origin. — From the sacrum, the oblique processes of all the lumbar, and transverse processes of all the dorsal vertebrae. Insertion. — The spinous processes of the vertebrae, the fasciculi each passing over two or three spines before being inserted; it becomes continuous with the spinalis colli at the seventh cervical. * [Tliis muscle may be regarded as part of tlie longissimus dorsL— Ed.] 200 MYOLOGY. Relation. — Externally with the longissimus dorsi ; internally with the vertebrae. Action. — To assist in extending the spine. INTERTRANSVERSALES LUMBORUM. These are small muscular slips, invested by strong tendinous fasciae, running from the transverse process of one lumbar vertebra to the one adjacent. Relation. — "With the longissimus dorsi and intertransverse ligaments. Action. — To assist in flexing the spine laterally, by bringing these processes nearer to each other. Abdominal Region. The infero-lateral walls of the abdomen are formed by a large musculo-aponeurotic envelope, consisting of four pairs of muscles, covered externally by the abdominal tunic, the muscles on the right being separated from those on the left by the linea alba, a white fibrous cord extending from the sternum to the pubis. These muscles, the rectus excepted, consist each of a fleshy and an aponeurotic portion, and the general line of demarcation between the aponeurotic and the fleshy region is known as the linea semilvmaris. We have to describe the following structures : — Tunica abdominalis. Linea alba. Muscles. Obliquus abdominis externus. I Rectus abdominis, Obliquus abdominis internus, | Transversalis abdominis. TUNICA ABDOMINALIS. (Tunica Elasiica). The abdominal tunic is an immense expansion, composed of yellow elastic tissue, which covers the external oblique muscles. It is thickest at the pubis, and on each side of the linea alba, thinning as it approaches the sternum, and disappearing at the posterior attachment of the pectoralis magnus muscle. It blends with the external oblique, anteriorly reaching the digitations of ABDOMINAL REGION. 201 the serratus magnus ; posteriorly it furnishes a few fibres, which, detached from the surface of the common abdominal tendon (prepubian), pass between tne thighs, and become lost in the muscles of that region. Relation. — Externally by cellular tissue to the panuiculus and skin. It is continuous with the suspensory ligament of the sheath and dartos in the male, and the elastic envelope of the mamma in the female, in whom it is always thickest. Use. — To afford a mechanical support to the abdominal viscera, and conserve muscular action by substituting elasticity for it. On the application of distensile force it yields con- siderably. LINEA ALBA. The linea alba is a white fibrous cord situated between the inner borders of the two recti-abdominales, to which it gives attachment, as to the other abdominal muscles. Anteriorly it is attached to the inferior surface of the xiphoid cartilage, and posteriorly it becomes cenfounded with a large tendon, common to the abdominal muscles, the prepubian tendon, which is -attached to the anterior border of the pubis, and assists in the formation of the internal commissure of the inguinal canals. Between its posterior and middle third the linea alba is enlarged, and forms a lozenge-shaped space, in the centre of which is the remnant of the umbilicus. The fact of this structure joining the sternum to the pubic symphysis, together with certain co-related features, has induced anatomists to regard the linea alba as representing a rudimentary abdominal sternum. OBLIQUUS ABDOMINIS EXTERNUS. (Costo-abdominalis. ) (PL. XL 74.) The largest and most external muscle of the group, situated on the infero-lateral aspect of the abdomen, and consisting of a fleshy and an aponeurotic portion. It is quadrilateral, its fibres run- ning downwards and backwards. Its aponeurosis commences at a line called the linea semilunaris, and is continued to the linea alba, where it bends with that of the internal oblique. Attachments. — By fleshy fibres, anteriorly to the outer surface of the last thirteen or fourteen ribs, just below their middle ; the 202 MYOLOGY. four anterior digitations are received between the corresponding ones of the serratus maguus ; to the fascia of the latissimus dorsi^ and superiorly to the lumbar fascia : to the anterior iliac spine and crest ; to the pubis and prepubian tendon, and inferiorly to the linea alba throughout its whole extent. Relation. — Externally with the abdominal tunic ; antero- externally with the pectoralis magnus ; internally with the ribs, cartilages, and intercostals, the internal oblique and the rectus ; anteriorly with the serratus magnus. Action. — To support and compress the abdominal viscera, and assist in defecation, urination, and parturition. It is also a flexor of the vertebral column, and a muscle of expiration. APONEUROSIS OF THE OBLIQUUS EXTERNUS. The distribution of this aponeurosis being very singular and important, it merits separate consideration. It stretches from the anterior spine of the ilium to the pubis, answers to the fold of the groin, and marks the division between the trunk and hind extremity. Posteriorly it splits into two layers ; one descends internally over the thigh, forming the crural aponeurosis; the other is reflected upward, and enters the abdomina^ cavity, this fold receiving the name of the crural arch or Pouparfs ligament. JSTear the prepubian tendon, and immediately in front of its division, the aponeurosis is pierced by a large oval aperture, the external abdomival ring, which is the external opening of the inguinal canal. Crural Aponeurosis. This descends over the fold of the groin to the patella, and internal surface of the thigh, blending outwardly with the fascia lata, and internally becoming less dense in structure : it covers the sartorius. part of the gracilis, vastus internus, and the crural vessels as they leave the abdomen. Poupart's Ligament The Crural Arch or Pouparfs Ligament is a ribbon-shaped reflected portion of the aponeurosis of the external oblique, and is attached by its extremities to the anterior spine of the ilium, and anterior border of the pubis. Anteriorly it forms the posterior ABDOMINAL REGION. 203 pillar of the inguinal canal, and externally gives attachment to the posterior fibres of the internal oblique. Posteriorly it contacts the sartorius and pectineus muscles, and the crural vessels, embracing those parts in a sort of arch, hence its name. Its superior border at its external half is attached to the lumbo-iliac aponeurosis ; while its middle is confounded with the external surface of the sartorius and iliacus. Inside the attachments of the pectineus and psoas parvus, it forms, with the anterior border of the pubis, the iliacus and sartorius, a triangular open- ing called the crural ring, through which the crural vessels pass out of the abdomen. The inferior border is continuous with the femoral and great oblique aponeuroses. Inguinal Canal. The Inguinal Canal is infundibuliform and compressed laterally ; through it pass the spermatic cord and external pudic artery of the male, and mammary vessels of the female. It is situated obliquely between the crural arch, which is its posterior, and the internal oblique muscle, which forms its anterior wall. The external orifice is called the external abdominal ring, and is larger than the internal, being oval in fornv and directed backwards and inwards. It presents two pillars and two extremities or commissures. The pillars, anterior and posterior, are merely the edges or lips of the aperture, and are formed by the arciform fibres of the aponeurosis of the external oblique muscle, the posterior one being assisted by Poupart's ligament. The commissures, external and internal, are formed by the union of the pillars, the latter being limited by the prepubian tendon. The peritoneal or internal abdominal ring, the internal orifice of the canal, is situated in front of the crural ring. It is a mere dilatable cleft between the crural arch and the internal oblique, and but indifferently marked at its extremities. OBLIQUUS ABDOMINIS INTERNUS. (Ilio-abdominalis. ) (PL. III. 29.) Situated under the externus, on the postero-lateral and inferior aspects of the abdomen, its fibres expanding downvrards, it is, like the externus, fleshy and aponeurotic ; the fleshy portion is 204 MYOLOGr. thick, and occupies the flank ; the aponeurosis commences at the linea semilunaris, its fibres bknding with those .of the external oblique. Attachments. — Supero-posteriorly, to the anterior spine of the ilium, whence its fleshy fibres radiate ; a portion is attaqjied to the transverse processes of two or three of the first lumbar vertebrae, and passes to the posterior border of the last rib (this portion is described by the German anatomists as a retractor costce) ; and to the fascia of the latissimus dorsi ; to the cartil- ages of the false ribs ; postero-inferiorly to the symphysis pubis, by the prepubian tendon, aiding in the formation of the internal abdominal ring ; inferiorly to the linea alba throughout its whole extent. Relations. — Externally with the external oblique ; internally with the transversalis and rectus abdominis. Action. — It assists the externus in compressing the abdomen in the act of respiration, and in flexing the spine. It also draws the last rib backwards. RECTUS ABDOMINIS. (Steroio-pubialis. ) (Pl. III. 18.) Situated along the inferior and middle part of the abdomen, it is long, flat, polygastric, and broadest in the middle. Tendinous at its attachments, its belly consists of numerous flat muscular fasciculi, with transverse tendinous intersections, to which the aponeuroses of the oblique muscles are adherent ; these intersec- tions are called the linece transversce (inscriptiones tendinece), and may be regarded as the abdominal representatives of the ribs. The posterior part of the muscle assists in the formation of the internal abdominal ring. Attachments. — Anteriorly to the inferior surface of the xiphoid cartilage and sternum ; to the cartilages of the last four true and first two false ribs ; posteriorly to the crest of the pubis, through the medium of the prepubian tendon, which is directly continuous with it ; internally to the linea alba. Relations. — Inferiorly with the aponeurosis of the internal oblique muscle ; anteriorly with the pectoralis magnus ; superiorly with the transversalis, and the cartilages of nearly all the ribs ; internally with its fellow at the linea alba. SUBLIIMBAR REGION. 205 Action. — To support and compress the abdominal viscera and assist in respiration. It is the chief flexor of the spinal column. TRANSVERSALIS ABDOMINIS. (Lumbo-abdominalis. ) Placed on the infero-lateral aspect of the abdomen, imme- diately outside the peritoneum, this muscle is broad, flat, and quadrilateral, its fibres extending downwards. It is fleshy from its origin to the linea semilunaris, where it becomes aponeurotic. Attachments. — To the transverse processes of the lumbar vertebrae, and the inner surface of the cartilages of the false ribs, interdigitating with the attachments of the diaphragm, and by its aponeurosis to the xiphoid cartilage and linea alba, becoming rudimentary posteriorly. Relations. — Anteriorly with the diaphragm ; externally with the cartilages of the false ribs, the obliquus internus and rectus ; internally with a thin layer of fascia (the fascia transversalis) which connects it with the peritoneum. Action. — To assist the oblique muscles, and raise the viscera. SUBLUMBAR REGION". The muscles of this region, a single group, connect the lumbar and last dorsal vertebrae with the pelvis or the posterior limb. They are covered by the iliac fascia, and this by the peritoneum, a serous membrane lining the abdominal cavity. In this group we place four muscles : — Psoas magnus. I Iliacus. Psoas parvus. | Quadratus lumborum, PSOAS MAGNUS. {Sublumbo-trochantineus.) (Fig. 76. c.) Situated below the transverse processes of the lumbar vertebrae, it is elongated and fusiform, flattened anteriorly, conical posteriorly, its ■ fibres extending downwards and backwards ; it is almost entirely fleshy, except at its insertion. Origin. — From the inferior surfaces of the last two ribs, the 206 MYOLOGY. bodies of the last two dorsal, and all the lumbar vertebrae except the last, and to the lumbar transverse processes, passing between the two parts of the iliacus. Insertion. — By a tendon, common to it and the iliacus, to the internal trochanter of the femur. Relation. — Posteriorly with the iliacus ; internally with the psoas parvus and the bodies of the vertebrae; above with the Fia. 76. Muscles of the sublumbar and internal deep femoral regions— seen from below, a, a. Quadratus lumborum ; 6, Psoas parvus ; c, Psoas magnus ; d. e, Iliacus ; /, Pectineus ; g, Adductor brevis ; h, Adductor longus ; i, Adductor magnus ; fc, Vastus internus : I, Kectus femorls. quadratus lumborum, and below with the kidney and iliac fascia, the diaphragm, and, in the thoracic cavity, with the pleura. Action. — To flex and rotate the thigh, or, the latter being fixed, to flex the loins ; the latter action tends to " roach " the back,' PSOAS PARVUS. {Suhlumho-puhialis. ) (Fig. 76. 6.) Situated on the inner side of the psoas magnus, it is long, thin, and semipenniform, the fibres extending backwards and outwards. SUBLUMBAR REGION. 207 Tleshy above, it has posteriorly a strong flat tendon passing along the lower surface to its insertion. Origin. — From the bodies of the last three or four dorsal, and all the lumbar vertebras. Insertion. — To the ilio-pectineal eminence on the brim of the pubis, midway between the symphysis and the acetabulum, and to the iliac fascia. Relation. — Inferiorly with the diaphragm, pleura, posterior aorta and vena cava ; externally with the psoas magnus. Action. — To flex the pelvis on the ppine, when the loins are fixed ; when the pelvis is fixed, to arch the back. It is also the tensor of the iliac fascia. ILIACUS. (Ilio-trochantineus.) (Fig. 76. d, e.) Situated under the false pelvis, this muscle is strong, thick, -and pyramidal, the base being forwards, and the fibres extending downwards, backwards, and inwards. The belly is incompletely divided by a fissure into two unequal portions, the external being the larger; through this fissure passes the tendon of the psoas magnus, which its own tendon joins. Origin. — From the ilio-pectineal ridge, nearly all the venter surface of the ilium, and the inferior sacro-iliac ligament. Insertion. — To the internal trochanter of the femur, along with the psoas magnus. Relation. — Superiorly with the ilium ; inferiorly with the iliac fascia and sartorius ; externally with the tensor fasciae latse and rectus femoris, from which it is separated by a layer of fat ; internally with the crural vessels. It passes between the vastus internus and the pectineus. Action. — To flex the femur, and rotate it outwards. QUADRATUS LUMBORUM. {Sacro-lumbalis. ) (Fig. 76. a.) Placed below and between the lumbar transverse processes, this is a flat, thin muscle, consisting of several bundles, with strong tendinous intersections. The principal bundle is situated exter- 208 MYOLOGY. nally and longitudinally, the lesser ones diverging from it inwards- and forwards, Oingin. — The chief bundle arises from the inferior sacro-iliac ligament at the angle of the sacrum, passing directly forwards. Insertion. — To the posterior border of the last rib, becoming attached in its course to the free extremities of the transverse processes of the lumbar vertebrae. The other bundles leave the internal border of the first, and are attached to most of the trans- verse processes of the lumbar vertebrae, and inner surfaces of the last two or three ribs. Relation. — Superiorly with the vertebrae, and intertransversales liimborum ; inferiorly with the psoas magnus. Action. — To assist in lateral flection of the lumbar vertebrae, and to draw the last ribs backwards. Diaphragmatic Region. This region contains only one muscle, from which it takes it» name. DIAPHRAGM. (Diaphragma.) (Fig. 77. A.) The diaphragm, or midrif, is the muscular partition whiob separates the thorax from the abdomen ; it slopes obliquely down- wards and forwards, and is in form elliptical, or somewhat heart- shaped, being widest superiorly. The thoracic surface is convex and covered with pleura, the abdominal concave and covered with peritoneum. It is divided into a body or septum, and two crura or appendices ; the body, or greater muscle, is made up of a fleshy periphery and tendinous phrenic centre (Speculuvo Helmontii). Attachments. — The fleshy portion is attached to the inner surface of the distal ends of the last twelve ribs, or to their cartilages, and to the superior surface of the ensiform cartilage, the fibres converging towards the tendinous centre. The crura ot pillars, two in number, lie below the vertebrae in the sublumbar region. The right is the longer and larger, and arises from tho inferior surface of the bodies of all the lumbar vertebrre but the last, by strong tendinous fibres which blend with the inferior common ligament. The left differs from the right in arising from only one or two anterior lumbar vertebrae. The crura pass DIAPHRAGMATIC REGION. 209^ down the central line of the tendinous portion, and gradually blend with its fibres. Near the centre- of the diaphragm, and a little to the right, is a large opening, the foramen dextrum^ through which passes the posterior vena cava. Between the pillars superiorly is a second opening, the hiatus aorticus, through which pass the posterior aorta, vena azygos, and thoracic duct. Below this, the right crus forms towards the left a third opening, the foramen sinistrum, for the passage of the oesophagus and pneumogastric nerves, accompanied by the pleural artery. There Fig. 77. The diaphragm, and superficial muscles of the internal femoral region— viewed from belowr A, The diaphragm ; a a, The tendinous centre ; a' a'. The fleshy periphery; a" a"i The crura; a'", The hiatus aorticus ; a"". The foramen sinistrum ; a""'. The foramen dextrum ; &, The sar- torias ; c, The gracilis. are thus three openings — the hiatus aorticus above, the foramen sinistrum in the middle, and the foramen dextrum below. Certain of the sublumbar muscles originate partly in the thorax, and the diaphragm forms arches which allow their passage, and that of the sjonpathetic and splanchnic nerves ; these arches are bouiided by ligaments, the ligamenta arcuata ; outside the arches, the diaphragm is attached to the last rib by a broad fold ot elastic tissue. Relation. — Anteriorly with the pleura, which covers Doth it p 210 MYOLOGY. and the lungs ; posteriorly, covered by peritoneum, it contacts the liver, stomach, spleen, and the large colon. Action. — Essentially a muscle of inspiration. When it eon- tracts it becomes flattened, forces the abdominal viscera back- wards, and so enlarges the thoracic cavity. This action is antagonistic to one of the actions of the abdominal muscles. It also assists in the expulsive efforts of defecation and parturition. Coccygeal Kegion. The muscles of this region, that of the tail, are enclosed in strong fascia, which may be said to be continuous with the approximate pelvic ligaments. We find one group containing four muscles : — Erector coccygis. I Curvator coccygis. Depressor coccygis. I Compressor coccygis. ERECTOR COCCYGIS. {Sacro-coccygeus Superior.) (Pl. IIL31.) Situated on the supero-lateral part of the tail, it consists of bundles of fibres, intersected by tendons, which gradually diminish in size from before backwards, each terminating in a short tendon. Origin. — The tuberous summits and lateral aspect of the posterior sacral spines, and superior surface of the coccyx. Insertion. — To the coccygeal bones. Relation. — Internally with its fellow, and the coccygeal verte- bra ; externally with the skin and fascia. Action. — When acting together to elevate the tail; singly, to draw it upwards and outwards. DEPRESSOR COCCYGIS. (Sacro-coccygeus Inferior.) (Pl. in. 33.) Situated on the infero-lateral aspect of the tail, and similar to the erector, but thicker. Origin. — Within the pelvis, from the inferior surface of the sacrum, the inner surface of the sacro-sciatic ligament, and the -coccygeal vertebrae. MUSCLES OF THE LIMBS. 211 Insertion. — By tendons to the inferior surface of all the coccygeal vertebrae successively. Relation. — Superiorly with the sacrum, coccyx, and curvator ; ioferiorly with the rectum ; externally with the curvator and sacro-sciatic ligament ; internally with its fellow. Action. — To bend the tail downwards ; singly, to draw it downwards and to one side. CURVATOR COCCYGIS. {Sacro-coccygeus Lateralis.) (PL. IIL 32.) Situated on the side of the tail, and similar in structure to the preceding, it is merely a continuation of the semispinalis lumborum. Oricfin. — From the spines of the last lumbar, and lateral aspect of the sacral and coccygeal vertebrae. Insertion. — The side of the coccyx, between the erector and depressor. Relation. — Superiorly with the erector and sacral ligament; inferiorly with the depressor ; externally with the compressor. Action. — To curve the tail, drawing it sideways over the quarter. COMPRESSOR COCCYGIS. (Ischio-coccygeus. ) Situated at the side of the pelvis, it is a large, thin, and tri- angular muscle. Origin. — By aponeurosis, from the superior ischiatic spine and the inner surface of the sacro-sciatic ligament, running upwards and backwards. Insertion. — By fleshy fibres, to the side of the terminal sacral and first two coccygeal vertebras. Relation. — Externally with the sacro-sciatic ligament ; inter- nally with the curvator and rectum. Action. — To depress the entire tail. Muscles of the Limbs. The muscles of this class are those which are specially related to the limbs, for the most part acting upon them alone ; they arc intrinsic aud extrinsic, according to their origin. These muscles 212 MYOLOGY. are either flexors^ extensors, abductors, adductors, or rotators, but in the horse the last are comparatively few, limited in their action, and nearly all extrinsic, the joints of the horse's limhs below the shoulder and hip allowing very slight rotatory motion. Muscles of the Pectoral Limb These may be conveniently divided Scapular , Brachial . Antibrachial Metacarpal nto the following regions :- The shoulqler. The arm. The fore-arm. The foot (hand). Scapular Region. Externally the region is covered by the strong scapular fascia, and comprises an external group of four and an internal of three muscles. External Scapular Group. Teres externus. f Postea-spinatus. Antea-spinatus. I Postea-spinatus minor. TERES EXTERNUS. (Scapulo-humeralis Magnus.) (Fig. 78. c.) This is the long abductor of the arm, which corresponds to the deltoid of man. Situated on the outer and posterior part of the shoulder, it consists of two portions, anterior and posterior. The posterior or larger portion is triangular in form, and very fleshy, the fibres extending obliquely downwards and forwards; it is lodged in a depression in the caput magnum. The anterior or superior portion is thin, and aponeurotic above, extending over the postea-spinatus muscle, to which it is adherent. Attachments. — The posterior section arises from the dorsal angle and posterior costa of the scapula ; the anterior by strong fascia from a tubercle on the spine of the scapula, and the scapular fascia. They unite inferiorly, and by tendinous and fleshy fibres are inserted to the deltoid ridge of the humerus below the insertion of the postea-spinatus minor. EXTERNAL SCAPULAR GROUP. 213 Jielat ion. — Anteriorly Avtth the ca^put magnum, caput medium.and postea- spinatus; externally with the scapular fascia, A dion . — To abduct the humerus, and rotate it outwards; when acting with the teres internus to flex the shoulder joint. with the postea-spinatus ; internally ANTEA-SPINATUS. XSaperacromio-trochiterius.) (Fig. 78, a.) Occupying the antea- ?pinatus fossa of the scapula, this muscle is pjTamidal in shape, with the base downwards. Its fleshy fibres extend ob- liquely forwards; then be- coming tendinous infer- iorly, it is bifurcated for the passage of the flexor brachii tendon, the divi- sions being connected by aponeurosis. Origin. — From the anterior fossa, anterior costa, and cervical angle of the scapula, and the anterior surface of its spine. Insertion. — By two parts, one external, to the summit of the exter- „ , , .^ . • ,. ^ . , . Muscles of the anterior limb— external view, a, Antea- nal trochanter, and one splnatos ; 6, Postea-spInatus ; c, Teres extemus ; d. Caput intprnal +n tliP «iiTYimit «>agnum ; e. Caput medium ;/, Flexor brachii ; jr, Extensor luueiudl, to xne summit metacarpimagnus; ft, Extensor metacarpiobUquus:i,Flexor of the internal trochanter, metacarpi extemus ; fc. Extensor pedis ; fc', Its tendon ; fc" n ,1 1 Fibrous band from the suspensory ligament ; I, Extensor Ot the humerus. suffraginis = V, its tendon. Fig. 78. 214 MYOLOGY. Relation. — Externally with the scapular faScia; anteriorly with the pectoralis parvus ; posteriorly with the scapular spine and the anterior border of the postea-spinatus ; internally with the bone ; antero-inferiorly with the levator humeri and the tendon of the flexor brachii. Action. — To extend the humerus on the scapula, and tense the fascia covering the flexor brachii. It serves, like the other- scapular muscles, as an active ligament of the shoulder joint. POSTEA-SPINATUS. {Subacromio-trochiterius. ) (Fig. 78. 6.) Lodged in the postea-spinatus fossa, it is broad, flat, and' triangular, with the apex below, to which its fibres converge ; it is fleshy, with strong tendinous intersections. Origin. — From the posterior costa and fossa of the scapula, the posterior border of its spine, and the cartilage of prolongation Insertion. — By two divisions, one of which goes to the inner side of the convexity of the external humeral trochanter ; the other, a strong tendon, passes over the trochanter, and is inserted to a roughened ridge below. Between the tendon and convexity is a synovial bursa. Relation. — Externally with the aponeurosis of the teres ex- ternus and with the scapular fascia ; anteriorly with the antea- spinatus and the scapular spine ; posteriorly with the teres extemus; internally with the scapula, its cartilage, and the postea-spinatus minor ; inferiorly it contacts the capsular ligament of the shoulder, joint. Action. — To abduct the humerus, and rotate it outwards. POSTEA-SPINATUS MINOE. (Scapulo-humeralis Parvus.) (Fig. 80. a a.) Situated on the inside of the teres extemus, below the postea- spinatus, and along the posterior border of the scapula, it is long and prismatic inferiorly, fleshy, and intersected by tendon, and is easily divided into a large and small portion. Origin. — From the posterior border of the scapula, and by INTERNAL SCAPULAR GROUP. 215 tendinous slips from the posterior fossa, and a small tubercle on the external side of the rim of the glenoid cavity. Insertion. — To the deltoid ridge. Relation. — Externally with the teres externus and postea- spinatus ; internally with the caput magnum, caput medium, and capsular ligament. Action. — Like the last, to abduct, and rotate the humerus outwards. Internal Scapular Group. Subscapularis. Teres internus. Scapulo-humeralis posticus. SUBSCAPULARIS. (Subscapulo-trochineus. ) (Fig. 79. a.) Situated on the inner side of the shoulder blade, occupying the subscapular fossa, it is fan-shaped, forming three points supericriy, ita fibres converging downwards. It is covered by strong fascia, from which arises the subscapulo-hyoideus. Origin. — From the whole of the subscapular fossa. Insertion. — To the internal humeral trochanter, by a strong ten- don passing over its summit, where there is a small synovial bursa. Relation. — Externally with the scapula; internally with the serratus magnus ; anteriorly with the antea-spinatus, with which it blends, the two forming a space through which passes the pre- scapular artery ; posteriorly with the teres internus. Action. — To adduct the arm, and perhaps to rotate it slightly inwards. TERES INTERNUS. (Teres Major — Suhscapulo-humeralis. ) (Fig. 79. b.) This, an adductor of the arm, is situated just behind the sub- scapularis, at the posterior border of the scapula ; it runs obliquely downwards, corresponding to the terres externus. It is elongated, wide in the middle, tapering at the extremities, its posterior edge being thin. Origin. — From the dorsal angle and posterior costa of the scapula. 216 MYOLOGY. Insertion. — By a flat tendon, which joins that of the latissi- mus dorsi, to the internal tuberosity of the humerus, between the tendons of in- sertion of the coraco-humeralis. Relation. — Postero- externally with the fascia of the latissimus dorsi and scapulo-ulnaris ; anteriorly with the sub- scapularis ; internally with the serratus magnus; inferiorly with the coraco- humeralis and humeralis obliquus. Action. — To ad duct, and rotate the humerus inwards ; acting with the teres externus the result is flexion. SCAPULO-HUMERALIS POSTICUS. (Scapulo-humeralis Gracilis — Grele. ) Situated behind the shoulder joint, between the caput magnum and the cap- sular ligament, it is very small, slender, and fusiform, with a pale, delicate, fleshy belly, and tendinous extremities. Origin. — From the postero-inferior part of the scapula, just above the glenoid cavity, and the capsulaT ligament of the shoulder joint. Insertion. — Between the fibres of the humeralis obliquiis, to the posterior part of the humerus, just below its head. Action. — To render tense the capsular ligament of the joint, and thus prevent its being crushed during flexion ; this action was ascribed to it by Rigot, who was the first to describe it. It is believed to be peculiar to the solidun- gula. Fig. 79. Muscles of the anterior limb- internal view, a, Subscapularis; b. Teres intemus ; c, Coraco- hnmeralis; d, Scapulo-ulnaris; e. Flexor metacarpi intemus; f. Flexor metacarpi medius; g, .Caput parvum. Brachial Region. This region clothed by the brachial fascia, includes the muscles which cover the humerus and its vicinity; they consist of an. ANTERIOR BRACHIAL GROUP. 217 anterior and a posterior group, the former being mostly anterior or lateral to the bone, the latter situated behind it, In either ^roup we find three muscles. Anterior Brachial Group. Flexor brachii. Coraco-humeralis. Humeralis obliquus. FLEXOR BRACHII. (Coraco-radialis.) (Fig. 78. /.) The analogue of the biceps in man, this muscle is situated in front of the humerus : it is long and cylindrical, passing down- wards and backwards. The tendon of origin contains fibro-cartilage, and the belly is intersected by tendinous fibres. Origin. — From the base of the coracoid process of the scapula, l)y a strong tendon, which passes over the bicipital groove where there is a synovial bursa. InseHion. — By a short tendon to the bicipital tuberosity on the antero-internal part of the head of the radius, and to the capsular ligament of the elbow joint ; a part of it passes under the internal-lateral ligament of the elbow joint. A strong fibrous band is given off inferiorly which joins and expands over the extensor metacarpi magnus, and becomes blended with the anti- trachial fascia. Relation. — Anteriorly with fascia, covered by the levator humeri ; internally with the coraco-humeralis; posteriorly with the humerus; superiorly its tendon passes between the two insertions of the antea-spinatus, where a strong fascia envelopes it and is tensed by the last-named muscle. Action. — To flex the radius on the humerus, extend the latter on the scapula, and to tense the antibrachial fascia. A band of unyielding tendinous material runs through this muscle, enabling it to act as a ligament, and passively support the shoulder joint, when the animal is at rest ; the band joining the extensor metacarpi also relieves muscular tension. 218 MYOLOGY. CORACO-HUMERALIS. Omo-hrachialis. (Fig. 79. c.) Situated on the inner side of the humerus, this muscle is ten- dinous, long, and fusiform, its fibres passing obliquely downwards. Attachments. — From the beak of the coracoid process of the scapiila. Passing between the subscapularis and the antea- spinatus, the tendon is succeeded by two fleshy bellies, a super- ficial and a deep one. The latter, thin and short, is inserted to the shaft of the humerus just above its internal tuberosity ; the former, by far the larger, is inserted to a rough surface on the same bone, lower down, and more anteriorly. Relation. — Anteriorly with the flexor brachii ; superiorly with the antea-spinatus and subscapularis ; internally with the pector- alis magnus ; posteriorly with the latissimus dorsi and teres internus, whose tendons pass between its two bellies. Action. — To extend, adduct, and rotate the arm inwards. HUMERALIS OBLIQUUS. {Humero-radialis — Brachialis A nticus. ) (Fig. 80. d.) Occupying the musculo-spiral groove, it is flat, oblong, wide superiorly, and almost entirely fleshy ; it covers successively portions of the posterior, external, and anterior surfaces of the humerus, terminating on the inner aspect of the radius. Origin. — From the postero-superior part of the shaft of the humerus, just below the articular head, winding round the bone under the external tuberosity. Insertion. — To a ridge on the inner part of the head of the' radius, after passing through a transverse groove just below, and within the insertion of the flexor brachii ; also to the ulna, passing imder the internal-lateral ligament of the joint, and blending with the arciform ligament. Relation. — Externally with the caput magnum and caput medium ; internally with the humerus ; anteriorly with the flexor brachii. Action. — Solely to flex the elbow joint. POSTERIOR BRACHIAL GROUP. 219 Posterior Brachial Group Scapulo-ulnaris. Triceps extensor brachii. Anconeus. scapulo-ulnaris. {Scapulo-olecranius Longus.) (Fig. 79. d.) Situated on the postero-internal aspect of the region, adhering to the caput magnum, this is a broad and flat muscle, aponeurotic at its origin, with a fleshy belly, and divisible into an anterior and posterior portion. Origin. — Aponeurotic, from the dorsal angle and posterior costa of the scapula. Insertion. — To the inner part of the apex of the olecranon, and to the antibrachial fascia. Relation. — Externally with the caput magnum; anteriorly with the caput medium ; internally with the pectoralis magnus ; superiorly with the latissimus dorsi. Action. — To flex the shoulder joint, extend the elbow joint, and tense the antibrachial fascia. triceps extensor brachu. {Triceps Brachii.) (Fig. 78. d, e.) A very large and powerful muscle, occupying the space between the posterior border of the scapula, the humerus, and the olecranon. It consists of three parts, which have different origins, but a common insertion to the olecranon process. We describe them as if they were separate muscles, under their respective Caput magnum. Caput medium. Caput parvum. 220 MYOLOGY. CAPUT MAGNUM. {Scnpulo-olecranius Magnus.) (Fig. 78. d.) This, the great extensor of the fore-arm, is situated on the posterior aspect of the shoulder. It is thick and triangular, extending obliquely downwards and backwards, and consists of several bundles, with tendinous intersections. Origiv. — From the dorsal angle and posterior costa of the scapula. Insertion. — By a strong tendon to the inner and upper part of the olecranon, a synovial bursa being interposed between it and the apex. It receives many fibres from the caput medium. Relation. — Externally with the fascia, the panniculus carnosus,, and the teres externus, which occupies a depression in it ; inter- nally with the latissimus dorsi, scapulo-ulnaris, and teres internus; inferiorly with the caput medium and caput parvum. Action. — To flex the shoulder joint, and extend the fore-arm. CAPUT MEDIUM. (Ihimei'o-olecranius ExtermLS.") (Fig. 78. e.) Placed between the preceding niuscle and the humerus, it is thick, short, and fleshy, extending obliquely backwards and down- wards. Origin. — Aponeurotic, from a ridge on the supero-posterior part of the shaft, of the humerus, running from the deltoid ridge to the neck. Insertion. — The supero-posterior part of the olecranon ; or it may join the tendon of the caput magnum. Relation. — Superiorly with the caput magnum ; externally with the teres externus ; inferiorly with the humeralis obliquus and extensor metacarpi magnus; internally with the caput parvum. Action. — To extend the fore-arm. ANTIBRACHIAL REGION. 221 CAPUT PARVUM. (Bumero-olecranius Internus.) (Fig. 81. a.) Placed on the inner and mesiau portion of the shaft of the humerus, along the inferior border of the caput magnum, this muscle is slender and triangular, with a fleshy origin. The fibres pass obliquely backwards and downwards, terminating in two flat tendons. Origin. — From the postero-internal part of the middle third of the humerus, extending from the inner tubercle. Insertion. — To the inner part of the apex of the olecranon, one tendon passing over a small groove before its insertion, Avhich is situated below the other one. Relation. — Superiorly ' with the caput magnum ; externally with the humerus, humeralis obliquus, and caput medium ; in- ternally with the insertion of the coraco-humeralis, with the teres internus, latissimus dorsi, and scapulo-ulnaris. Action. — To extend the fore-arm. ANCONEUS. {Humero-olecranius Parvus.) (Fig. 80. e.) Situated at the back of the elbow joint, it is small, thick, and almost entirely fleshy, filling up the space between the condyles of the humerus, or the olecranon fossa. Origin. — From the borders of the fossa, chiefly the epi trochlea, and the capsular ligament of the elbow joint. Insertion. — The antero-extemal part of the olecranon. Relation. — Posteriorly with the caput medium muscle ; ante- riorly with the elbow joint and humerus. Action. — To tense the capsular ligament, and prevent it from being crushed during extreme extension. ANTIBRACHIAL REGION. The muscles of this region, the fore-arm, cover the ulna and radius, except on the inner aspect of the latter, where there is little interposed between the skin and the bone ; they are divided into 222 MYOLOGY. two distinct groups, tlie anterior and posterior, tlie first of wliich are all extensors, the second all flexors. All these muscles are inserted below the radius, and therefore act upon the carpus or on the joints below. The region is enclosed in the antibrachial fascia, an exceedingly strong covering, which is firmly attached to the radius and ulna. Anterior Antibrachial Group. extensors. The extensor group includes four muscles : — Extensor metacarpi magnua. ] Extensor pedis. Extensor metacarpi obliquus. | Extensor suflfraginis. EXTENSOR METACARPI MAGNUS. (Epicondylo-premeiacarpeus. ) (Fig. 78. g.) Situated in front of the radius, and in figure pyramidal, extend- ing downwards, it consists of a fleshy belly, and a long flat tendon, which commences at about the lower third of the radius, and passes over the carpus, terminating at the head of the meta.carpus. Origin. — From the epitrochlea, or ridge above the external condyle of the humerus, from the capsular ligament of the elbow joint anteriorly, and the surface just above. It receives a strong tendinous band from the flexor brachii. The tendon passes through a groove or theca in the anterior part of the distal end of the radius, where there is a synovial sheath or bursa, then over the knee through a second synovial apparatus. Two synovial sheaths are thus interposed betv/een the bones and the tendon, the latter being bound down by the anterior annular ligaments, and by the tendon of the extensor metacarpi obliquus, which crosses it in an oblique manner just above the carpus. Insertion. — To a tuberosity^ on the anterior part of the head • of the great metacarpal bone, towards its inner side. Relation. — Anteriorly with the fascia ; posteriorly with the radius ; externally with the extensor pedis ; supero-internally with the humeralis obliquus and flexor brachii ; inferiorly with the extensor obliquus. Action. — To extend the carpus. ANTERIOR ANTIBRACHIAL GROUP. 223 EXTENSOR METACAEPI OBLTQUUS. (Badio-premetOfCarpeus. ) (Fig. 78. h.) This muscle is situated on the infero- anterior part of the radius, and is tri- angular and penniform ; aponeurotic above, it terminates in a small tendon, which crosses obliquely the inferior extremity of the anterior surface of the radius, under the extensor pedis, and over the extensor metacarpi magnus tendon. Origin. — From the external border of the radius. Its tendon passes through the oblique groove on the antero-internal part of the distal end of the radius, where there is a synovial sheath. Insertion. — The head of the inner metacarpal bone. Relation. — Anteriorly with the ex- tensor pedis and the fascia ; posterior- ly with the extensor metacarpi magnus and the bone. Action. — To extend the metacar- pus, and rotate it slightly, carrying the inner aspect forwards. EXTENSOR PEDIS. (Bpitrochleo-prephalangeus. ) (Fig. 78. Jc; Fig. 80./.) Placed on the antero-external part of the fore-arm, it is long and pyra- midal, extending downwards ; fleshy above, its belly is bifid inferiorly, and terminates in a long tendon, which is double, and commences about the inferior third of the radius. Fig. 80. External view of the muscles of the anterior limb— showing the deeper ones of the upper region, aa, Postea- spinatus minor ; b, Deep portiop of postea-spinatus ; c, Flexor brachii divided, and the upper part raised ; c'. Its tendon, which fits the bicipital groove ; d, Humeralis obliquus ; e, An- coneus ; /, Extensor pedis ; g, Thier- nesse's muscle ; h, Phillips' muscle ; h'. Its tendon. 224 MYOLOGY. Origin. — The fleshy part arises from the base of the epitrochlea^ and the anterior border of the external lateral ligament of the elbow joint, the front of the distal extremity of the humerus, and the outer part of the head of the radius. The tendon, which is double, passes through a synovial theca in the external groove on the distal end of the radius, under the anterior annular ligament. Below the knee it sends a small tendon to join that of the extensor suffraginis ; then expanding, it passes over the front of the fetlock joint, being attached to the capsular ligament, and having a small synovial bursa interposed ; below the fetlock it receives on either side a strong slip from the suspensory ligament, and it becomes attached to the anterior part of the first and second phalanges. Insertion. — To the pyramidal process of the os pedis. Relation. — Anteriorly and externally it is covered by the fascia ; posteriorly related with the extensor suffraginis, the radius, carpus, metacarpus, and phalanges ; internally with the extensor metacarpi magnus. Action. — To extend the phalanges on each other, and assist in extending the carpus. If the tendon which joins that of the extensor suffraginis be carefully traced upwards, it will be found to be continuous with a long thin muscle separable from the extensor pedis, and placed along its postero-extemal aspect ; it arises from the external lateral ligament of the elbow joint and the corresponding tuber- osity pf the radius, and has received the name of Phillips' muscle (Fig. 80. h). Somewhat anteriorly to the above a still smaller muscle may be found arising from the external arciform ligament, and terminating in a small tendon, which joins that of the extensor pedis a short distance above the carpus ; this has been called Thiernesse's muscle (Fig. 80. g). These two muscles are not generally described, but are regarded as forming a part of the extensor pedis. EXTENSOR SUFFRAGINIS. (Eadio-prephalangetis.) (Fig. 78. 1.) Situated on the external part of the fore-arm, between th» extensor pedis and the flexor metacarpi externus, this muscle is semipenniform, consisting of a flattened fleshy belly, enveloped in POSTERIOR ANTIBRACHIAL GROUP 225 a strong aponeurotic sheatb, and having its edge turned outwards. The belly ends in a round tendon, which passes through a theca in the vertical groove on the external side of the distal end of the radius, and down the external aspect of the carpus, reaching the anterior surface of the large metacarpal boue. Origin. — From the external part of the head of the radius, the external lateral ligament of the elbow joint, the shaft of the radius, and the lateral aspect of the ulna. Insertion. — To the head of the os sufifraginis, related also with the capsular ligament of the fetlock joint. Below the knee it is joined by two tendinous slips, one from the tendon of the extensor pedis, the other, a species of check ligament, from the trapezium. Relation. — Anteriorly with the extensor pedis ; posteriorl}* with the flexor pedis perforatus, the perforans, and flexor meta-- carpi externus ; externally with the fascia. Action. — To extend the digit, and assist the extensor pedis. Posterior Antibrachial Group. FLEXORS. This, the flexor group, consists of seven muscles, three flexors of the carpus, and four flexors of the digit : — Flexor metacarpi externus. Flexor metacarpi medius. Flexor metacarpi internus. Flexor pedis perforatus. Flexor pedis perforans Ulnaris accessorius. Radialis accessorius. FLEXOR METACARPI EXTERNUS. (JUpitrochleo-carpeus. ) (Fig. 78. i.) Situated on the postero-external aspect of the fore-arm, this muscle is elongated and flattened, the fleshy belly being inter- sected by strong, tendon. Origin. — By a very short strong tendon from the summit of the epitrochlea of the humerus, terminating in two tendons ; the anterior, longer, and more delicate, passes through a synovial theca, in a groove on the external surface of the trapezium. Insertion. — The anterior tendon goes to the head of the outer splint bone ; the posterior, short and flat, becomes inserted to the Q 226 MYOLOGY. superior part of the trapezium, blending with the flexor meta- carpi medius. Relation. — Externally with the fascia ; internally with the flexor pedis muscles and the flexor medius ; anteriorly with the extensor suffraginis. Action. — To flex the carpus. FLEXOR METACARPI MEDIUS. (Flexor M. Obliquus — Epicondylo-carpeus.) (Fig. 79./.) Similar in structure to the preceding muscle, it is situated on the postero-internal part of the radius, extending downwards and outwards. It is long, flat, and bifid above ; one head is small, the other large and fleshy. Origin. — The large head arises from the epicondyle, the small Tiead from the posterior surface of the olecranon ; they unite at a short distance down the radius. Insertion. — By one tendon to the supero-posterior and inter- nal part of the trapezium, blending with the extemus. Relation. — Externally with the fascia ; internally with the flexors bf the foot ; anteriorly with the flexor intemus ; posteriorly with the flexor externus. Action. — To assist the preceding muscle in flexing the carpus. FLEXOR METACARPI INTERNUS. {Epicondylo-metacarpeus. ) (Fig. 79. e.) 'Situated on the internal aspect of the fore-arm, it resembles 'the two preceding muscles in its structure, being long and flattened, with a fleshy belly, but having a long tendon of insertion. Origin. — By tendinous fibres from the base of the epicondyle just by the medius. InseHion. — To the head of the inner splint bone, the long round tendon passing through a synovial theca on the inner side of the carpus. Relation. — Externally with the fascia ; internally with the chief radial vessels and nerves, and the flexors of the foot ; anteriorly with the radius ; posteriorly with the medius. Action. — Like the preceding, to flex the carpus. POSTERIOR ANTIBRACHIAL GROUP. 9.-27 FLEXOR PEDIS PERFORATUS. {Flexor Sahlimis — Epicondylo-phalangeus. ) (Fig. 81. h.) Situated in the posterior region of the fore-arm, under the flexors of the carpus, this muscle is -long, thin, and prismatic, its belly being fleshy, with tendinous intersections, and extending almost to the carpus, where it is succeeded by a long tendon, which passes through a synovial sheath behind the joint, closed in by the posterior annular ligament. Above the carpus, the tendon is joined by a broad band of fibrous tissue, called the superior carpal or superior " check " ligament, which springs from the infero-posterior surface of the radius, being also attached to the antibrachial fascia, and usually to the perforans muscle ; below the knee, the tendon assists in the formation of a synovial sheath for the tendon of the flexor perforans. At the fetlock it ex- pands and forms a ring or sheath, through which passes the perforans tendon, hence the names perforans and perforatus; below the pastern joint the tendon divides into two. Origin. — From the summit of the epi- condyle, by a tendon common to it and the perforans. Insertion. — To the projecting lateral parts of the os corona?. Relation. — Posteriorly with the flexor metacarpi externus and medius ; anteri- orly with the perforans. Two important synovial sheaths or canals are related with this and the perforans tendon, the carpal and the metacarpo-phalangeal. The first, to which is attached the antibrachial fascia, is formed by the posterior Fio. 81. Internal view of the deep muscles of the anterior limb, a, Caput par-, vum of triceps extensor brachii ; &, Flexor pedis perforatus ; 6', Its tendon ; 6" V", Slips to the phal- anges ; c c, Flexor pedis perforans ; c', Radialis accessorius ; c", Ulnaris accessorius ; c'", Inferior check liga- ment ; d, Perforans tendon leaving the sheath of oerforatus tendon. 228 MYOLOGY. carpal and annular ligaments ; the second is formed by the car- tilaginous pad clothing the great sesamoid bones, the posterior face of their' inferior, and their annular ligaments, the latter being very, adherent to the perforatus tendon, which it covers, and is continued both upwards and downwards, being attached to the phalanges by three fibrous bands on each side. The synovial membranes lining these sheaths, and reflected on the tendons, are very large, and project considerably above and below, each forming an upper and a lower cul-de-sac ; the lower one of the sesamoidean sheath reaching that formed by the mem- brane of the coffin joint, and also the superior one of the navicular sheath. Action. — To flex the pastern and fetlock joints, and assist in flexing the carpus. The superior check ligament enables it to act as an unyielding brace to the joints below during rest. FLEXOR PEDIS PERFOEANS. {Flexor-Profundus — Ejncondylo-phalangeus. ) (YiG. 81. c c.) This muscle is situated between the preceding one and the radius ; it is long, tendinous at its origin, with a round fleshy belly, much larger than that of the perforatus, and ending, above the carpus, in a funicular tendon. This tendon passes through the posterior carpal sheath, then through a sheath partly formed by the perforatus tendon below; it is joined by the tendons of the accessory flexors, and half-way down the metacarpus by the inferior carpal or check ligament, a strong fibrous band which is continuous 'with the posterior carpal ligamemt. The tendon then passes through the sesamoidean sheath anteriorly to the per- foratus tendon, and then between the terminal slips of the latter, over the supero-posterior part of the os coronse, when it expands, the expanded part being termed the plantar aponeurosis; it passes thence over the navicular bone, and its synovial capsule, to the solar aspect of the pedal bone. Origin. — In common with the perforatus from the epicondyle. Insertion. — To the semilunar ridge on the solar aspect of the OS pedis. Relation. — Posteriorly with the perforatus; anteriorly with the radialis accessorius and the radius. Connected with the terminal portion of the tendon, we may remark that the synovial POSTERIOR ANTIBRACHIAL GROUP. 229 capsule of the navicular bone, termed the navicular sheath, forms two ciil-de-mcs, one stretching upwards almost to the inferior cul-de-sac of the sesamoid sheath, the other being situated under the inferior navicular ligament. A broad strengthening sheath of fibrous tissue covers the plantar aponeurosis and blends with it inferiorly, being attached above by two bands to the sides of the first phalanx. Action. — It flexes the joints below the carpus, and assists in flexiugr the latter. FtG. S2. Longitudinal section through the digit of a Horse. 1, The skin ; 2, Extensor pedis tendon ; 3, Synovial cap- sule of pastern joint; i, Metacarpus; 5, Perforatus tendon ; 6 (omitted In cut), Perforans tendon ; 7, Synovial sheath ; 8, Projecting synovial cul-de-sac; 9, Inner aspect of sesamoid bone ; 10, The fetlock ; 11, The Y-ligament ; 12, The V-ligament ; 13, Proximal phalanx ; 14, Terminal portion of extensor tendon; 15, Mesian phalanx; 16, Third sesamoid or navicular bone ; 17, The sensitive frog ; 18, Distal phalanx ; 19, The hoof ; 20, Sensitive laminse. ULNARIS ACCESSORIUS. {Flexor Accessorius Suhlimis.) (Fig. 81. c".) Situated on the posterior part of the fore-arm, between the external and middle flexors of the metacarpus, it is triangular. 230 MYOLOGY. passing obliquely downwards and inwards ; it has a short, thick, fleshy belly, ending in a long, slender, flat tendon. OHgin. — From the posterior border and summit of the ole^ cranon. Insertion. — It blends with, and helps to form the tendon of the perforans near the carpus. Relation. — Superiorly with the fascia ; internally with the flexor metacarpi internus ; externally with the medius. Action. — It assists the flexor perforans. RADIALIS ACCESSORIUS. {Flexor Accessorius Profundus.) (Fig. 81. c'.) A small muscle situated on the postero- inferior part of the- radius. Somewhat radiating, flat, and elongated, passing down- wards and slightly inwards, it ends above the knee in a slender tendon. Origin. — From the posterior part of the shaft of the radius. Insertion. — It joins the tendon of the perforans. Relation. — Anteriorly with the radius ; posteriorly with th& perforatus and perforans. Action. — To assist the flexor perforans. Metacarpal Eegion. Below the carpus we find only two pairs of exceedingly small muscles : — Interossei metacarpei. Lumbricales. INTEROSSEI METACARPEI. (Interossei Palmares, Human.) Situated on the inside of the small metacarpal bones, these muscles each consist of a thin, fleshy belly, and a long, slender tendon, which sometimes joins the band extending from the suspensory ligament to the extensor tendon, or may join the tendon itself. These muscles belong to the rudimentary small metacarpal bones, and hence are themselves rudimentary ; the interosseus of the middle bone is usually considered as being represented by the suspensory ligament GLUTEAL REGION. 231 LUMBRICALES. (^Litmbrici.) These small muscles originate on either side of the perforans, and the sesamoidean ring of the perforatus tendons ; they termi- nate in their tendons, which become lost in the coverings of the fetlock joint. Muscles of the Pelvic Limb. The movements caused by these muscles resemble those of the anterior limb. It should, however, be borne in mind that the stifle joint allows more extensive and varied motion than the elbow, while the motion in the tarsus is less free than that in the carpus, the former being in effect purely ginglymoid ; also that the posterior is capable of more extensive abduction at the hip joint than is the anterior limb at the shoulder, although the former is more bound by ligaments. The muscles of the liinb in question may be divided into those associated with the follow- ing regions : — Gluteal The hip. Femoral The thigh. Tibial '. The leg. Metatarsal The foot. Gluteal Region. The muscles of this region, called also the hip or the croup, arise externally or internally from the pelvis, the sacrum, and the sacro-sciatic ligament, and are all attached to the femur near its proximal end, being related with the hip joint. Collectively the muscles from which this region is named form in the horse an enormous fleshy mass, apparent in the living animal as a rounded prominence, behind and above the anterior iliac spine, to which, and to the sacral spine, the strong gluteal fascia which invests them is firmly attached ; a thin layer of fat is generally found covering the region superiorly. In this region we have one group containing nine muscles, named as follows : — 232 MYOLOGY. Gluteus externus. Gluteus maxim us. Gluteus internus. Rectus parvus. Obturator externus. Obturator internus. Pyriformis. Gemellus anticus. Gemellus posticus. GLUTEUS EXTERNUS. {Ilio-trochanterius Medius.) (Pl. IL 56; Fig. 84. h.) This is a V-shaped muscle situated on the external part of the croup, its fibres converging downwards. It consists of a muscular and an aponeurotic portion ; the former is double, the parts con- verging and ending in a flat tendon ; the aponeurotic joins the fleshy portion posteriorh^ and is hidden under the triceps abduc- tor femoris. Origin. — The anterior portion arises from the anterior spine of the ilium, the pocterior from the second and third sacral spines ; also from the gluteal fascia. Insertion. — To the trochanter minor; the aponeurotic portion reaches the tuberosity of the ischium and the sacro-sciatic liga- ment. Relation. — Externally with the gluteal fascia ; anteriorly with the fascia lata ; posteriorly with the triceps abductor ; internally with the maxim us, Aotion. — It abducts the thigh. GLUTEUS MAXIMUS. {Ilio-trochanterius Magnus.) (Pl. III. 30 ; Fig. 84, c.) This is a very large muscle occupying the iliac dorsum, and stretching forwards over the lumbar region ; it is fleshy and thick in its centre, terminating in t"ft^o tendons. Origin. — From the iliac shaft, crest, dorsum, and spines, anterior and posterior, the side of the sacrum, the sacral and part of the sacro-sciatic ligaments, and the tendinous envelope of the longissimus dorsi as far forward as the last rib. Insertion. — By two tendons, one to the summit of the tro- chanter major, the other anteriorly to the crest below the con- GLUTEAL REGIOJN-. 233 Yexity, over which it passes, with an interposed synovial bursa ; a small fleshy insertion is often found posteriorly. Relation. — Externally with the extemus and the fascia; internally with the internus, sacro-sciatio ligament, and the ilium ; anteriorly with the fascia lata and the longissimus dorsi ; posteriorly with the triceps abductor femoris. The inner and anterior portion which terminates in the anterior tendon has been rather unnecessarily described as a separate muscle; this possible separation is shown in Fig. 83. a. Action. — To extend the femur on the pelvis, and when the posterior limbs are fixed, to assist in rearing. Deep-seated muscles of the gluteal region, a, Deep anterior portion of gluteus maximus ; 6, Gluteus internus ; c. Common tendon of obturator inlemus and pyriformis ; d d, Gemellus anticus and posticus ; e, Ischio- femoralis. GLUTEUS INTERNUS. {Ilio-trochanterms Parvus.) (Fig. 83. 6.) Situated underneath the maximus and above the hip joint, this is a short and fan-shaped muscle, the fibres converging outwards. OHgin. — From the shaft of the ilium, the ischiatic spine, and the capsular ligament of the hip joint. 234 MYOLOGY. InseHion. — By a tendon to a roughened space inside the con- vexity of the trochanter major of the femur. Relation. — Externally with the maximus ; internally with the femur and hip joint. Action. — ^To abduct the thigh, and rotate it inwards. RECTUS PARVUS. (Ilio-femoralis Parvus — Grele.) Situated in front of the hip joint, this is a very small, pale^ and fusiform muscle, with a fleshy belly, and tendinous ex- tremities. Origin. — From the brim of the acetabulum, towards the out- side ; or it may be by two origins, an outer one, and one from between the tendons of origin of the rectus femoris, and the capsular ligament of the hip joint. Insertion. — To the anterior and upper part of the femur, just below the hip joint, by aponeurotic slips. Relation. — Externally and internally with the rectus femoris ; posteriorly with the capsular ligament. Action.-^liO tense the capsular ligament of the hip joint during flexion of the femur. OBTURATOR EXTERNUS. {Suhpuhio-troclianterius- Externus.) Placed on the inferior surface of the os. innominatum, below the obturator foramen, which it covers, this muscle is flat, thick, and triangular, its belly consisting of delicate fasciculi, which pass outwards. Origin. — From the surface of the pubis and ischium, attached to the obturator ligament. Insertion. — In the trochanteric fossa. Relation. — Inferiorly with the pectineus and adductors ; supe- riorly with the capsular ligament of the hip joint and obturator ligament ; posteriorly with the triceps abductor and iscl»*'o- femoralis. Action. — To rotate the femur outwards, and adduct it. GLUTEAL REGION. 235 OBTURATOR INTERNUS. {Suhpubio-troclianteriits Internus.) (Fig. 83. c.) Situated ou the floor of the pelvic cavity, covering the obturator foramen, and corresponding to the extemus; it is fan-shaped, with a delicate, fleshy belly, terminating in a flat tendon. Origin. — From the border of the obturator foramen and its ligament ; it passes through the lesser sciatic notch, behind the acetabulum, where its tendon joins that of the pyriformis. Insertion. — In the trochanteric fossa. Relation. — Superiorly with the pelvic fascia ; inferiorly with the obturator ligament, ischium, and pubis ; outside the pelvis, with the sciatic nerve above, and the externus below. Action. — To rotate the femur outwards, and perhaps to abduct it slightly. PYRIFORMIS. (Sacro-trochanterius. ) (Fig. 83. c.) Situated laterally in the pelvic cavity, this is a flat, elongated, semipenniform muscle, with a small tendon of insertion. Origin. — From the transverse processes of the sacral vertebrae, and the inner surface of the iliac shaft ; lying along the inner side of the sacro- sciatic ligament, it passes through the lesser sciatic notch to join the tendon of the obturator internus. Insertion. — In the trochanteric fossa. Relation. — With the pelvic • fascia internally ; externally with the OS innominatum ; outside the pelvis it is crossed by the sciatic nerves ; the obturator vessels and nerves pass along its lower border. Action. — To rotate the femur outwards. GEMELLUS ANTICUS AND POSTICUS. (Gemini — Ischio-trochanterii.) (Fig. 83. d d.) A pair of very delicate muscles, variable in form, and usually situated one above and before, the other below and behind the obturator internus tendon, with fleshy bellies and tendinous insertions. 236 MYOLOGY. Origin. — From the shaft of the ischium ou either side of the conjoined tendon of the pyriformis and obturator internus, their fibres blending with it and passing outwards. There may be another flat and somewhat large muscle sitftated between the above and the obturator externus, originating also from the ischial ramus. Insertion. — In the trochanteric fossa. Relation. — Posteriorly with the sciatic nerves ; anteriorly with the capsular ligament of the hip joint, and the obturator externus. Action. — Like the preceding, to rotate the femur outwards. Femoral Region. The muscles of this regiou cover more or less the shaft of the femur, some of them reaching as far as, or below the stifle joint ; the majority of them have a pelvic origin.- These muscles may be conveniently divided into the four following groups : — Internal. I Anterior. External. I Posterior. Internal Femoral Group. adductors. These form the large fleshy mass situated between the inferior pelvic surface and the stifle joint ; they are six in number : — Sartorius. Gracilis. Pectiueus. Adductor brevis. ^ Adductor longus. r Triceps adductor feraoris. Adductor maguus. J SARTORIUS. (Sublujnbo-tibialis.) (Fig. 77. I.) Situated in the abdominal cavity at the pelvic inlet, and along the inner aspect of the thigh, it is long, thin, fleshy, and pyra- midal, extending obliquely downwards, forwards, and outwards. INTERNAL FEMORAL GROUP. 237 Origin. — From the brim of the pelvis, and from the iliac fascia, near the tendon of the psoas pan^us. Insertion. — lu common with the gracilis, by fascia to the internal straight ligament of the patella. Relation. — Anteriorly with the crural arch and fascia ; inter- nally with the psoas magnus and iliacus; posteriorly with the gracilis, pectiueus, and vastus intemus. Its posterior border is related with the femoral artery, which, with the vein and internal saphenic nerre, passes through a space included between this muscle, the iliacus, and the pectineus, termed the femoral space. Action. — To adduct and flex the femur. GRACILIS. (Sicbpubio-tiblalis.) (Fici. 77, c.) Situated on the internal part of the thigh, this is a broad, thin, quadrilateral muscle, directed downwards and outwards. It has a flat fleshy belly, terminating in a broad aponeurosis. OrifjirL — From the inferior surface of the ischio-pubic sym- physis, where it meets its fellow. InseHion. — With the sartorius, to the internal straight liga- ment of the patella, and also to the supero-internal part of the tibia ; posteriorly its fascia blends with that of the biceps rotator tibialis, the two forming the fascia of the region. Relation. — Anteriorly with the sartorius; internally with the adductor muscles of the thigh ; posteriorly with the biceps rotator tibialis ; externally with the crural aponeurosis and saphenic vein. Actiom. — To adduct the limb, and tense the fascia of the les. PECTINEUS. {Super-puhio-femoralis. ) (Fia. 76./.) Situated on the inner side of the preceding, this muscle is conical, the' fibres extending outwards and backwards. It is tendinous, with a fleshy belly, bifid superiorly for the passage of the pubio-femoral ligament. 238 MYOLOGY. Origin. — From the brim and inferior surface of the pubis ; it is also attached to the pubio-femoral ligament, which passes through its tendons of origin. Insertion. — To a roughened surface' on the inner side of the femur, below the internal trochanter, and near the nutrient fora- men. Relation. — Anteriorly with the sartorius, part of the psoas magnus, iliacus, and vastus internus ; posteriorly with the adductor brevis and gracilis ; superiorly with the obturator extemus. The femoral vessels cross it. Action. — To adduct and flex the thigh, and to rotate it in- wards. TRICEPS ADDUCTOR FEMORIS. This name has been applied to a group of three muscles, situ- ated on the inner surface of the thigh, and covered by the gracilis, which act the part of adductors. They have also been described as consisting of a biceps and a single muscle ; we describe them as three distinct muscles, and name them, from before backwards, the brevis, the longus, and the magnus. ADDUCTOR BREVIS. (Subpubio-jemoralis.) (Fig. 76. g.) Situated on the .inner aspect of the thigh, behind the pec- tineus, this muscle is pyramidal, with the base upwards, its fibres converging downwards and outwards. Fleshy, with tendinous insertions inferiorly, it is often somewhat blended with the longus. Origin. — Superiorly from the inferior surface of the pubis. Insertion. — To a square, roughened surface on the posterior part of the shaft of the femur, about the middle, together with a portion of the long adductor. Relation. — Anteriorly with the pectineus ; posteriorly^ with the longus ; externally with the gracilis ; internally with the obturator extemus. • Action. — To flex, adduct, and rotate the femur outwards. EXTEBNAL FEMORAL REGION. 239 ADDUCTOR LONGDS. [Subpuhio-femoralis Posterior.) (Fig. 76. h.) Situated on the inner aspect of the thigh, covered by the -gracilis, this muscle is long, flat, and prismatic, extending outwards and downwards. Origin. — From the inferior surface of the posterior part of the pubis. Insertion. — By two divisions, one attached by the insertion of the brevis, the other, with the magnus, above the internal condyle of the femur at the attachment of the lateral ligament. Relation. — Anteriorly with the brevis and obturator externus ; posteriorly with the magnus ; externally with the gracilis ; inter- nally with the ischio-femoralis and sciatic nerves. The femoral vessels pass between its two divisions. Action. — To adduct the femur, and rotate it outwards. ADDUCTOR MAGNUS. {Semimembranosus — Ischio-tibialis.) (Fig. 76. i.) Placed behind the preceding, on the postero-internal part of the thigh, this muscle is thin at its extremities and posterior border, thick and fleshy elsewhere, terminating in a short tendon. Origin. — Chiefly from the inferior surface and tuberosity of the ischium by tendinous fibres, and by a slender band from the coccygeal fascia. Insertion. — To a small roughened surface on the inner side of the internal condyle of the femur Relation. — Anteriorly with the longus, to which it is very adherent ; externally wi ua the gracilis ; posteriorly with the biceps rotator tibialis ; internally with the triceps abductor. Action. — To adduct and extend the thigh. If the limb be iixed, it assists in raising the anterior parts of the trunk in ^'rearing." External Femoral Region. abductors. This region contains only one muscle, which is situated laterally with respect to the haunch, but more posteriorly with regard to the femur. 240 MYOLOGY. TRICEPS ABDUCTOR FEMORIS. {Ischio-tibialis Fxtermis.) (Pl. II. 55; Fig. 84. d d d.) Situated on the external part of the haunch, behind and below the great gluteal muscles, this is a very large and fleshy muscle. Via. 84. Muscles 0* the thigh and haunch— left side ; the external fascia being removed, o, Tensor fasciae latse ; 6, Gluteus externus ; c, Gluteus maximus ', d d d. Triceps abductor femorls ; e e. Biceps rotator tibialis ; /, Part of adductor magnus. made up of two prismatic portions, with two origins and three insertions. The anterior portion is much the longer. The fibres pass downwards in a somewhat curved manner, the larger con- vexity being to the rear. ANTERIOR FEMORAL REGION. 241 Origin. — The anterior portion arises from the spine of the sacrum, the coccygeal fascia, and the sacro-sciatic ligament ; also from the ischial tuberosity ; the posterior portion is attached to the crest of the ischial tuberosity. Insertion. — Anteriorly to the external side of the patella and its external ligament, a synovial bursa lying between it and the bone ; posteriorly by a strong aponeurosis to the tibial fascia, which it helps to form, and by it to the tibial crest. It sends a strong slip which is attached near the insertion of the ischio- femoralis. Relation. — Externally and superiorly with the gluteal fascia^ to which it adheres above ; internally with the fascia of the gluteus externus, which separates it from the maximus and th6 femoral trochanter ; with the sciatic nerves, the adductor muscles^ and biceps rotator, excepting at the upper portion, where it is. related posteriorly with the latter muscle. Action. — The anterior portion extends the femur and abducts, the limb ; the posterior portion flexes the stifle joint and tenses the tibial fascia. It assists the abductor magnus when the limb is fixed. (Vide Abductor Magnus.) Anterior Femoral Region. The muscles of this region lie in the space between the iliac spine above, the patella below, and the femur and hip joint posteriorly. They are as follows : — Tensor fasciae latse. Rectus femoris. \ Vastus externus. f _, . , . ,. tT . • . r Tnceps or quadriceps cruralis. V astus intemus. i Crureus. ^ TENSOR FASCL^ LAT^. {Tensor Vagince Femoris — Ilio-aponeuroticus.) (Pl. n. 54 ; Fig. 84. a.) . Situated in front of the gluteus externus, and on the outside of the vastus externus, this muscle is flat and triangular, radiat- ing downwards and backwards. Attachments. — The fleshy portion arises from the anterior iliac 242 MYOLOGr. spine, and from It springs the aponeurotic expansion termed the fascia lata. (See Fasciae of the Posterior Limb, p. 255.) Relation. — Internally with the iliacua, rectus femoris, and vastus .externus ; externally with the skin ; posteriorly with the gluteus maximus and externus; anteriorly with the precrural lymphatic glands. Action. — It assists in flexing the femur, raising the limb ; and it tenses the fascia lata. . CRURAL MUSCLES. The remaining muscles of this region, being all of them inserted to the patella, may be described as a single muscle, the triceps or quadriceps cruralis ; or the rectus may be regarded as a single muscle, and the other three described together as the triceps cruralis ; or, again, they may be considered as separate muscles. The above names being borne in mind, the last is perhaps the simplest method, and is the one adopted here. These muscles are considerably blended, and cannot well be perfectly separated without cutting muscular fibre. RECTUS FEMORIS. {Ilio-rotvlejis.) (Pl. IIL 34j Fig. 76. Z.) Situated on the anterior part of the thigh, between the two vasti, it is thick, elongated, and fusiform, consisting of two short, flat tendons of origin, and a fleshy intersected belly, terminating in a conical aponeurotic envelope. It is directed downwards and forwards. Origin. — From two depressions, one on each side of the iliac shaft, just before the acetabulum. Insertion. — To the upper part of the patella. Relation. — It lies between the vasti, and above the crureus, and superiorly between the iliacus and the tensor fasciae latse, with which it is related anteriorly. A pad of fat occupies the space between its tendons of origin and the capsular ligament of the hip joint. Action. — To flex the femur, and extend the leg. ANTERIOR FEMOEAL REGION. 24$ VASTUS EXTERNUS. {Femoro-rotuleus Exterwus.) (PL. III. 35.) Situated on the outer side of the rectus femoris, this muscle is broad, thick, flattened laterally, and semi-ovoid, extending downwards and forward^s; it is fleshy, with strong tendinous intersections. Origin. — From the external and part of the anterior aspects of the shaft of the femur, and from the base of the trochanter major downwards. Insertion. — To the upper and outer part of the patella; or it may join the rectus femoris. Relation. — Externally with the tensor fasciae latse, and gluteus I'xternus ; internally with the rectus, crureus, and vastus intemus,. with which inferiorly it is intimately blended ; posteriorly with the triceps abductor femoris and the femur. Action. — To extend the leg. VASTUS INTERNUS. (Femoro-rotuleus Intemus.) (Fig. 76. k.) Corresponding to the externus, this muscle is situated on the inner side of the rectus femoris, the two forming a channel in which are lodged the rectus and crureus. It is semi-ovoid, and fleshy, becoming tendinous at its insertion. Origin. — From the neck of the femur, its antero-internal surface, and the trochanter internus. Insertion. — To the upper and inner side of the patella. Relation. — Externally with the rectus ; internally with the sartorius, pectineus, psoas magnus, iliacus, adductor magnus, and crural fascia. Action. — To extend the leg. CRUREUS. (Femoro-rotuleus Medius.) Situated below the rectus, and between the two vasti, this muscle is small, cylindrical, fleshy, and tendinous at its extremi- ties ; it is separated from the vasti with difficulty. .244 MYOLOGY. Origin. — From about the lower third of the anterior surface of the femur. Insertion. — To the upper surface of the patella, and the capsular ligament of the joint. Relation. — Anteriorly with the rectus; posteriorly with the femur ; laterally with the vasti. Action. — To assist the vasti, and tense the capsular ligament. Posterior Femoral Region. This region contains two muscles, a large superficial one, and a small one deeply situated ; they are as follows : — Biceps rotator tibialis. Iscbio-fem oralis. BICEPS ROTATOR TIBIALIS. {Semitendinosus — Ischio-tibialis Posticus. ) (Pl. II. 61 ; Fig. 84. e. e.) Situated behind the triceps abductor, and curved like it, with the convexity behind, this muscle is long, cylindrical, and bifid above, consisting of pale, fleshy fibres, divided by a strong aponeurosis. Origin. — By one head, from the spine of the sacrum, and the sacro-sciatic ligament, in common with the triceps abductor; the other, which is considerably shorter, comes from the ischial .tuberosity. Insertion. — To the supero-internal part and anterior crest of the tibia, its aponeurosis blending with the tibial fascia and the periosteum. Relation. — Superiorly and posteriorly it is covered by the gluteal ' fascia, and its sacral portion partly covers the triceps abductor, being related with it and the sciatic nerves anteriorly ; externally with the abductor magnus. Action. — To extend the femur, flex and rotate the leg out- swards, and tense the tibial fascia. ISCHIO-FEMORALIS. {Quadraius Femoris.) (Fig. 83. e.) Situated behind the femur, between the adductor and abductor muscles. This muscle consists of a flattened band, running down- awards and outwards. ANTERIOR TIBIAL GROUP. 245 Origin. — From the inferior surface of the ischium, in front of the tuberosity. Insertion. — To a linear imprint on the posterior surface of the femur, just below the level of the trochanter intemus. Relation. — Anteriorly with the femur and obturator externus ; posteriorly and externally with the adductor magnus ; internally with the gemellus posticus, and the sciatic nerves. Action. — To extend and adduct the femur, but not, in the horse, to rotate it. Tibial Region. This region corresponds to the antibrachial region of the anterior limb, and, like the latter, contains chiefly flexor and extensor muscles. The strong tibial fascia invests the region, and is attached to the tibial crest, and to the summit of the calcaneum, being tensed by the gracilis and other muscles. The muscles of this region cover the tibia and fibula, except on the inner side of the former, and they consist of an anterior and a posterior group ; but as the flexor side of the tarsal joint is anterior, and, in the joints below, posterior, we find flexor and extensor muscles both before and behind. In the anterior limb it is not so, the carpus and the joints beloAV all flexing in the same direction. Anterior Tibial Group. We subdivide this group into the flexors and extensors; there are two of the latter and only one of the former. Flexor. Extensors. Flexor metatarsi. I Extensor pedis. I Peroneus. FLEXOR METATARSL (Tibio-premetatarseus.) (Fig. 85. a.) This muscle is situated on the antero-external aspect of the leg, and consists of two distinct parts, one fleshy, the other tendinous. The tendinous portion appears as a very strong fibrous cord, situ- ated in front of the fleshy portion, and running the whole length of the muscle. The fleshy portion is coniform, thick above, and thinner below. 246 MYOLOGY. Fig. 85. Anterior tibial group of muscles of the right limb, seen from before and the out- side, a. Flexor metatarsi ; a', Tendon to the cuboid ; and a". Tendon to the meta- tarsus, from its funicular portion ; a'". Tendon of its fleshy portion, sending a straight slip to the metatarsus, and an oblique one to the cuneiform bone ; b. Ex- tensor pedis ; V, Its tendon; c, Peroneus: c', Point where its tendon joins that of the extensor pedis ; d. Extensor pedis brevis ; e, Superior, and /, Inferior thick portions of the annular ligament. Attachments. —T The tendinous- portion arises from the depression between the trochlea and condyle of the femur, and lies in the superior tibial groove, clothed above by a reflection of one of the synovial membranes of the stifle joint ; below this point it gives attachment to fibres of the fleshy portion and of the extensor pedis ; in front of the astragalus it forms a ring, through which the tendon of the fleshy por- tion passes ; at the tarsus it bifur- cates, a very strong slip being at- tached to the large metatarsal bone, and a small one, which inclines out- wards, to the cuboid bone. The fleshy portion arises from- the head of the tibia, and its groove, also from the tendinous part, receiv- ing slips from the latter; its tendon of insertion, after passing through, the above-named ring, bifurcates, and is inserted by a broad portion to the front of the great metatarsal bone, and by a smaller slip, which winds inwards, to the small cunei- form bone. Relation. — Anteriorly with the extensor pedis; posteriorly with the external aspect of the tibia, and the anterior tibial artery. Action. — It flexesthe tarsal joint. The tendinous portion may be re- garded as a strong fibrous com- munication between the femur and the metatarsus, which, when the stifle joint is flexed, becomes tensed, and mechanically repeats the action, upon the joint below. ANTERIOR TIBIAL GROUP. 247 EXTENSOR PEDIS. {Femoro-pi'ephalcmgeus.) (Fig. 85. I.) Situated on the anterior surface of tlae tibia and bones below this is a long^ fusiform muscle, extending downwards and back- wards. A little above the tarsus, the belly terminates in a long, flat tendon, which, bound down by the three bands of the annular ligament, passes down the front of the tarsus and metatarsus, near the middle of which it receives the extensor brevis and the tendon of the peroneus ; the united tendon now passes down, and is arranged like that of the anterior limb. Origin. — From the fossa between the trochlea and external condyle of the femur, by the tendon of the flexor metatarsi, common to it. Insertion. — To the capsular ligament of the fetlock joint, the anterior surface of the two first phalanges, and the pyramidal process of the os pedis. Relation. — Anteriorly with the fascia; internally with the flexor metatarsi ; posteriorly with the peroneus. Action. — To extend the entire digit, and flex the tarsal joint. p-ERONEUS. {Peroneo-prephalangeus. ) (Fig. 85. c.) Situated on the external side of the leg, this is a long and somewhat penniform muscle, consisting of a prismatic, fleshy belly, which originates by a short, and terminates by a long tendon ; the latter passes through a theca on the external side of the tarsus, joining the tendon of the extensor pedis below the joint. Origin. — From the external lateral ligament of the stifle joint, and the entire length of the fibula. Insertion. — It joins the tendon of the extensor pedis. Relation. — Externally with the fascia; anteriorly with the extensor pedis ; posteriorly with the flexor pedis perforans. Action. — It assists the extensor pedis. 248 MYOLOGY. Posterior Tibial Group. For convenience of description, we subdivide the muscles of this group, but the subdivision is a somewhat artiJ&cial one, as some of the muscles have two actions, flexing one joint and extending another. Extensors. Gastrocnemius. Plantaris. Flexors. Flexor pedis perforatus. Plexor pedis perforans. Flexor pedis accessorius. Popliteus. GASTROCNEMIUS. (Bifevi ero-crjcaneus, ) (PL. III. 38.) Situated at the back of the leg, this muscle is somewhat heart- shaped, ending in a flattened tendon ; the fleshy belly is divisible into two portions, and intersected superiorly by strong tendons. Origin. — By two heads ; one from a ridge extending upwards from the external condyle in front of the supracondyloid fossa ; the other from the posterior surface of the femur, just above the intercondyloid fossa, and from the internal condyle. Insertion. — To the posterior part of the summit of the calcaneum, a synovial bursa being interposed between it and the anterior part, over which it passes. Relation. — Anteriorly with the flexor perforatus, popliteus, popliteal vessels and nerves, and the vastus externus above ; posteriorly with the triceps abductor femoris ; internally with biceps rotator tibialis ; superficially with the tibial fascia ; inferiorly the tendon is covered by that of the flsxor perforatus, the two forming the Tendo-AcMllis. Action. — To extend the tarsal joint. POSTERIOE TIBIAL GROUP. 249 PLANTARIS. {Soleus — Peroneo-calcaneus.) (Pii. III. 39.) Situated on the postero-external part of the leg, to the out- side of the gastrocnemius, this muscle is, in the horse, slender find rudimentary, with a small, delicate tendon of insertion. Origin. — From the external part of the head of the fibula. Insertion. — Together with the tendon of the gastrocnemius to the point of the calcaneum. Relation. — Externally with the fascia ; internally with the gastrocnemius. Action. — It assists very slightly the gastrocnemius. FLEXOR PEDIS PEKFORATUS.* {Femoro-phalangeus. ) (Fig. 86 6.) Situated immediately underneath the gastrocnemius, this muscle is in shape funicular, consisting of a strong fibrous cord, with a slightly fleshy portion above, and arising from the supra- <3ondyloid fossa ; the belly is succeeded by a strong tendon, united to fascia, which is fixed to the inner surface and ridge of the tibia and the summit of the calcaneum, being continuous with the tibial fascia, and enclosing the entire tendo-Achillis. The tendon, at first under that of the gastrocnemius, winds round its inner side, and then surmounts it;. on reaching the point of the calcaneum it forms a cap, giving slips of insertion to the sides of that bone ; a large synovial bursa exists here, which is one of the seats of the lesion termed capped hock. It now descends posteriorly, and is disposed as is the corresponding tendon in the anterior extremity, forming a synovial sheath and ring for the perforans tendon, and finally bifurcating to become attached to the sides of the os coronse. Relation. — Posteriorly with the gastrocnemius ; anteriorly with the tibia, the popliteus, perforans, and accessorius muscles. * This muscle was formerly described under the name of gastrocnemius intemus. The more appropriate one now in use is adopted here. 250 MYOLOGY. Action. — To flex the fetlock and pastern joints, and assist iit extending the tarsus ; when the animal is stationary, it serves mechanically, a* a fibrous band, to prevent flexion of the tarsal joint. FLEXOR Pm)IS PERFOBANS. ( Tibio-phalangeua. ) (Fig. 86. c.) Situated on the posterior aspect of the leg, extending from the head of the tibia to the distal phalanx, this muscle is thick and prismatic, consist- ing of a fleshy, intersected belly and long tendon of insertion. The belly is partially bifid, the internal portion being the larger. The tendon com- mences a little above the hock, passes through the groove on the inner side of the calcaneum, first crossing the posterior capsular ligament of the tarsus, where it is bound down by fibrous tissue, in a synovial sheath, the usual seat of Thorough-pin. It then descends behind the metatarsal bone ; about half-way down, it is joined by the check ligament, which springs from the lower bones of the tarsus and head of the metatarsal bone, and is similar to, but considerably less than, that of the fore extremity. It is joined above by the tendon of the flexor accessorius, and is otherwise disposed exactly as the perforans tendon of the anterior extremity. Origin. — From the roughened pos- terior aspect, and head of the tibia, the fibula, and fibulo-tibial ligament. Insertion. — To the semilunar ridge on the solar surface of the os pedis. FiQ. 86. Posterior tibial group of muscles of the right limb— postero-internal view. The gastrocnemius is removed. a, Popliteus; 6, Flexor pedio per- foratus; t'. Its tendon; 6", Expansion of its tendon forming the cap of the hock; c, Flexor pedis perforans; c', Its tendon ; d, Floxor accessorius, d', Union of its tendon with that of the perforans. POSTERIOR TIBIAL GROUP. 251 Belation. — Posteriorly with the gastrocnemius and flexor perforatus ; anteriorly with the tibia ; internally with the flexor pedis accessorius ; externally with the peroneus. Action. — To flex the phalanges, and assist in extending the tarsal joint. FLEXOR PEDIS ACCESSORIUS. {Flexor Obliguus — Peroneo-phalangeus.) (Fig. 86. d.) This muscle is situated on the posterior part of the leg, between the popliteus and flexor pedis perforans. It is fleshy, with numerous fibrous intersections, and inferiorly a terminal tendon. Origin. — From the external tuberosity of the tibia, and some- times slightly from the fibula; the tendon commences just above the tarsal joint, and passes through a theca on its internal aspect. Insertion. — It joins the tendon of the flexor perforans at about a third from its commencement. Relation. — Posteriorly with the gastrocnemius and flexor perforatus ; anteriorly with the perforans, the popliteus, and the posterior tibial artery. Action. — To assist the flexor pedis perforans. POPLITEUS. (Femoro-tibialis Obliquus.) (Fig. 86. a.) Situated at the back of the tibia, just below the stifle joint, this muscle is triangular and fleshy, the fibres passing obliquely downwards and inwards. Origin. — By a tendon from a fossa outside the external con- dyle of the femur ; it is attached to the capsular ligament of the stifle joint. Insertion. — The triangular surface on the supero-posterior part of the tibia, and the upper portion of its internal border. Belation. — Posteriorly with the gastrocnemius and flexor perforatus ; anteriorly with the tibia, the capsular ligament, and the tibial vessels ; externally with the flexor pedis perforans and accessorius; internally with the biceps rotator, and tibial fascia. Action. — It flexes the leg, rotates it inwards, and tenses the capsular ligament of the stifle joint. 252 MYOLOGY. Metatarsal Region. In this region we have the lumbricales and interossei as in the anterior extremity, and also the extensor pedis brevis. EXTENSOR PEDIS BREVIS. (Extensor Pedis Accessorius.) (Fig. 85. d) Situated in front of, and below the tarsal joint, it is small and triangular in form, filling up the space between the converging tendons of the extensor pedis and peroneus. Origin. — From the infero-anterior part of the astragalus ; it is also attached to the cuneiform bones. Insertion. — It joins the tendons of the extensor pedis and peroneus. Relation. — Underneath this muscle passes the anterior tibial artery, giving oflf the perforating pedal branch. Action. — It assists slightly the extensors of the foot. Arrangement of the Fascia. We have already seen that the muscular system is invested by an areblo-fibrous covering, which has been named the superficial fascia. This covering varies very much in density in different regions, and in some becomes blended with the aponeurosis of the panniculus ; and generally where the muscles are braced by the fleshy portion of the latter, the investing faecia is more or less rudimentary, as in the head and neck ; it is with difficulty demonstrable as a separate structure in the latter. The -tunica abdominalis has been considered as an elastic development of the investing abdominal fascia. DEEP FASCLE. The following may convey a general idea of the arrangement of the deep or aponeurotic fasciae. Each muscle is more or less completely covered by a fold of fascia, which forms a sheath round it and its tendon ; it then passes to and covers another ARRANGEMENT OF THE FASCIA. 25 S muscle, and so on until it finally gives oflf an expansion which covers the entire group or region, becoming firmly attached to the skeleton, and usually at its salient points. Hence we may regard an aponeurotic fascia as a compound sheath, which con- tains in its compartments muscles and their concomitant struc- tures, and aids the former in their action by passive support ; the support thus afforded is not always wholly passive, since, as we have seen, some fasciae are regulated as to their tension by special muscles, the fasciae of the limbs affording good examples of this arrangement. Some of the deep fasciae merit special attention, and we shall consider them in the order generally observed in dealing with other widely-diffused structures — i.e., as apertaining to the Head, the Trunk, and the Limbs. FASCLE OF THE HEAD. In this region there is little that is noteworthy in the disposi- tion of the fascia. It is, however, much stronger in the posterior than in the anterior portion, the muscles of the former being separated merely by folds which closely resemble ordinary con- nective tissue. The temporal fascia is the name given to a strong fold which covers the temporal fossa, being attached to the parietal ridge and to the zygoma, and corresponding to the temporalis and attollentes muscles. FASCIA OF THE TRUNK. These are the cervical, dorso-lumbar, abdominal, and thoracic fasciae. The deep fascia of the cervical region is better marked than the superficial, and it invests the muscles in the typical manner above described, becoming attached to the vertebrae. In the dorso-lumbar region it is variable, being thin in some situations, but thick and strong in others ; that covering the postero- superior part of the longissimus dorsi is actually tendinous in structure, giving origin to part of the gluteus maximus. The dorso-lumbar fascia becomes continuous posteriorly with that of the gluteal region, and anteriorly with that of the external scapular region. The deep abdominal fascia chiefly includes the following 254 MYOLOGY. portions : — The transverse, the iliac, the pelvic, the inguinal, and the perineal. The transverse (fascia transversalis) is inter- posed between the transversalis abdominis and the peritoneum, and is in the horse a very thin structure ; in the human subject, and in some other animals, it is thickened posteriorly, and attached to the crural arch. The iliac fascia (fascia iliaca) covers the muscles of the sublumbar region, especially the psoas magnus and iliacus, which it enfolds and accompanies to their insertion. It is attached internally along the tendon of the psoas parvus muscle, by which it is tensed, externally to the anterior iliac spine ; anteriorly it becomes very rudimentary, although it may sometimes be traced as far as the arcuate ligament of the diaphragm. The sartorius and cremaster muscles arise partly from this fascia. The pelvic fascia (fascia pelvica) is a strong layer lining the pelvic cavity, and covered anteriorly by the peritoneum ; inferiorly, it splits into two folds, the external of which lines the sides and floor of the cavity, and is named the obturator fascia, since it covers the internal muscles of that name ; it also furnishes a sheath for the internal pudic vessels. The other fold, the recto- vesical fascia, is reflected inwards and posteriorly gives ofif bands, ene of which separates the bladder from the rectum, another investing the latter, while two others serve as ligaments of the bladder. The inguinal and perineal fasciae will be more appro- priately described in a future section of the work. The thoracic fascia stretches across the anterior opening of the thurax, and is its anterior boundary, surrounding and bracing the v.'uious structures which pass through, and helping to keep them in their relative positions. FASCIA OF THE ANTERIOR LIMB, These correspond to the various regions of the limb. The external scapvlar fascia is very strong superiorly, and it covers the external scapular muscles, giving otf folds which enclose them. It is attached to the cartilage and spine of the scapula, and is continuous with the dorso-lumbar fascia behind, the subscapular fascia round the edge of the antea-spinatus^ and below with the brachial fascia. It is tensed by the pectoralis parvus and teres exteinus muscles. The brachial fascia is comparatively thin ; it covers and invests the humeral and triceps extensor muscles. ARRANGEMENT OF THE FASCIA. 255 ^nd is continued below by the antibrachial fascia, which is exceedingly thick and strong, firmly bracing the muscles of the fore-arm ; it is attached to the inner side of the radius, to its distal end both externally and internally, and likewise to the olecranon. On the inner aspect of the limb it is separable into layers, the external of which is tensed by the pectoralis transversus, while the internal gives off folds which pass between the muscles and form sheaths for them, and is attached supe- riorly to the flexor brachii and scapulo-ulnaris muscles, which are its tensors. Inferiorly, this fascia becomes continuous with the annular ligaments of the carpus, thus helping to form sheaths for the passage of the tendons. FASCIA OF THE POSTERIOR LIMB. The gluteal fascia covers the region of the same name, and is thick, strong, and somewhat elastic, usually containing more or less fatty matter. It is continuous anteriorly with the fascia of the dorso-lumbar region, posteriorly and externally with the crural fascia, and is firmly attached to the anterior iliac and the sacral spines. Its internal surface gives attachment to portions of the gluteus maximus and externus. The femoral or crural fascia surrounds the muscles of the thigh. The anterior and external portions are known as the fascia lata ; the internal portion anteriorly is derived from the aponeurosis of the obliquus abdominis externus; passing backwards, it becomes rudimentary, and is replaced posteriorly by connective tissue. The fascia lata encloses the triceps cruralis, and exter- nally divides into two folds, internal and external ; the former passes between the vastus externus and triceps abductor, and accompanies the tendon of the gluteus externus to its insertion at the trochanter minor ; the external fold covers the triceps abduc- tor muscle, becoming continuous above with the gluteal fascia. The fascia lata is attached inferiorly to the patella, and below is continuous with the aponeurotic insertion of the triceps abductor, and so with the tibial fascia ; it is tensed by its own muscle, the tensor fasciae latse. The tibial fascia, like the antibrachial, to which it corresponds, is very strong and thick, and covers the tibial group of muscles, sending in folds to form sheaths for them. It gives attachment to the triceps abductor, biceps, rotator, and gracilis muscles, which 256 MYOLOGY. presumably act as its tensors. It is attached to the crest and inner aspect of the tibia, and also to the calcaneum, and it biends^ with the annular ligaments of the tarsal joint, assisting in form- ing sheaths for the tendons. This fascia is continued over the tarsus and metatarsus: becoming somewhat thinner inferiorly; between the tendo-Achillis and the flexor muscles of the foot it is very strong, giving powerful bands to the former, and, near the calcaneum, helping to form a sheath for the gastrocmius tendon. Below and before the tendo-Achillis it divides into two folds, which assist externally and internally in the formation of the tarsal sheath, for the perforans tendon ; between these folds are the posterior vessels and nerves of the region. TABLE OF MUSCULAR ATTACHMENTS. In the following Table we enumerate the principal bones of the horse, tabulating the names of the most important muscles which are attached to each :- THE HEAD. Cranial Bones, occipital. Levator humeri. Splenius. Compli&xus, major and minor. Rectus capitis anticus, major, minor, and lateralis. Rectus capitis posticus, major and minor. Obliquus capitis anticus. Stylo-hyoideus. Stylo-maxillaris. Digastricus. PARIETAL. Temporalis. FRONTAL. Levator labii superioris alseque nasi. TEMPORAL. Trachelo-mastoide us. Levator humeri Temporalis. Mastoido-auricularis. SPHENOID. Rectus capitis anticus, major and minor. Pterygoideus, extemus and in- ternus. Facial Bones, superior maxilla Panniculus carnosus. Masseter. Buccinator. Nasal is longus. Dilatator naris lateralis. PREMAXILLA. Dilatator naris inferioris. Depressor labii superioris. MUSCULAH ATTACHMENTS. 257 NASAL. Dilatator naris sucerioris. LACHRYMAL. Orbicularis palpebrarum. Lachrymal is. MALAR. Nasalis longus. PALATINE. Pterygoideus internus. INFERIOR MAXILLA. Masseter. Temporalis. Pterygoideus, externus and interixus. Sterno-maxillaris. Stylo-maxillaris. Buccinator. Levator labii inferioris. Depressor labii inferioris. Mylo-hyoideus. Genio-hyoideus. Digastricus. / HYOID SERIES. Sterno-thyro-hyoideus. Subscapulo-hyoideus. Myo-hyoideus. Genio-hyoideus. Hyoideus magnus. Hyoideus parvus. Hyoideus transvei-sus. Stylo-hyoideus. Certain muscles of the tongue^ pharynx, larynx, and soft palate are not enumerated here. XHii: TRUNK. Cervical Vertebs^c. ATLAS. Levator humeri. Splenius. Trachelo-mastoideus. Obliquus capitis, anticxis and posticus. Rectus capitis ahticus, major, minor, and lateralis^ Longus colli. DENTATA. Longus colli. Levator humeri. Intertransversalis collL Obliquus capitis posticus. Complexus minor. Rectus capitis posticus major. Spinalis colli. SEGMENTS 3 TO 7. Longus colli. Rectus capitis anticus major (3rd to 5th). Intertransversalis colli. Transversalis costarum (7 th) Levator humeri (3rd and 4th). Splenius (3rd to 5th). Serratus magnus. Spinalis colli. Trachelo-mastoideus. Compl'^xus major. Longissimus dorsi (4th to 7th). DORSAL VERTEBRA. Splenius ) Complexus major ) v ^^ /* Trachelo-mastoideus (first 2). Trapezius dorsalis (3rd to 11th). Latissimus dorsi (last 15). Superficialis costarum (last 17). Rhomboideus brevis (2nd to 7th), Longissimus dorsi. S 258 MYOLOGY. fSemispinalis dorsi. Levatores costarum. Longus colli. Psoas parvus (last 3). Psoas magnus (last 2). LUMBAR VERTEBRA. Xiatissimus dorsi. Superficialis costarura (first 3). Longissimus dorsi. Seniispinalis lumborum. Psoas magnus. Psoas parvus. Quadratus lumborum. Intertransversalis lumborum. Transversalis abdominis. Crura diaphragmatica. SACRUM. Longissimus dorsi. Seraispinalis lumborum. Gluteus externus. Gluteus maximus. Triceps abductor feraoris. Biceps rotator tibialis. Pyriformis. .All the coccygeal muscles. COCCYX, j^ll the coccygeal muscles. The Compressor coccygis to th( .first 2 segments. RIBS AND COSTAL CARTILAGES. Scalenus (1st). Superficialis costarum (last 14). Longissimus dorsi (last 16). Transversalis costarum. Serratus magnus (first 8). Lateralis sterni (1st). Triangularis sterni (2nd to 8th). lutercostales. Levatores costarum. Obliquus abdominis externus (last 14). Transversalis abdominis (last 10). Obliquus abdominis \ internus. ^ (cartilages). Pv,ectus abdominis. / Diaphragm (last 12). Psoas magnus (last 2). Quadratiis lumborum (last 3). STERNUM. Panniculus carnosus. Sterno-maxillaris. Sterno-thyro-hyoideus, The four Pectorales. Lateralis sterni. Triangularis sterni. Rectus abdominis. Transversalis abdominis. Diaphragm. Ti-apezius. Levator humeri. Antea-spinatus. Postea-spinatus. Postea-spiuatus minor. Teres externus. Rhomboideus, longus and brevis Serratus magnus. ^ubscapularis. PECTORAL LIMB. Pectoralis parvus. Scapulo-ulnaris. Caput magnum. Scapulo-humeralis posticus. Teres internus. Coraco-humeralis. Flexor brachii. HUMERUS. Antea-spinatus. Postea-spinatus. MUSCULAR ATTACHMENTS. 25» Postea-spinatus minor. Subscapularis. Scapulo-humeralis posticus, Pectoralis, magnus and anticus. Panniculus carnosus. Teres, externus and intern us. Coraco-humeralis. Humeralis obliquus. Caput medium and parvum. Anconeus. Latissimus dorsi. Levator humeri. Extensor metacarpi magnus. Extensor pedis. Three Flexores metacarpi. Flexor, perforans and perforatus. RADIUS. Flexor brachii. Humeralis obliquus. Extensor metacarpi, magnus and obliquus. Extensor pedis. Extensor suffraginis. Radialis accessorius. UINA. Triceps extensor brachii. Scapulo-ulnaris. Anconeus. Flexor metacarpi medius. Ulnaris accessorius. Humeralis obliquus. Extensor suffraginis, TRAPEZIUM. Flexor metacarpi, extenius and medius. METACARPUS. LARGE BONE. Extensor metacarpi magnus. EXTERNAL BONE. Flexor metacarpi externus, INTERNAL BONE. Extensor metacarpi obliquus. Flexor metacarpi internus, DIGIT. Extensor pedis (three phalanges). Extensor suffraginis (1st phalanx). Flexor perforatus (2nd phalanx). Flexor perforans (3rd phalanx). PELVIC LIMB. OS INNOMINATUM. Longissimus dorsi. Compressor coccygis. Four Abdominales. Three Glutei. Tensor fasciae latae. Rectus femoris. Rectus parvus. Obturator, externus and internus, Pyriformis. Two Gemelli. Iliacus. Psoas parvus. Quadratus lumborum. Gracilis. Sartorius. Pectineus. Triceps adductor femoris. Triceps abductor femoris. Biceps rotator tibialis. Ischio-femoralis. FEMUR. Psoas magnus. Iliacus. Three Glutei. Obturator, externus and internus: Pyriformis. Two Gemelli. Tensor fasciae latae. Vastus, externus and internus. 260 COMPARATIVE MYOLOGY. Rectus pai'vus. Crureus. Pectineus. Triceps adductor femoris. Triceps abductor femoris. * Ischio-femoralis. Gastrocnemius. Flexor perforatus. Extensor pedis. Flexor metatarsi. Popliteus. TIBIA. Sartorius. Gracilis. Triceps abductor femoris. Biceps rotator tibialis. Flexor metatarsi. Plantaris, Popliteus. Flexor perforans. Flexor accessorius. FIBULA. Peroneus, Flexor perforans. PATELLA. ^ Tensor fasciae latse. Quadriceps cruralis. Triceps abductor femoris. TAESUS. CALCANEUM. Gastrocnemius. CUBOID AND SMALL CUNEIFORM, Flexor metatarsi. METATARSUS. LARGE BONE. Flexor metatarsi. DIGIT. Extensor pedis (three phalanges). Flexor perforatus (2nd phalanx). Flexor perfoi-ans (3rd phalanx). COMPARATIVE MYOLOGY. A.N extensive section devoted to this subject would be somewhat out of place in an ordinary class-book ; • therefore for fuller descriptions and details the student must have recourse to exhaustive works of reference, or, what is still better, to his own dissections and observations, bearing in mind the typical branch of the subject. We shall endeavour to point out where the more important muscles of the domesticated animals present features which, for our purpose, are worthy of comparison with those of the selected type ; and in this attempt we observe very generally the same sequence as to regions and groups that we have adopted in describing the muscles of the horse. RUMINANTIA. Subcutaneous Region. The panniculus carnosus in the cervical region is mostly aponeurotic ; a muscle which resembles the sterno-niaxillaris of the horse is sometimes regarded as constituting its inferior tieshy portion. In the head it resemblefi that of the horse, but there is a fleshy expansion in the frontal region — the so-called frontalis muscle — which is apparently a part of the panniculus. In the trunk there is no very important deviation from the arrangement already ■described. RUMINANTIA THE TRUNK. 261 The Head. In the ruminant the palatine ridges being closer together, the pterygoid inuscles originate nearer to the median line of the head, and thus produce more lateral motion in the lower jaw than there is in that of the horse. There is no digastric muscle in the domesticated animals other than the horse, the muscle representing it having only one belly ; in the ox it is joined to its fellow on the other side by a small, square, transverse muscle. The massetcr and temporalis are both less strong. Passing from the root of the horn core to the upper edge of the orbital fossa is a flat thin muscle, the frontalis, which blends with the external levator of the evelid ; it is, perhaps, a portion of the panniculus. The levator labii superioris alceqne nasi is not present in the smaller ruminants, and in the ox it differs in that the anterior, instead of the posterior division, covers the dilatator naris lateralis, and that it covers the nasalis longus as well. Two accessory muscles arise in common with the last named, and go to the upper lip. The dilators of the nostril, except the lateralis, are wanting. The zygomaticus has a long tendon of origin reaching up to the zygoma. The long tendon of insertion of the depressor labii inferioris is wanting. The hyoideus magnus has a long tendon of origin, and it forms no sheath, there being no median digastric tendon. The lachrymalis is closely blended above with the anterior border of the orbicularis palpebrarum, and is more developed and thicker than in the horse. The Trunk. The muscle which would appear to correspond to the sterno-maxillaris of the horse, is considered by Chauveau as representing the inferior fleshy band of the panniculus carnosus ; it is attached superiorly, not to the angle of the maxilla, but to the fascia of the masseter muscle, and sometimes it may be traced to the zygoma. This view being taken, the sterno-maxillaris finds its representative in the sterno-suboccipitalis, a muscle which becomes inserted to the basi-occipital bone in company with a tendon of the levator humeri The sterno-thyro-Tiyoideiis is larger than in the horse, and not digastric. The rectiis capitis a^iticus major is covered by the trachelo-atloideus, a flat muscle joining the atlas inferiorly to some of the succeeding vertebrae. The levator humeri is attached anteriorly to the mastoid process, to the posterior surface of the occipital bone and the ligamentum nuchse, to the basi- occipital bone together with the sterno-suboccipitalis, and to the wing of the atlas by a tendon separate from that of the splenius and trachelo-mastoideus. In ruminants the splenius is very .small ; in the camel it is stated by Cuvier to be non-existent, or at least so small as to escape observation. In the costal and dorso-lumbar regions there is little that merits comparison ; Ave may, however, note that the trapezius and serratus magnus are largely developed ; also that the intercostales and levatores costarum of course vary in numbei- with the ribs. The pectoralis antictis is small, and blended con- siderably with the transversus. The abdominal tunic is large and very thick, its development being always proportional to the magnitude of the abdominal viscera The linem transverse^ 'Oi the rectus abdominis are very well marked. The obliquus internus is large. 262 COMPARATIVE MYOLOGY. and fills up the space between the ilium, the last rib, and the lumbar verte- bra;. The fascia t ran sver sails' is better marked than in the horse. In the muscles of the sublumbar region, no comparison is necessary. The diaphragm in ruminants is thick and strong, being propor- tionate to the weight of the ab- dominal viscera, which it is its function to compress and force backwards. The crura are both long and large, and the periphery is attached more anteriorly than in the horse In the camel the diaphragm usually contains a small bone. Pectoral Limb, The extensors of the metacarpus are disposed as in the horse, ex- cepting that the tendou of the obliquus is inserted to the great metacarpal bone. The extensor pedis is divided throughout its length, giving rise to an external muscle, the extensor communis digitorum, and an internal one^ the extensor proprius internus, the former being rather larger than the latter. The tendons of these muscles run down the metacarpus in company,and at the commence- ment of the digits that of the extensor communis bifurcates, a portion being inserted to the pyramidal process of each distal phalanx. The tendon of the extensor proprius internus re ceives slips Irom the suspensory ligament about the middle of the first phalanx, and is attached to the median, and outer surface of the internal distal phalanges. The extensor suffraginis becomes, in thQr\xm.\fia.niyi\iQ extensor proprius externus, diflfering from the former muscle of the horse in being thicker and stronger, and in being inserted in the same manifer as the internus. Tliese three muscles are all extensors, but the Fio. ST. Tendons and ligaments of left anterior extremity of Ox, viewed from external side, a. Flexor perforatus tendon ; a', Its superficial ; a", Its deep branch ; 6, In- terosseus metacarpeus ; c. Flexor perforans tendon ; d-d", e-e'", Superior suspensory ligament and attach- ments ; d, anterior division ; d', Its superficial branch, blending at d" with extensor proprius tendon ; e, Deep branch of posterior divisiou ; e', e". Branches forming superior ligaments of small claw ; e'", Inferior liga- ment of small claw; />_ Common annular ligament; 0, o', Superior and inferior special annular ligaments ; It. Interdigital ligament ; i, i'. Tendon of the extensor proprius externus. OMNIVORA SUBCUTANEOUS REGION. 263 communis is also an approximator, ■while the proprii are divertors or expansoi-s of the digits. The flexor perforatus is a double muscle, but unites to form a single tendon, which divides, and each part behaves as the single portion in the horse, being however assisted in the formation of the sheaths for the per- forans tendons by two strong slips from the suspensory ligament, which corre- spond to the check ligament. In effect the check ligament may be said to be attached in the ruminant to the perforatus tendon only. The tendon of the flexor perforans also divides, the two parts passing through the sheaths formed as above described, and terminating in a similar manner to that of the horse,, becoming however blended with the plantar cushion of the foot, and the inferior interdigital ligament. Pelvic Limb. The gluteus externus is intimately blended with the triceps abductor. The maximus is nearly covered by the above compound muscle and that of the fascia lata, and is smaller than in the horse, while the internus, on the other hand, is larger. The tensor fascice latcs and triceps abductor become firmly united over the region of the trochanter major, the former muscle being largely developed, while the latter has no femoral attachment. The rectus parvus is wanting. The biceps rotator tibialis has no sacral origin. There is no pyriformis muscle, but a muscle has been described, pursuing a similar course outcide the pelvis, .and so far corresponding to it. The tendon of the obturator internus passes through the obturator foramen. The fibrous portion of the flexor metatarsi, and the extensor pedis of the horse have in the ox a common tendon of origin, giving rise to three large muscles of which the external one is the extensor communis digitorum, and the internal the extensor proprius internus, the tendons of these two terminating as in the anterior limb. The third muscle, situated before, and somewhat to the inner side of the others, is a flexor of the metatarsus, and represents the fibrous portion of the flexor metatarsi in the horse, forming a sheath or ring through which passes the tendon of the tibialis anticus, a muscle rejjresenting the fleshy portion of the same. The peroneus becomes the extensor proprius externus, and is attached distally as in the fore limb. A muscle which has no representative in the horse is one which has been named the peroneus longus lateralis. It arises, deeply seated, from the external part of the head of the tibia, and terminates in a long slender tendon which winds obliquely over that of the proprius externus at the tarsal joint, and after pursuing a tortuous course round the outside of the joint, is inserted to the small cuneiform and metatarsal bones. The flexor perforatus of the ruminant is thicker in the fleshy portion than that of the lioise, and the flexor perforans is more clearly divisable into two parts. OMNIVORA. Subcutaneous Region. In the hog the cervical portion of the panniculus carnosus is double, one part arising from the cariniform cartilage of the sternum, and the other from the 264 COMPARATIVE MYOLOGY. external scapular region. Anteriorly the parts unite, and the muscle expands over the face, joining its fellow of the opposite side. The Head. The levator labii superioris alceque nasi, dilatator naris transversus, and lachry- malis are wanting, but the nasalis longus is well developed. The retrahens exlernus has two tendons of insertion, one proceeding to the conchal, the other to the scutiform cartilage. The Trunk. The inferior portion of the levator humeri is attached by one tendon to the occipital protuberance, and by a second to the mastoid crest, the superior portion going to the wing of the atlas. ^ The sterno-thyroideus is double, having two attachments to the thyroid cartilage. The longus colli, instead of being a single muscle as in the horse, is separable into right and left portions. The scalenus extends far backwards, usually reaching the third rib. In the costal region we have merely to note that the trapezius is largely developed ; the latissimus dorsi is also large, and presents digitations by which it becomes attached to the ribs it covers. The pectoral muscles resemble those of the ox. In the dorso-lumbar region we find that the longissimus dorsi is divisible into a transverse and a costal portion. The abdominal tunic is a mere fold of cellulo-fibrous membrane, while the obliquus externus presents a large fleshy, and a small, or rather narrow, aponeurotic portion. In the sublumbar region the muscles of the omnivora, like those of the ruminants, present no features worthy of comparison with those of the horse ; the diaphragm also calls for no special comment. Pectoral Limb. The/ea;or brachii at its insertion gives off a tendon which passes to the ulna, and is attached to the lower part of the olecranon, and close by is attached another slip from the humeralis obliquus. The coraco-humeralis is short, very tendinous, and consists of only one portion, which is inserted just above the insertion of the teres internus. The scapulo-ulnaris is continuous with the latissimus dorsi. The extensor metacarpi magnus is inserted to the inner large, the obliquus to the inner small metacarpal bone. The extensor communis tendon divides into four parts, one being attached to either distal phalanx ; and the extensor proprius internus tendon bifurcates, and goes to the distal phalanges of the two inner digits, the proprius externus joining the two outer ones in a similar manner. The fiexor pedis perforatus is double, both as to its fleshy portion and its tendon ; a part becomes inserted to the median phalanx of each of the large digits, while the tendon of the flexor perforans divides into four parts, one being inserted to each distal phalanx. In the metacarpal region there are four interossei or interosseous palmar muscles, which arise superiorly from the back of the metacarpal bones and ligaments, and terminate each in two small sesamoid tendons, which afterwards CARNIVORA THE TRUNK. 265 -wind round to the front of the bone, and join the chief extensor tendon of theLv own digit. These muscles are the analogue of the svspensory ligament in the horse and ox, as they perform a similar function. A single large lumbricalis joins the flexor perforans tendon of the internal digit to the extensor proprius tendon of the same ; and on the outside another muscle runs from the carpo- metacarpal ligament to the extensor proprius tendon of the outer small digit, i-egarded by M. Chauveau as the representative of the flexor brevis minimi ■digiti of the dog or the human subject. Pelvic Limb. In the gluteal and femoral regions the muscles resemble those of the ruminant ; the adductor magnus and biceps rotator have however a very slight attachment to the coccyx. The tendon of the extensor communis digitorum Thich there is in the dog only on? set, the palmares j they are four in number, and disposed in the same way as in the hog. The himhncales are exceedingly slender, and situated between the branches of the perforans tendon, from which they arise ; they are continuea by delicate tendons, whose attachment is uncertain ; they may be traced sometimes to the extensor tendons of the three outer digits ; their use is obscure. Connected wdth the pollex are three comparatively rudimentary muscles — an abductor, an adduc- tor, and a flexor. The abductor brevis pollicis is a very small muscle, directed downwards and outwards ; arising from the posterior carpal ligament, it is inserted to the metacarpal element of the pollex, which it abducts and also flexes. The opponens jjollicis, placed below and beneath the last, is large in the human subject, but very rudimentary in the dog. It has attachments similar to those of the last-named muscle, bvit is inserted more to the inside ; it is an adductor, opposition of the thumb being impossible in the dog. The flexor brevis pollicis is rather longer than the preceding muscle, but very slender ; it arises also from the posterior carpal ligament, and is inserted to the proximal phalanx of the pollex, of which it is the chief flexor. The ■adductor indicis is a long prismatic muscle, situated in the depression between the two interossei ; arising from the posterior carpal ligament, it is inserted to the proximal phalanx of the index or first digit, at its supero-ihtemal part. Like the pollex, the outer digit has three special muscles, an abductor, an adductor, and a flexor. The abductor minimi digiti is situated outside and behind the outer metacarpal bone; it arises from the trapezium, and is inserted by a long tendon to the supero-external part of the proximal phalanx of the outer digit. As its name implies, it is an abductor. The adductor (opponens) minimi digiti, long and flat, arises close by the adductor indicis, passes downwards and outwards, and its tendon is inserted as that of the abductor muscle, but to the inside of the bone ; it adducts the digit. The flexor minimi digiti is placed on the inner side of, and below the abductor of the same digit. Triangular and flat in form, it arises from the inferior unci- form ligament, joining the tendon of the abductor. The palmaris brevis, or cutaneous palmar, is a thick and rounded semimuscular mass, situated behind and below the carpus, adhering intimately to the skin, and being deeply attached to the fascia of the subjacent muscles. In the felidce the claw is retracted by a ligament of yellow elastic tissue. " The apparatus for the retraction of the ungual phalanges is so well developed that the claws are completely retracted within sheaths of the integument, when the animal does not desire to use them. To this end the elastic ligaments are very strong, and the median phalanx is excavated in order to allow of the lodgment of the retracted phalanx on one side of it." — (Huxley.) Pelvic Lemb. The gluteus externus is very large, the maximus comparatively small ; the latter does not extend before the iliac crest, and it is inserted by a single tendon. The two parts of the triceps abductor fern oris are closely blended, and 268 COMPARATIVE MYOLOGY. the auterior one has no ischial origin. The sartor i us has an origin from the venter of the ilium, and its fleshy portion reaches the tihia. The gracilis i* very small and thin. In the anterior tibial region we find the following muscles : — The tibialis aniicus, corresponding to the fleshy portion of the flexor metatarsi, partly covers the extensor communis ; it arises from tTie tibial crest and tuberosity,, receives a slip from the peroneus, and is inserted by a tendon to the meta- tarsal element of the hallux. If the hallux is complete, a tendinous slip passes to the distal phalanx. The tendon of this muscle is bound down by a fibrous band, from which a strong slip passes imder the tendon, becoming attached to the tibia, and to the metatarsal bone of the middle digit, to some extent corresponding to the fibrous portion of the flexor metatarsi. The extensor communis digitorum arises by a strong tendon from between the femoral condyle and the trochlea ; its tendon of insertion passes over the tarsus much in the usual manner, divides into four slips, and is inserted as in the anterior limb. The ijeroneus longus is placed between the preceding muscle and the peroneus brevis ; it arises from the superior part of the tibia, and its tendon, reaching the tarsus, divides, a slip passing inwards to the first meta- tarsal bone, the rest winding roimd the cuboid to gain the back of the joint, and become attached to the metatarsal bone of the hallux. This muscle seema to be an abductor of the extremity. The peroneus brevis consists of two parts. — a superior, arising from the upper third of the fibula, and having a long thui tendon, which passes underneath the peroneus longus, descends and joins the extensor tendon of the external digit. The inferior part is permiform, and arises also from the fibula, ending in a strong tendon which is inserted to the external metatarsal bone. The superior portion is the extensor proprius of the outer digit, the inferior an abductor of the extremity. In the posterior tibial region we find the plantaris wanting. The flexor perforatus is somewhat blended with the gastrocnemius, and its tendon is divided into four parts, and inserted as in the anterior extremity. The perforans tendon divides into four, and if the hallux is perfect into five slips, proceeding to the distal phalanges. Between the perforans and flexor accessorius is a separate muscle, the tibialis posticus, very tliin and slender, arising from the fibula and tibia above, its tendon accompanying that of the accessorius into its sheath, and afterwards becoming blended with the posterior tai'sal ligament. We note the following muscles in the metatarsal region. The extensor pedis brevis consists usuallj^ of three bundles, and it joins the extensor tendons of the three outer digits. The perferans has a small accessory muscle, which arises on the outside of the tarsus. The lumbricales and interossei resemble their ana- logues of the metacarpus. The muscles proper to the hallux are either absent, or too rudimentary to merit notice. An abductor minimi digiti is present^ and corresponds to that of the metacarpus. RODENTIA. The most prominent feature in the myology of the rabbit is the enormoua development of the dorso-lumbar, sublumbar, gluteal, and femoral muscles. RODENTIA AVES. 269 The longissimus dor si is attached to the maramillary processes of the lumbar vertebrae. The muscles of mastication are also well developed, especially the masseter. The muscles of the limbs bear a general resemblance to those of the dog. In the fore-arm there is no rotation, hence we find the supinator longus and pronator quadratus wanting ; the other rotators being small, and acting as mere flexors of the elbow joint. AVES. A remarkable feature in the muscular system of birds is the liability of the tendons to ossification, and this condition is by no means peculiar to old animals. Comparing, in the wide sense, the muscles of a bird with those of a mammal, we are struck with their wonderful morphological siijailarity, although the peculiarities of the skeleton, and physiological characteristics of the animal lead to various deviations in their form and development. The muscles of the pectoral limbs, and notably those of the pectoral group, are the muscles of flight. There are two pectoral muscles, which may be called the magnus and parvus. The magnus, an enormous muscle, is the depressor of the wing (depressor alae) ; it is placed posteriorly, arising from the whole of the sternum, carina, and last ribs, and being inserted to the humerus near its head. The pectoralis parvus (levator alse) is small, and situated in the depression between the clavicle and coracoid bone, its tendon of insertion passing inside and over the neck of the scapula^ as over a pulley, and becoming inserted to the humerus ; this is the levator of the wing. A peculiar arrangement of the muscles enables the perching birds to "roost." A kind of ligament passes over the front of the knee joint and joins the flexor tendon, so that when the tibia is flexed on the femur, the digits are also flexedj Hence during sleep, when the weight of the animal flexes the knee-joint, simultaneously it causes the digits to clasp the perch. The diaphragm in birds is said to assist both in. the dilatation of the lungs, and of the air sacs. Some authorities, however, dispute ita existence, othera again describe it as rudimentary. CHAPTER IV. SPLANCHNOLOGY. This section of the subject treats of the viscera, or organs which occupy chiefly the cavities of the body, and compose respectively the digestive, respiratory, urinary, and genital systems, all of which communicate with the outside world by apertures on the surface of the body. We will describe these systems in the order here given, first noting that in all of them there is a certain similarity in structure, in so far that each consists of a tube oi canal, lined by mucous membrane, and provided with various glands and other accessory organs. Before treating of these systems, it will be advisable to alludt briefly to certain tissues and structures which are closely associ- ated with them. These are epithelium, mucous and serous membranes, and glands. Involuntary muscular tissue which occurs extensively in these organs has been alluded to already. (See p. 157.) EPITHELIUM. This is a tissue cousistiug chiefly of cells, which, in one form or other, covers all the free surfaces of the body — i. e., the skin and mucous membranes ; one variety of it also covers the inner surfaces of closed and air-tight membranous sacs, the serous and syno- vial membranes, in which case it is dis- tinctively known as endotkelium. The following varieties of epithelium are de- scribed : — squamous, columnar, sphe- roidal, and ciliated. Squamous, tesselated, pavemental, or scaly epithelium consists of flattened scaly cells, usually arranged in superimposed layers. In shape irregularly oval, these cells vary somewhat, those on the surface being more 270 Fio. 88: Detached epithelium cells from the mucous membrane of the mouth, a. Cell wall ; h. Nucleus ; c, Nucleolus. EPITHELIUM. 271 fattened tlian tliose of the deeper layers, which are more spher- ical in form. They contain protoplasm, a nucleus, and a number of granules. The superficial cells are evontually cast off, the deeper ones taking their place, and the latter become more and more flattened as they approach the surface. Consisting thus of layers or strata of cells, the name stratified epithelium has been applied to this tissue; it is found in the alimentary mucous membrane, from tLe mouth to the first half of the stomach, in the bladder, the rectum, the entrances to the nose, the eye, urethra, and vagina, and in a dried and desquamating form it constitutes the epidermis or scarf skin ; it is non- vascular, and for the most part non-sensitive. Endothelium. — This resembles epithelium in structure, differ- ing in its situation, as above described, and in the fact that it is arranged as a single layer of flattened cells. Columnar or cylindrical epithelium. — In this variety the cells are cylindrical in form, and arranged side by side, with their long axes perpendicular to the subjacent surface. Their contents resemble those of the squamous kind, but the nucleus is more distinct. This form of epithelium is found on the mucous membrane of the intestines and pyloric half of the stomach, and it is continued into the ducts of the glands which open on the surface of the membrane. The cells covering the villi of the intestine have expanded free extremities, which may appear slightly striped. Spheroidal or Polyhedral epithelium is found in the follicles and ducts of glands, hence the name glandular epithelium. The cells of this variety are spheroidal, or it may be irregularly polyhedral in shape. A variety known as transitorial occurs in ihe mucous membrane of the urinary bladder, the cells being transitional in form between those of columnar and scaly iinds, and arranged in a small number of layers. Ciliated epithelium consists of columnar cells, provided at their free extremities with delicate hair-like processes or cilia, which wave to and fro in a marked manner. The motion is apparently independent of the direct influence of the nervous system, since it is observable for some time after the death of ciliated epithelium, highly magnified. a, Nucleated cells ; 6. Cilia. 272 SPLANCHNOLOGY. the animal. This tissue is found in the mucous membrane^ of the air-passages, where its cilia tend by their motion to expel particles of foreign matter which are inhaled with the breath ; it is found also in the ventricles of the brain, in the canal of the spinal cord, and in the mucous membrane lining the uterus and Fallopian tubes of the female, and part of that lining the vas deferens of the male ; and in the convoluted uriniferous tubes. MUCOUS MEMBRANES. These structures are widely diffused, lining the canals of the four systems now under consideration, and becoming continuous with the skin at each of their orifices. A mucous membrane con- sists of one or more layers of epithelial cells placed upon a sub- epithelial layer or corium, the latter consisting of a modified form of connective tissue, and serving as a matrix in which are situated the nerves and vessels of the membrane, together with numerous glands. Some authorities have described a membrane separating the cellular from the vascular layer, and it has received the name of the basement membrane. By others it is regarded as a mere condensation of the corium. The secretion of the glands proper to the mucous membranes is mucus, a viscid fluid which lubri- cates their free surfaces. The surface of a mucous membrane may be smooth, as in the air-passages, or it may be papillated — i.e., furnished with small projections, papillae, as in the tongue ; it may be rugeous, or thrown into folds or rugas, as in the oeso- phagus and stomach ; in the small intestine it presents finger-like projections termed villi, and is then said to be villous, and in the same situation the membrane presents valve-like folds, and may be termed valvular. The mucous membrane which lines the digestive canal becomes continuous in the pharynx Avith that lining the respiratory canal, the pharynx being a cavity common to the two systems ; hence the entire membrane may be termed the gastro-pulmonaoy mucous membrane, which is also produced so as to line the Eustachian tube and tympanic cavity of the ear, and is, in some animals, continuous by means of the lachrymal duct with the conjunctiva of the eye. At the lips and anus it is directly con- tinuous with the skin. In a similar manner, the mucous mem- brane of the urinary canal becomes continuous with that of the SEROUS MEMBRANES. 273 genital eanal in the vagina in the female, in the urethra in the male; the membrane so formed is termed the urino-genital mucous membrane, and it becomes continuous with the skin at the orifices of these organs. Mucous membrane also lines the ducts of the mammary glands; and in fact the ducts of all glands which open on the skin or mucous membranes. SEROUS MEMBRANES. The closed cavities of the body are lined by membranous structures of this class. By a closed cavity we understand a receptacle impervious, under normal circumstances, to the atmo- spheric air. A serous membrane consists of an endothelial and a subendothelial portion, the cells of the former being arranged in a single layer. Synovial membranes may-be regarded as a variety of serous membranes, differing chiefly in the nature of their secre- tion ; they have already been described (see p 125). Since a serous raembrane is so arranged as to line a closed cavity, and at the same time to cover its contents, it follows that the entire membrane must form a closed sac, the endothelial layer being on the inside ; such a sac is called a serous sac or cavity. The fold of the membrane which lines a cavity is called the parietal, that which covers its contents the visceral portion ; the two surfacea contacting, and gliding readily upon each other, are lubricated hy a fluid secretion contained in the sac ; hence one use of these membranes is to prevent friction between the walls of cavities and the organs contained therein. The following are the serous membranes and their position in the body : — The arachnoid membranes form closed sacs, situated, one between the two cbverings of the brain, the other between those of the spinal cord. The peritoneum lines the abdominal cavity and covers its viscera; the pleurae, right and left, each covers the lung, and lines the half of the thoracic cavity of its own side. The peri- cardium lines the fibrous sac which contains and supports the heart, and also covers the latter. The cavities of the heart are also lined by a membrane of a serous nature — the endocardium — which is continued through the veins and arteries; as the chief lymphatic vessels communicate with the venous system, the endothelial lining of the former becomes continuous with that of the latter. Lymphatic vessels open into the serous sacs by very small apertures, or stomata, so that these sacs are now con- T 274 SPLANCHNOLOGY. sidered as being depositories of lymph ; and " thus a continuity of surface is established between the serous membranes and the lining membrane of the blood-vascular system through the lymphatics " {Turner). GLANDS. Without attempting an exhaustive definition of the glands, it may suffice to state here that for the most part they are organs in which is carried on the process of secretion, or separation from the blood of certain matters, which may be required to assist in the various vital functions, or may be destined to be speedily cast off as effete or poisonous material. Most glands in their typical structure resemble a mucous membrane, consisting of epithelial, subepithelial, vascular, and nervous portions ; the first of these portions usually rests upon a condensed layer of the second, which is known as the Tnembrana propria, or basement mem- brane. The vessels supply the gland with blood, from which the secretion peculiar to the gland is separated by the vital power of the cells, which power is stimulated by the nerves, the latter also regulating the blood supply. Lymphatic vessels are present, but their use in these organs is obscure. The sub- epithelial tissue supports the other component structures of the gland, at the same time determining its anatomical form. The secretions of glands are, as a rule, discharged on the free surfaces of the body — i.e., on the mucous membranes or skin — by means of tubes known as the gland-ducts ; hence such glands may be conveniently regarded as depressions in the mucous membrane or in the skin. When a gland appears as a tube-like depression in the mucous membrane it is termed a follicle, crypt, or simple tubular gland ; if the cavity is dilated, it is known as a sac, or saccular follicle ; and if either of these forms be provided with secondary recesses, it is said to be multilocular. A tubular gland may be coiled upon itself; or it may branch, in which case it becomes a compound tubular gland. A tubular depression ending in a number of vesicular recesses constitutes a simple racemose gland ; a compound racemose or conglomerate gland consists of a number of simple ones with a common duct. The ductless glands form a group which difiers from any of the above in the absence of a duct, the secretion usually being EXPLANATION OF PLATE IV. Digestive Apparatus of the Horse, 1. Mouth. 11. Small intestine. 2, Pharynx. 12. Floating colon. 3. (Esophagus. 13. Eectum. 4. Diaphragm. 14. Anus. 5. Spleen. 15. Left kidney atid ureter. 6. Stomach (left sac). 16. Bladder. 7. Duodenum. 17. Urethra. 8. Liver (upper extremity). A. Hard palate. 9. Great colon. B. Tongue. tO. Caecum. C. Soft palate. D. Trachea. E. Pulmonary artery (divided). F. Heart. G. Posterior ac rta. THE ALIMENTARY CANAL. 275 -carried away by rapture of the glandular sac, or by absorption into the neighbouring lymphatics. The liver has been termed a reticular gland, because its ducts form a network at their origin. Digestive System. The" digestive organs comprise the alimentary canal and its accessories, by which the alimentary matter is received and sub- jected to specific actions, which adapt it for purposes of nutri- tion. Digestion therefore embraces the collective operations and changes which the food undergoes in the alimentary canal. The functional processes of digestion are — Prehension, the taking up of food, which is performed in the horse by the lips ; Mastication, chewing, grinding ; and, simultaneously with this, Insalivation, or mixing the ingesta with the fluid secretion of the salivary glands ; Deglutition, or swallowing the prepared food by means of the tongue, pharynx, and oesophagus ; Ghymifica- tion, or conversion of food in the stomach into a pultaceous chyme, by maceration and the action of the gastric juice ; Chylification, or conversion of the chyme into chyle, a change which takes place in the duodenum, presumably "by the agency of the biliary and pancreatic secretions; Absorption of the nutrient material into the circulation ; and finally, Defecation or excretion, the expulsion of residual inert matter. THE ALIMENTARY CANAL. The alimentary canal is a musculo-membranous tube extend- ing from the lips to the anus ; its walls are composed of muscular tissue, for the most part of the non-striated kind, and lined throughout by mucous membrane. It consists of a continuous series of tubes and cavities, the chief of which -are the Mouth, Pharynx, CEsophagus, Stomach, and the Intestines. It may be divided into three portions — the preparatory, or ingestive, embracing the mouth, pharynx, and oesophagus, in which the food is prepared ; the essential, or digestive, including the stomach and most of the intestines, where the food passes through various changes, and is deprived of its nutritive por- tions; and the egestive, or expulsive portion, by which the residue is expelled from the system. Each division is provided 276 SPLANCHNOLOGY. with accessories, the preparatory with teeth and salivary glands^ and the essential organs with the liver, pancreas, spleen, &c. We will describe the parts of the alimentary canal in the order above given — the order in which the food traverses them. THE MOUTH. The mouth is an irregularly oval cavity at the commencement of the alimentary canal, containing the organs of taste and the instruments of mastication ; it is situated between the jaws, its long diameter following that of the head. It is pierced by two openings ; the anterior for the introduction of food, and the posterior, through which the latter passes into the pharynx. It is bounded in front by the lips and their aperture, the fissura oris, and laterally by the cheeks ; the roof is formed by the hard palate ; its floor is occupied by the tongue, while the posterior boundary is the veluTYi pendulum palati, or soft palate, a mem- branous partition separating it from the pharynx. The mucous membrane is pale, roseate, continuous with the skin at the lips, and covering the whole free surface of the mouth and its contents, excepting the teeth. THE LIPS. The labia, or lips, superior and inferior, are movable fleshjr curtains surrounding the anterior opening, and united laterally by a commissure. They consist of skin and mucous membrane, Avhich enclose muscles, vessels, nerves, areolar tissue, fat, and certain labial glands situated between the mucous membrane and muscle. The mucous surface of each lip is bridled mesially to the gum by a doubling of the membrane, constituting the fra^num labii superioris and inferioris. The arterie-^, and veins of the lips are the palato-labials and the superior and inferior coronaries. The nerves come from the fifth and seventh cranial pair, the first supplying the sensory, or nerves of feeling, which are well developed in the lips of the horse, since these are organs of touch as well as of prehension. THE CHEEKS. The buccal, or cheeks, are two musculo-membranous walls, -which close the mouth laterally ; they are continuous with the THE SOFT PALATE. 277 lips, and consist of an external cuticular, a central muscular, and an internal mucous coat ; the latter is termed the buccal mem- brane, and . is provided with numerous small buccal glands, similar to the labial ones, which open on its surface by straight projecting pointlets ; a few larger ones are known as the molar glands. On the buccal membrane of each side, near the third upper molar tooth, is a papilla, in which is the opening of the duct of the parotid gland. The gingivce, or gums, are reflections of the buccal membrane, and contain dense fibrous tissue, con- tinuous with the periosteum of the alveolar processes, with an epithelial covering ; they embrace, without being attached to, the necks of the teeth, and are reflected into the alveoli. The chief arteries and veins of the cheek are the facial and the coronaries. The nerves come from the same source as those of the lips. The cheeks by their muscles serve during mastication to support the food, and press it between the molars. THE HARD PALATE. The hard palate, or mouth-roof, is Ibounded anteriorly by the incisor teeth, posteriorly by the soft palate. It is firmly attached to the bony palate, formed by the palatine bones and palatine processes of the superior and premaxillse. It consists of a dense layer of mucous membrane, with a thick subjacent layer of fibrous tissue. It is equally divided by a longitudinal groove corresponding to the palatine suture, which originates anteriorly at the base of a small tubercle. From this raphe spring trans- verse ridges, which divide the palate into a number of arches with their concavities backwards ; they become smaller posteri- orly, and are from seventeen to twenty in number. The palate is supplied with blood from the palatine arteries, returned in a venous plexus, which forms a kind of erectile tissue in the submucous layer. The sensory nerves come from the superior maxillary division of the fifth pair. The hard palate furnishes a fixed surface, against which the tongue can mani- pulate the food. THE SOFT PALATE. The soft palate, or velum pendulum palati, is the valvular curtain suspended between the mouth and the pharynx, and it consists of a double fold of mucous membrane, enclosing muscles, glands, vessels, and nerves. It presents two surfaces and four 278 SPLANCHNOLOGY. borders. Its superior border is attached to the palatine arch, and is continuous with the hard palate, whence the velum passes downwards and backwards. The lateral borders are united to the line of demarcation between the cavity of the mouth and that of the pharynx. The inferior border is concave and free, resting upon, and closely embracing the base of the epiglottis. From the extremities of this border, two very thin prolongations run along the lateral walls of the pharynx as far as the beginning of the oesophagus; these are the 'posterior pillars of the fauces. Between the free border of the velum pendulum palati and base of the epiglottis is the posterior opening of the mouth, called the isthmus faucium, which in the horse, from the extreme development of the soft palate, is constantly shut, except during the passage of food or water. It is owing to the great size of the velum that a horse is unable to breathe through his mouth. The anterior surface of the velum forms the posterior boundary of the mouth, is marked by longitudinal folds and transverse lines, and studded with the mouthlets of numerous submucous glands. This surface is united laterally to the base of the tongue by large mucous columns, the posterior pillars of the tongue, or anterior pillars of the fauces. Behind these are two lateral triangular spaces, the tonsilar spaces, which take the place of the tonsils or amygdalce, these being absent in the horse; numerous gland ducts open in these spaces. The posterior surface of the soft palate is convex, and forms the anterior wall of the pharynx ; it presents three very small longitudinal ridges. MUSCLES OF THE SOFT PALATE. A strong layer of aponeurosis or fibrous tissue, the staphyline aponeurosis, forms as it were the foundation of the soft palate, being attached above to the palatine arch. The following muscles control the soft palate : — Teusor palati. I Pharyngo-staphylinus. Levator palati. | Palato-staphylinus. Palato-glossus. TENSOR PALATL {Peristaphylinus Externus.) (Fig. 90. i.) A long slender muscle with tendinous extremities, running longitudinally between the levator palati and the pterygoidei. It MUSCLES OF THE SOFT PALATE. 279 arises from the petrosal styloid process ; its tendon of insertion, playing over the staphyline groove, expands and becomes lost in the fibrous layer of the velum, of which it is a tensor and depressor. LEVATOR PALATl. ( Peristaphijlinus Internus. ) (Pig. 90. h.) A slender muscle which arises with the last-named one, and lies between it and the Eustachian tube. It passes directly to the soft palate expanding between the Pharyngo-staphylinus and the Palato-staphylinus, and finally joins its fellow of the opposite side. It raises the velum Fig 90. Right infero-lateral view of the muscles of the nia.\illary space ; the ramus and hyoid cornu are «nt away, a, Lingualis : 6 6, Hyo-glossus longus ; c, Hyo-glossus brevis ; d, Genio-hyo-glossus <, Genio-hyoideus : /, Stylo-hyoideus : g, Hyoideus magnus; 7i. Levator palati ; i. Tensor palati k, Pharyngo-staphylinus : I, Pterygo-pharsmgeus ; m. Kerato-pharyngeus ; n, Hyo-pharyngeus c, Thyro-pharyngeus ; p, Crico-pharyngeus : q, OEsophagus. PHARYNGO-STAPHYLINUS. {Staphylinus Communis.) (Fig. 90. i.) This is a broad, thin muscle, occupying the inferior half of the velum, and meeting its fellow in the median line ; they are sometimes described as a single muscle. The fibres run back- wards and outwards, and a portion, after following the free border of the velum, is continued under the pharyngeal raucous mem- 280 SPLANCHNOLOGY. brane and attached to the thyroid cartilage ; this portion helps to form the posterior pillar of its own side. This muscle is chiefly a tensor of the velum. PALATO-STAPHTLINUS. {Azygos Uvulce — Human.) This is a small cylindrical muscle contacting its fellow of the opposite side, and arising by a small tendon from the palatine arch and staphyline aponeurosis, to become attached to the free border of the velum at its middle ; the pair of muscles thus indicate the right and left halves of the structure. The action of this muscle is to raise and draw forwards the velum, thus helping to dilate the isthmus. PALATO-GLOSSUS. If this muscle exists in the horse, it will be found under the mucus membrane of the anterior pillar, which it helps to form, thus joining the soft palate and the tongue. The soft palate is supplied with blood by the staphyline and pharyngeal arteries. Its nerves come from the second division of the fifth pair, and from Meckel's ganglion. It acts as a valve between the niouth and pharynx, opening to allow the passage of alimentary materials during deglutition, but completely prevent- ing the return of such from the pharynx to the mouth ; hence in case of vomition in the horse the material is voided through the nasal chambers. Respiration is likewise effected in the solipede only through the nose. \ THE TONGUE. The tongue is a movable, musculo-membranous organ, situated on the floor of the mouth, between the rami of the lower jaw ; the space it occupies is termed the lingual canal. It is the special organ of iaste, and at the same time materially assists in mastication and deglutition. In the ox it is prehensile, and the carnivora lap or prebend water with it. The tongue consists of muscles, glands, vessels, and nerves, having its free surface enveloped by mucous membrane, which varies in thickness, LINGUAL MUSCLES. 281 being smootli and pellucid infero-laterally, where tlie ranine vein can be traced. Irrci^ularly pyramidal in shape, it has a root or base, a body, and an apex or tip. The base, the widest and thickest part, is muscularly attached to the OS hyoides and inferior maxilla; to the epiglottis by a fold of mucous membrane, the glosso-epiglottic ligament ; and to the velum pendulum palati by the anterior pillars of the fauces. The apecc, or tip, is free, and broa'd in the horse, being directed forwards against the inner surfaces of the lower incisors. The under surface of the tongue is attached anteriorly to the lower jaw by the genio-hyo-glossi muscles, and laterally by the reflec- tion of the mucous membrane, over the sublingual glands, to the inner surface of the inferior gums. Antero-mesially, the mucous membrane folds into a frcenura linguae, or anterior pillar, in front of which is a small papilla, containing the openings of the submaxillary glands ; and on either side, between the tongue and maxilla, are the ducts of the sublingual glands. The dorsum, or upper surface, is convex, and marked along its middle by a raphe, or groove, which indicates the division of the organ into two lateral halves. The raphe terminates near the base in a cavity known as the foramen coicum, or foramen of Morgagni, in which numerous mucous follicles open. Posteriorly the tongue is divided by fibrous tissue, which forms a partial longitudinal septem, commencing near the hyoid bone, and losing itself in the muscles. According to Briihl, a piece of fibro-cartilage exists here, peculiar to the solipede, and it has been named the lingual cartilage. LINGUAL MUSCLES. The substance of the tongue is composed chiefly of muscular layers running in different directions, between which adipose tissue is interposed. The muscles are divided into extrinsic and intrinsic. The extrinsic muscles of the tongue are as follows : — Hyo-glossus longus. Genio-hyo-glossus. Hyo-glossus brevis. Pharyngo-glossus. Hyo-glossus parvus. Palato-glossus. 282 SPLANCHNOLOGY. HYO-GLOSSUS LONGUS. (Stylo-glosstcs.) (Tig. 90, 6 h.) Situated along the border of the tongue, this muscle is long and flat. Origin. — From the external surface of the comu of the os hyoides. Insertion. — To the substance of the tongue expanding towards the tip. Relation. — Externally with the mylo-hyoideus and sublingual gland, sublingual nerve, and canal of Wharton ; internally with the genio-hyo-glossus and hyo-glossus brevis. Action. — With its fellow, to retract the tongue within the mouth ; singly, to draw it to one side. HTO-GLOSSUS BREVIS. {Basio-glossus.) (Fig. 90. c.) Situated on the inner surface of the hyo-glossus longus, it is a broad, flat, and somewhat radiating muscle, the fibres passing obliquely forwards and upwards. Origin. — From the side of the body and spur process of the os hyoides and the inferior part of the comu. Insertion. — The side of the tongue, passing inwards to form the " transverse fibres." Relation. — Externally with the mylo-hyoideus and hyo-glossus longus, the hypoglossal nerve, Wharton's canal, and the mucous membrane of the tongue ; internally with the hyoideus parvus and the corniculum, genio-hyo-glossus, the lingual artery, and the glosso-pharyngeal nerve. Action. — To draw the base of the tongue downwards and back- wards, on one side, or both if acting with its fellow. HYO-GLOSSUS PARVUS. Situated immediately under the mucous membrane,^intimately blended with the last named, this is a small radiating muscle. Attachments. — It arises from the inner aspect of the corniculum and hyoid bone, crosses the hyoideus transversus, its fibres then running forwards. It expands over the dorsum and sides of the tongue, its fibres crossing those of the hyo-glossus brevis. LINGUAL MUSCLES. 283 GENIO-HYO-GLOSSUS (Genio-glossus.) (Fig. 90. d.) Situated in the vertical median plane of the tongue, this is a broad, thin, and fan-shaped muscle, its fibres radiating upwards. Attachments. — Its basis may be said to stretch from the hyoid bone to near the maxillary symphysis, the radiating fibres passing upwards and some backwards, some forwards, buried in the sub- stance of the tongue. Relation. — Internally with its fellow ; inferiorly with the genio- hyoideus ; externally with the hyo-glossus longus and brevis, the sublingual gland, and the lingual artery. The anterior borders of this pair of muscles help to form the frsenum lingnse. Poste- riorly a certain amount of fat constantly occurs between them. Action. — This varies. It may protrude the tongue by depress- ing the dorsum, or help to retract it ; or it may depress the entire organ, according to the part of the muscle which acts, and to co-operation of the other muscles, PHARYNGO-GLOSSUS. This name has been applied to a few fibres which unite the tongue to the lateral wall of the pharynx, passing between the fibres of the genio-hyo-glossus and hyo-glossus parvus, and blend- ing with them, PALATO-GLOSSUS. (See muscles of the soft palate.) The intrinsic muscles are collectively described under the name LINGUALIS. (Fig. 90. a.) This muscle is arranged in two layers of locgitudinal, with an intervening set of transverse, fibres. The lingualis superficialis lies on the upper surface of the tongue just below the mucous membrane, running longitudinally from the apex nearly to the OS hyoides. The lingualis inferior, also longitudinal in direc- 284 SPLANCHNOLOGY. tion, is arranged in a rounded band, which extends in the inferior region of the tongue from base to apex, a few fibres reaching the hyoid bone. The lingualis transversus lies between the super- ficial and deep layers, intersecting the extrinsic muscles ; its fibres are always intermixed with a quantity of adipose tissue, and form the bulk of the organ. These layers alter the form of the tongue, the superficial tilting the tip upwards ; the inferior curves it down- wards; while the transverse protracts or elongates it. The fibres of the intrinsic muscles are regarded by Chauveau and others as prolongations of the' extrinsic muscular fibres. The mucous membrane is plentifully supplied with glands, simple and compound. The simple are mere follicles, secreting mucus. The compound glands, and certain closed follicles, are found chiefly at the base of the tongue, about the foramen csecum, posterior pillars, and papillae circumvallatse, into which many of their ducts open. LINGUAL PAPILLiE. The mucous membrane covering the under part of the free surface of the tongue is smooth, but as it passes over the borders it assumes a papillary character, and on the dorsum it is covered with papillae, which roughen and give it a velvety appearance. The papillae comprise three varieties : — papillae maximae, calici- form, or circumvallate ; mediae, or fungiform; and minimae, or filiform. The papillce circumvallatoe, three to five in number, are situated at the back part of the dorsum. They are arranged triangularly, the single one being posteriorly and mesially placed, corresponding to the foramen caecum. These papillae rest in cup- like depressions of mucous membrane, and are inversely conical, with the apex below ; several such papillae may be enclosed in the same calyx. The fungiform papillcB are more numerous, and scattered irregularly over the dorsum, being most numerous on the posterior third ; they are attached by a narrow neck, the base being round, free, and often furnished with filiform papillae. The filiform papillcB cover the greater part, but especially the anterior two-thirds of the dorsum, vanishing towards the base. They are simple or compound, the former having one free pro- cess, the latter more than one. Papillae are processes of the corium of the mucous membrane, containing terminal nerve filaments, numerous in the larger, but difficult to trace in tha PAEOTID GLAND. 285 -smaller, papillge. Like the mucous membrane, they are covered hy a thick layer of squamous epithelium, which is sometimes imbricated. It is generally believed that the caliciform papillae are subservient to the special sense of taste ; that the fungiform variety possesses common sensibility ; while the filiform papillae serve a mechanical purpose during the action of the tongue on the food. The blood-supply of the tongue comes from the lingual and sublingual branches of the glosso-facial artery, and the blood is returned by the lingual or ranine, and sublingual veins. The principal nerves are — the. lingual, or gustatory branch of the fifth ; the lingual branch of the glosso-pharyngeal ; and the hypoglossal or twelfth pair. Parotid and molar glands of the left side, a a, Parotid gland ; h b, Steno's duct ; c, Superior, and d. Inferior molar glands. SALIVARY GLANDS. The salivary glands are accessories of the mouth. They secrete the saliva, which is discharged into the mouth, and saturates the food, during mastication. There are three primary pairs — viz. the Parotid, the Submaxillary, and the Sublingual. PAROTID GLAND. This, the largest of the salivary glands, is long and flat, and is situated in the space bounded by the posterior border of the. 286 SPLANCHNOLOGY. inferior maxilla and tlie anterior border of the wing of the atlas i it lies immediately below the ear, which it partly surrounds, and is covered by the deprimens aurem. It is related internally with the guttural pouch, and inferiorly it occupies the angular space formed by the jugular and glosso-facial veins. It is greyish, and, like all salivary glands, conglomerate, consisting of a number of' lobes held together by dense areolar tissue, these again consist- ing of lobules, each of which is formed by minute vesicles, originating in the dilatation of the branched origins of th^' ducts. The latter unite t^ form larger ones, and terminate in Steno's duct, which commences at the antero-inferior surface. Fig. 92. Right infero-lateral view of the head ; the maxillary ramus, cheek, parotid gland, and upper lip Leing removed, a, Submaxillary gland ; b, Wharton's duct ; c, Sublingual gland ; d, Its excretory orifices ; e e, Labial glands ; /, Their excretory orifices ; g, Papilla, with orifice of Steno's duct ; h. Orifices of the superior, and, i, those of the inferior molar glands ; k, The hard palate ; I, The soft palate ; to, The tongue, with its papilla ; n, Pillars of the tongue and soft palate ; o, Fraenum- linguse. near the insertion of the sterno-maxillaris, passes ' along the posterior aspect of the digastricus, round the ramus of, the lower jaw, in company with, and posterior to, the glosso-facial artery and vein ; it thus runs along the anterior border of the masseter, and enters the mouth at about the level of the third upper molar tooth, the orifice of the duct being marked by a papilla on the buccal membrane. In some animals there is a small detached gland connected with it, the glandula soda paro- tidis, which opens into the parotid duct as it crosses the masseter. The duct consists of an internal mucous and an external con- tractile coat. MINOR SALIVARY GLANDS. 28^ The parotid gland is supplied with blood by numerous small arteries given off from larger vessels in the immediate neighbour- hood. The nerves come from the carotid plexus, also from the fifth and seventh pairs. SUBMAXILLARY GLAND. This gland, smaller than the parotid, is long, thin, and cres- centic, with the concavity directed forwards and upwards. It lies in the maxillary space, below and behind the parotid, and on the outer side of the pharynx, extending from the wing of the atlas to the body of the hyoid bone, where it terminates in Wharton's duct, which passes between the mylo-hyoid and hyo-glossus brevis, and is continued along the side of the jaw between the hyo-glossus longus and the sublingual gland, open- ing into -the mouth rather in front of the frsenum linguo3, where it is protected by a thick papilla on the mucous membrane, commonly called the harh. In structure it is similar to the parotid, but its lobes are larger, its attachments looser, and its duct- coats thinner. LUce the parotid, this gland receives many small arteries ; they come mostly from the external carotid and glosso-facial. The nerves are chiefly from the carotid plexus. SUBLINGUAL GLAND. This gland is smaller than the last-named, long, flat, and delicate. Situated under the tongue, it is placed longitudinally, with its edges vertical, and included between the mylo-hyoideus, hyo-glossus longus, and genio-hyo-glossus muscles ; its superior border reaches the mucous membrane of the floor of the mouth ; anteriorly it extends to the maxillary symphysis, posteriorly to the hyoidean spur process. In the horse it opens by from fifteen to twenty small ducts, the ducts of Rivinus, which are arranged along the floor of the mouth, on what has been termed the sub- lingual crest, each duct being marked at its opening by a papilla. UnUke the salivary glands hitherto described, the sublingual gland has a special artery of supply, the sublingual artery ; its nerves come from the gustatory nerve and carotid plexus. MINOR SALIVARY GLANDS. Other presumably salivary glands are the Molar, the Labial, the Lingual, and the Staph ylihe. The Molar glands, so called 288 SPLANCHNOLOGY. "because they are parallel to the rows of molar alveoli, are two in number, superior and inferior ; they are situated in the cheek, along the upper and lower borders of the buccinator. They dis- charge by numerous orifices in the buccal membrane. The Labial glands are placed under the mucous membrane of the lips, especially of the upper one. The Lingual glands are found at the base of the tongue, and partly along its sides. The Staphyline are situated in the soft palate, and between its anterior and posterior pillars, discharging into the mouth or isthmus faucium. Saliva, the fluid secreted by these glands, is clear, viscid, colourless, and slightly saline in taste, with a specific gravity of 1-005. Alkaline in reaction, it consists of water with about ■ one-half per cent, of solids, including fat, albumen, and a special nitrogenous principle, ptyalin, or " animal diastase," which helps to convert starchy material into grape sugar. Saliva also con- tains alkaline and earthy salts, with a trace of sulphocyanide of potassium. The secretion of the different glands varies ; that of the parotid is most watery, while that of the submaxillary and sublingual is viscid. The parotid secretes most abundantly during mastication, and always in direct ratio to the dryness of the food ; the others secrete equally, whether the aliment be dry or moist, but appear to be influenced by its taste. The sight or thought of food will frequently induce a secretion from the submaxillary and sublingual glands. The food thus becomes saturated in the mouth with two fluids, -mucus and saliva, both assisting in mastication and deglutition, the Jatter in addition acting upon the starchy constituents of the food. TEETH. Teeth are objects implanted in and protruding from the maxil- lary alveoli. They are characterised by the hardness and density of their specific tissues. Like bone, these tissues consist of earthy salts, with a basis of organic animal matter. They are harder than bone, which contains about 67, while teeth contain 76 i, 23er cent, of earthy salts. One material physical difference between a bone and a tooth is that the free portion of the latter bears exposure and friction with impunity, while the former can TEETH. ^ 289" endure neither without becoming diseased. Teeth vary with the class of animal in number, size, form, structure, position," and attachment, but in all cases they are in correlation with the food and generic habits of the animal. Thus, in herbivora, where grinding the food is necessary, the contacting surfaces of the molars are rough and flat. In carnivora, where tearing and crushing are requisite, the molars are sharp, pointed, and serrate ; in omnivora, where the food is general, the teeth are mixed in their character. The form of the teeth thus depends upon the natural food of the animal, and there is always a certain harmony between their disposition and the conformation of correlated organs. They are not found in all animals. Birds have none, while the typical number of mammalian teeth as viewed by Pro- fessor Owen is forty-four. Three hard structures enter into the formation of the teeth — Dentine, or Ivory ; Enamel ; and Cementum, or Crusta petrosa. DENTINE. Dentine constitutes the major part of the tooth, and is a hard, yellowish substance, consisting of very minute tubuli em- bedded in a dense, granular, intertubular matrix, which contains the bulk of the earthy matter, the latter being about thirty per cent, of the whole. The tubuli commence at the pulp cavity, and radiate to the superficies of the dentine, where they anastomose and their branches terminate in minute cavities, the dentinal cells, which perhaps are analogous to the lacunce of bone. The tubuli are about the of an inch in diameter, and. 40^00 in the fresh state, they contain processes Oblique section of dentine, show- ing the tubuli and coalescence of the calcified nodules. from the pulp. During the development of a tooth the calcification of the dentine proceeds from centres, around which tite calcific material becomes deposited. Thus nodules are formed, which, by expanding, finally coalesce and form the solid matrix. 290 SPLANCHNOLOGY. ENAMEL. In appearance enamel is distinguislied by its peculiar white- ness. It is the hardest animal texture, containing about 9G per cent, of earthy salts. It consists of hexagonal prisms, which are arranged side by side, with one extremity resting on the surface A of the dentine, whence they are disposed in gently wav- ing lines towards the surface of the tooth. They vary somewhat in diameter, but average ^^jj-q of an inch. No nutrient vessels ornerves have been traced into ena- mel, and when destroyed it is not reproduced. This tissue is protective, sometimes covering the entire exposed surface of the tooth, as in the human subject and the dog, and it also furnishes the rough projections and cutting edges found in the teeth of some classes of animals, the herbivora affording the best example of this. Fig. 94. A, Transverse section of enamel, showing the cut ends of its hexagonal prisms ; B, Prisms separated. CRUSTA PETROSA. Crusta Petrosa, or cementum, the third constituent, completely covers the imbedded portion of the tooth, and occupies the cavities on the free portion, where such exist. It is thickest towards the roots, most abundant on the molar teeth, and is distinguished by its brownish-yellow colour. It is the softest dental texture, closely resembling true bone in structure, having tubuli and cells resembling the canaliculi and lacunae, and where it is thick it may be traversed by vascular tubes analogous to the Haversian ■canals. The proportion of earthy matter, the same as in bone, is about 67 per cent. ARRANGEMENT AND KINDS OF TEETH. Teeth may be simple or compound. Simple as in the dog, ^here the entire exposed surface is covered by a solid cap of enamel, which alone is in wear ; compound or complex, as in the horse, where various tissues are in wear. A tooth consists of INCISOR TEETH. 291 1:he following anatomical parts ; the body, or crown, which is free of the gum, the grinding or cutting surface of which is the table ; the cervix, or neck, the part invested by the gum ; and the fang, or root, which is inserted into the socket or alveolus. The alveoli are more porous, spongy, and vascular than other bone ; they appear and grow with the teeth, and when these decay, become absorbed. They are lined by periosteum, which, reflected from the gum, at the base of the socket, covers the fang, communicating with the pulp cavity, which runs up the fang centre, and contains a highly vascular and nervous organ, the jjuljy, whence the dentine of the tooth grows. This pulp is enclosed in a vascular membrane, the dentine tubuli radiating from it. In the aged tooth this membrane becomes ossified, forming the secondary or osteo-derdine. The sensory nerve of the pulp comes from the fifth pair ; and it is owing to its extreme sensibility that toothache is so severe when tjie pulp is exposed. Teeth are arranged alongside of each other, so as to form the dental arches : these are interrupted at each side, leaving the interdental spaces, or diastemce. Teeth are of three kinds ; the Incisors, or cutting teeth, situated in front of the arches ; Canine teeth, or tushes, in the interdental spaces; and Molars, or grinders, behind. The horse, like many other animals, has two sets ; the temporary or milk teeth, and the permanent or horse teeth, the former numbering 24, the latter 40. In the mare there are usually. 36 permanent teeth, the tushes being wanting or rudi- mentary. INCISOR TEETH. The incisor or front teeth in the horse are 12 in number, 6 in each jaw ; the upper ones are the longer, their surfaces meet- ing those of the lower ones ; in rare cases the former overlap, constituting a " parrot mouth." The central pair are the largest, the adjacent ones are called the middle, or lateral, while the outer ones, which are the smallest, are termed the corner incisors. The row of incisors forms a curve, which is part of the so- called dental arch; the younger the tooth the greater the curvature, which gradually decreases with age. The anterior surface of a young incisor tooth presents a triangular shape, with the base at the table. Viewed laterally it is still triangular, but 292 SPLANCHNOLOGY. A Fig. 95. Incisor and canine teeth of a Horse. A, Front, B B, Lateral, and C C, Corner incisors; D J), Canine teeth. its apex is at the table. Tbe table is therefore oblong, its long axis following the line of the dental arch. As it wears, it narrows laterally, but its short axis widens, until in old age it is nearly round, what was the fang being in wear. The free surface of an incisor tooth, excepting the table, is covered by a layer of enamel ; the fang, which is a single process, being covered by crusta petrosa. Towards the centre of the table, in a young tooth, a second ring of enamel is visible, which is the mouth of a funnel- shaped cavity called the infundibulum. This cavity in the young animal is ovoid, its long axis following that of the table ; it is lined by crusta petrosa, which, be- coming stained by the food, constitutes, tbe so-called " mark." The space be- tween the two tubes of enamel is filled up with dentine ; hence the table is a comnound one — i.e., all three of the dental tissues are in wear on it The infundibulum, or mark, being conical in shape, wears with the tooth, becomes smaller, and ultimately vanishes. For example, the permanent central incisors are up at three years; in the lower jaw the infundibulum wears away about one-third in each year; the animal will probably, therefore, be six years of age when the mark is gone from the central incisors. Sometimes the cavity is absent, its place being occupied by crusta petrosa ; still, in the centre of the tooth there is the inner ring of enamel. Thus, in the transverse sec- tion of a young tooth, we notice an outer and an inner ring of enamel, the interspace being filled by a mass of dentine, and the inner ring lined by crusta petrosa (see Fig. 96). In the centre, the table in front of the infundibulum is broader than that behind it, and as the tooth wears it still broadens. In this space sometimes a spot is apparent which differs from the rest of the dentine ; it is the osteo-dentine covering the pulp cavity ; this. Fig Incisor tooth of a .Horse — posterior view. a, Outer layer of enamel; 6, Inner layer of enamel round the infundibulum; c, Dental star; d, The dentine. MOLAR TEETH. 293 object has been termed the dental star. The corner teeth may have no posterior tables, constituting shell teeth ; rarely they are absent in every tooth whea we have a shell mouth. The incisor rtiilk teeth are whiter than the permanent ones, and have distinct necks, the necks of the latter being imaginary. They are convex and grooved posteriorly, and have their dentine stained. Almost perpendicular to the axis of the head, in the young animal, the incisors become more and more horizontal as the animal ages. Permanent incisors are convex anteriorly, the lower incisors having one, the superior two grooves down the centre of the body ; these are filled with cementum, but are absent in old teeth. The incisor teeth attain their greatest development in the elephant, in which animal they project from the mouth as tusks, it may be to an enormous extent. CANINE TEETH. The tushes, tusks, or canine teeth, well developed in dogs and other carnivora, are simple teeth, four in number, a pair above and below. They rest in the interdental spaces, the lower being nearer the incisors than the upper ones ; they are permanent ab initio, and appear between the fourth and fifth year, sometimes a year in advance. The crown is somewhat conical, the base being at the gums. The external surface is convex, and marked by several fine longitudinal lines ; the internal surface presents on either side a sharp ridge which separates it from the external. The crown terminates in a conical eminence, somewhat hollowed internally during growth, and bounded by a sharp ridge. When a tusk has been long in wear, the ridge disappears, and the internal surface becomes nearly smooth ; and as the apex of the tooth becomes worn away, often a small mark appears, but no second ring of .enamel. These teeth have no constricted neck, and the fang is single. In the horse tribe, as a rule, canine teeth are developed only in the male ; if they exist in the female they are rudimentary. MOLAR TEETH. The Molars, or grinders, are 12 in the temporary set, 3 on either side of each jaw; 24 in the permanent set, 6 on each side above and below ; they are numbered from before backwards, and, like the incisors, those of the upper jaw are the larger. A molar tooth is constructed on the same general plan as an A Fia. 97. 294 SPLANCHNOLOGY. incisor, but the contour of the various parts is much more irregular. There are generally two infundibula containing a large quantity of cementum, a layer of which also covers the g^reater part of the external enamel. The crown of the upper molars is somewhat cubic ; their external surface presents two grooves running from table to root, the anterior being the deeper. The crown of the lower molars is narrower, but longer than that of the upper ones, and has only one groove. The inner surface of the upper molars is not so deep as the outer, while the inner surface of the lower ones is the deeper ; the two lower rows diverge towards the back of the mouth, while the two upper rows are rather convex Transverse 8ection"'of a molar tooth, externally. The molar grinding sur- A A, External crusta petrosa; B, Exter- face is Very irrcsfular, owinof to the nal enamel; C C, The dentine; D D, • -ii i i C • Internal enamel surrounding the infun. Variable hardueSS of itS COmponentS. Snf;nYbui'a™^'''^'""°"'^^^"' ^ horse may have supplementary molars, or wolf teeth ; these are small, and placed one on each side of the jaw, anterior to the first molars ; they are usually shed with the milk teeth. The teeth which replace the deciduous or milk molars are situated anteriorly, and are termed in general zootomy premolars. DENTAL FORMUL-E. A dental formula expresses in a concise manner the number and position of the teeth possessed by an animal. The numbers are written somewhat in the form of fractions, and prefixed are the initial letters of the names of the various teeth. Thus, i. stands for incisors, c. for canines, p.m. for premolars, and m, for molars. For example, the molar teeth of the dog are thus 2-2 represented : — m. o^^ ; this means that there are two molars on each side in the upper jaw, and three on each side in the lower jaw. In the ox the incisors are i. 5 — , or none whatever in the — upper, and three on each side in the lower jaw. The full dental formulae of the horse are as follows : — DEVELOPMENT OF THE TEETH. 295 Deciduous or milk teeth. . 3-3 0-0 3-3_12_ ^- 3^:3' ^' 0~0' '^' 3^~12"^*- Permanent teeth. .3-3 1-1. 3-3 3-3 20 ,^ *• 3~3' '• rri' V-^""- 3-:r3' ^^- 3-3 = 20=*^- DEVELOPMENT OF TH3 TEETH. The development of the teeth, as demonstrated by the late Professor Goodsir, consists of three distinct stages — papillary, follicular, and saccular. About the sixth week of foetal life a depress- sion is formed in the mucous membrane of the gum, which is the primitive dental groove, from the floor of which arise papillae or processes corresponding numerically to, and constituting the gerin^ of, the milk teeth ; this is the papillary stage. About the tenth week the groove deepens, the papillae enlarge, the margins of the grooves thicken and become prominent ; prolongations or septa pass from one side of the groove to the other, enclosing each papilla in an open follicle or sac ; this constitutes the follicular stage ; it terminates about the fourteenth week. Somewhat later, the papillae begin to assume the shape of the crowns of the future teeth. Small membranous processes or opercula are now developed firom the sides of the follicle, which correspond in number and shape with the table surfaces of the teeth ; thus, for the incisors, there is one on either side, the tushes have three, and the molars four or five, according to their size and situation. The lips of the follicles, as well as the opercula, close and cohere, and the grooves becoming obliterated, what were open follicles are con- verted into closed sacs, thus completing the saccular stage. Shortly before the closing of the follicles of the milk teeth, a lunated depression is noticed behind, and to the inner aspect of each follicle ; these become converted into cavities of reserve, which ultimately form sacs for the development of the permanent incisors, as well as the three anterior permanent molars. The dental sac, as well as the enclosed papilla, continues to enlarge, the papilla becoming converted into the pulp, and acquiring the semblance of the dental crown. The contents of the sac now consist of the vascular pulp, covered by its membrane — an internal vascular layer, lining the sac, called the periodontal membrane ; and a fluid lying between the two membranes, the outer or 296 SPLANCHNOLOGY. enamel pulp. The process of calcification now commences. A. thin lamina or cap of dentine is first developed on the outer and most prominent part of the pulp, from its covering membrane ; this continues to be formed by the substance of the pulp, which gradually decreases as the dentine increases, the enamel being, at the same time, deposited in crystals from its own peculiar or outer pulp. The cementum also forms pari passu, from the calcification of the periodontal membrane lining the sac. When calcification of the dental textures is sufficiently advanced, the tooth makes its way through the gum, which is absorbed, as the crowns are forced upwards by the growth of their fangs. The septa or divisions between the dental sacs now ossify, and con- stitute the alveoli. As growth continues, the base of the pulp contracts and forms the neck. The dental sac now elongates, and gradually becomes less, owing to the formation of dehtine on its outer surface, until only a small cavity is left in the centre, in which rests the pulp and its vessels. In the molars, every point on the crown has a separate cap of calcification. These enlarge, and finally meet. In the formation of the molar fangs the pulp divides, ossification in each section proceeding as in a singie-fanged tooth. The permanent teeth are developed like the temporary ones. As the permanent tooth continues to grow, it gradually presses on the milk tooth, and ensures absorption of its roots, until the entire fang becoming removed, the crown of the milk tooth falls out, and the permanent tooth appears above the gum. The remaining permanent teeth, the three posterior molars in each side of either jaw, are developed thus : — Behind the third molars there is a portion of the dental groove unobliterated, which forms a cavity,- called the posterior cavity of reserve, in which a papilla appears, and undergoes the same change as that of the temporary teeth, forming the rudiment of the fourth molar. From this cavity is developed a second follicle for the fifth, and from this the follicle of the sixth or last molar. PHAEYNX. The pharynx is a musculo-membranous cavity common to 'the digestive and respiratory canals. Somewhat cylindrical in the horse, it extends obliquely downwards and backwards, and lies behind the velum palati, which separates it from the mouth, an4. forms its anterior wall. It is attached superiorly to the base of PHARYNGEAL MUSCLES. 297 the cranium by muscles and aponeurosis, infero-laterally to the Jaiynx, and infero- posteriorly it is continuous with the oesophagus. It communicates with other cavities by seven openings — viz., the %^o posterior nares superiorly ; posteriorly, on either side, with the slit-like openings of the Eustachian tubes, which lead to the guttural pouches, and are guarded by a cartilaginous valve ; anteriorly, below the posterior nares, is the isthmus of the fauces, leading into the mouth, and, excepting during deglutition, closed by the velum palati ; inferiorly, behind the root of the tongue, is the opening of the larynx, and behind this tbe oesophagus. The walls of the pharynx consist of a muscular layer, with a lining of mucous membrane. PHARYNGEAL MUSCLES. The muscular layer of the pharynx is separable into seven pairs of muscles. These are best seen posteriorly, where they appear as a series of flattened, fleshy bands, the superior of which meet their fellows of the opposite side at a mesian vertical line or raphe. The names of the muscles are as follows, and, excepting the first a,nd last, they are named in order from above downwards : — Pharyngo-staphylinus. Pterygo-pharyngeus. Kerato-pharyngeus. Hy o-phary ngeu s. Thyro-pharyngeus. Crico-pharyngeus. Aryteno-pharyngeus. PHARYNGO-STAPHYLINUS. (See Muscles of the soft palate.) PTERYGO-PHARYNGEUS. (Fig. 90. I.) This is a thin, broad band of muscle arising- from the pterygoid process. Its fibres are directed backwards and downwards. It terminates by meeting its fellow at the posterior median line of the pharynx, of which cavity it is a constrictor. KERATO-PHARYNGEUS. (Fig. 90. m.) Arising from the inner aspect of the hyoid comu, this muscle, A small, narrow band, runs inwards and downwards to the wall of the pharynx, becoming blended with the pterygo-pharyngeus. It is a levator, and by some considered a dilator of the pharynx. 298 SPLANCHNOLOGY. HYO-PHARYNGEUS. (Fig. 90. n.) This is a flat muscle arising from the heel process of the hyoicJ bone, and slightly from the thyoid cartilage of the larynx. Its fibres passing upwards and backwards, it reaches its fellow of the opposite side at the posterior median line. It is a constrictor. THYEO-PHARYNGEUS. (Fig. 90. o.) Placed immediately below the muscle last described, this- muscle joins its fellow in a similar manner, arising from the- thyroid cartilage. It also is a constrictor. CRICO-PHARYNGEUS. (Fig. 90. p.) Situated below the thyro-pharyngeus, this muscle arises from the lateral aspect of the cricoid cartilage. Its fibres run back- wards, converging slightly upwards, and it terminates similarly- to the two muscles last described, its action resembling theirs. ARYTENO-PHARYNGEUS. This is a small band stretching from the posterior aspect of the arytenoid cartilage to the muscular wall of the cesophagus,^ its action being to raise the latter. The pharynx is supplied with blood by the pharyngeal and thyro-laryngeal arteries. Its nerves are derived from the ninth and tenth pairs, and from the sympathetic. Its respiratory function is purely a passive one, while what may be termed its alimentary function is an active one, to assist in deglutition. (ESOPHAGUS. The oesophagus, or gullet, is a long musculo-membranous cylindrical canal, passing from the pharynx to the stgmach, through which the food reaches the latter. Originating at the lower part of the pharynx, immediately behind the aperture of the birynx, it descends the neck, at first behind the trachea, then inclines to the left of it, the two entering the thorax together; it (ESOPHAGUS. 29i) then passes lo the tipper side of the trachea, over the base of the heart, through the posterior mediastinum, and through the diaphragm by the foramen sinistrum ; it thus gains the abdom- inal cavity, and terminates in the cardiac orifice of the stomach. It is narrowest at its origin behind the larynx, then of uniform size until it reaches the diaphragm", where it again constricts. The oesophagus may be said to consist of a cervical, a thoracic, and an abdominal portion, the latter being very short. It con- sists of two tunics, an internal mucous and an external muscular, which are very loosely united by areolar tissue. The mucous coat is continuous with that of the pharynx and stomach, but is pale in colour, and clothed with dense stratified epithelium ; it presents numerous longitudinal folds, which allow of considerable dilatation, and a number of racemose glands. The muscular coat consists of an external longitudinal, and an internal circular layer of fibres. The cervical and anterior thoracic muscular coat h striated, the remainder non-striated, but both are involuntary. The longitudinal layer commences by three fasciculi, one in front and one on either side, which unite to form a continuous layer. The circular fibres originate at the inferior constrictors of the pharynx. Posteriorly, both sets of fibres pass to the muscular coats of the stomach. The oesophagus is supplied with blood anteriorly by twigs from the carotid, and the broncho-cesophageal arteries posteriorly ; its nerves come from the pneumogastric. The oesophagus has no other use than for the conveyance of aliment from the pharynx to the stomach. Its most noteworthy features in the horse are, — first, the abrupt manner in which it enters the stomach, hardly dilating at all before doing so ; secondly, the enormous proportionate size of its mucous membrane posteriorly; this is so large, that near the stomach its folds completely fill the tube when empty, thus acting as a valve, and preventing regurgitation of the food. The process of deglutition, or swallowing the food, is performed in the following manner : — The masticated food gathers as a bolus at the root of the tongue, which by retracting forces the pellet through the isthmus faucium into the pharynx ; the velum pendulum palati recedes backwards and upwards, while the food forces down the epiglottis, effectually closing the larynx ; finally, the pharynx, by its constrictor muscles, grasps the bolus, and presses it downwards into the oesophagus. , The passage of food 300 SPLANCHNOLOGY. into the pharynx is purely voluntary ; but as soon as it enters the oesophagus, the act of deglutition is entirely involuntary, the food travelling by a vermicular or peristaltic motion, caused by the circular muscular fibres of the oesophagus contracting with successive regularity. ABDOMEN. The ultimate organs of digestion are contained in the abdomen, or belly, which is a large and somewhat ovoid cavity, bounded superiorly by the muscles of the sublumbar region; inferiorly and laterally by the abdominal muscles ; and anteriorly by the dia- phragm ; posteriorly it is continuous with the pelvic cavity. It contains chiefly the stomach, intestines, and kidneys, with their uccei^sories. It is lined by the peritoneum, a serous membrane, which is reflected over the viscera. For convenience of description, the abdomen is divided into nine regions, indicated by imaginary lines drawn as follows : — ■ Two transverse lines divide it into three primary regions. The first line is drawn from the cartilage of the last false rib on one side, to that of the other ; the second unites the right and left anterior iliac spines. These divide the cavity into the anterior or epigastric, middle or umbilical, and posterior or hypogastric regions. These regions are each subdivided into three secondary, or right, left, and central regions, by two longitudinal lines, extending from either side of the ensiform cartilage to about the ilio-pectineal eminences, completing the division, which may be tabulated as follows : — Eight. Centbal, Left. Anterior. Middle. Posterior. Right Hypochon- driac. Right Lumbar. Right iliac. Epigastric. Umbilical. Hypogastric. Left hypochon- driac. Left lumoar. Left iliac. The portion of the alimentary canal contained in the abdomen comprises the stomach and intestines. STOMACH. 301 STOMACH. The stomach is a dilatation of the alimentary canal, continuous ■with the oesophagus and small intestine, where the food is con- verted into chyme, by maceration and the action of the gastric juice. In the horse it is small in proportion to the size of the animal, and rests in the left hypochondriac region, stretching when full into the epigastric ; when distended, it resembles a bent tube with two lateral dilatations, divided by a central constriction into a left, or cardiac, and a right, or pyloric portion. The former is Fio. 98. Posterior view of the stomach of a Horse, a, Left eul-de-nac; b. Right eul-de-sac; e. Greater curvature ; d. Lesser curvature ; e, (Esophagus; /, Duodenum. the larger, and called the greater cul-de-sac, or fundus; the right portion, is the lesser cul-de-sac, or antrum pylori. It has one opening on the left, leading into the oesophagus, through which the food enters ; this is the cardiac orifice ; and another on the right, which communicates with the first portion of the intestine called the duodenum ; this is the pyloric orifice. At the pyloric orifice there is a constriction called the pyloric ring. Between the two openings the upper and lower borders are termed the •curvatures, the superior or lesser being concave, the inferior or greater convex. The curvatures indicate the division of the surface of the stomach into two portions, an anterior and posterior. The S02 SPLANCHNOLOGY. anterior is related with tlie diaphragm and liver, the posterior with- the diaphragmatic flexure of the colon. The spleen lies along; the inferior and external part of the greater cul-de-sac, its base being directed backwards and somewhat upwards ; the pyloric extremity, which is placed lower than the cardiac, is related with the right lobe of the liver and the intestines. The walls of the stomach are composed of three coats — an external serous, a middle muscular, and an internal mucous coat. The serous coat, a reflection of the peritoneum, is smooth and elastic, adhering intimately to the muscular, except at the lesser curvature, where, strengthened by addition of yellow elastic tissue, it forms a ligament, which appears to support the two extremities of the stomach ; forming around the cardiac orifice a circular fold, which surrounds the oesophagus and passes to the dia- phragm ; this is the gastro-phrenic, or coronary ligament The peritoneum also passes in a double fold from the greater curvature to the spleen, as the gastro-splenic, to the colon as the gastro-colic, or great omentum ; and from the lesser curvature to the liver, as the gastro-hepatio omentum. In the m,uscular coat are three sets of fibres — an external longitudinal, a middle circular, and an internal oblique layer. The longitudinal are continuous with those of the oesophagus, and radiate from the cardiac orifice ; they are thickest at the curvatures, and are thinly scattered over the surfaces ; towards the pyloric end they again converge, and form a uniform layer^ which is continuous with that of the duodenum. The middle layer consists of circular fibres, which cover the entire organ ; near the pylorus they thicken into a circular ring, which projects into the orifice, and forms with a doubling of the mucous mem- brane, a sphincter, called the pyloric valve, which by contraction prevents crude food from passing into the intestine. The inner layer, is composed of oblique fibres, continuous with the circular oesophageal ones ; they are confined to the cardiac portion, descend obliquely over either surface, and disappear towards the central constriction. All these layers are composed of pale or involuntary tissue; the longitudinal layer, by contracting, enables the stomach to dilate ; the circular produces vermicular motion, while the oblique layer tends to force the food from the left into the right cavity ; thus there is produced a kind of churning motion, which macerates the food and brings each portion of it- into contact with ths mucous surface. STOMACH. 303^ The internal, or mucous coat, is divided into right and left portions. The latter is the cuticular portion, continuous with the mucous membrane of the oesophagus, which it resembles in structure and appearance; it is covered by a thick layer of stratified epithelium. The line of demarcation between the two portions is abrupt and dentated. The right portion, the villous,. or true digestive coat, is reddish in colour, soft, very vascular, and velvety-looking. When examined with a lens, it appears honey-combed, or covered by small shallow polygonal depressions or alveoli, separated from each other by projecting intervals. Internal aspect of Horse's stomach, opened from below, a a, Cuticular mucous membrane ; i 6, Villous mucous membrane ; c c c, Line of demarcation between the two portions ; d, Cardiac orifice ; e. Pyloric orifice and valve. Into these alveoli the gastric follicles open ; the latter lie in the subepithelial tissue, perpendicular to the surface of the mem- brane ; at the pyloric end some of these folliqles terminate in dilated sacs, or divide into two or more tubes. They consist of a basement membrane, lined by columnar epithelium ; some of them secrete gastric juice, others mucus ; the latter are lined throughout with epithelium, while the gastric juice follicles have their lower part filled with nucleated cells and granules. The villous coat is also covered with numerous simple or lenticular follicles. The mucous membrane, when the organ is empty, is thrown into folds, or rugce, which are very well seen in the villous por- 304 SPLANCHNOLOGY, tion, where they do not entirely disappear on inflation. The cardiac orifice is closed by the mucous membrane of the 03S0- phagus ; its numerous folds completely filling that tube at its termination when empty ; the valve thus formed is air-tight. The arteries of the stomach arise from all the branches of the coeliac axis ; they are the gastric, the left gastro- epiploic from the splenic, and the right gastro-epiploic from the hepatic ; the "blood is returned by satellite veins which join the vena porta. The nerves are from the pneumogastric, and solar plexus of the sympathetic. The use of the stomach is to macerate the food by the action of its muscular walls, and also to saturate it with mucus and gastric juice, the latter containing a principle called pepsine, which acts chemically on albuminous mattcis. The entire operation is called cliymification, and the food thus prepared the chyme. THE INTESTINES. These are divided into the large and small ; the two however form a continuous musculo-membranous tube, the small intestine being likewise continuous with the stomach at. its pyloric orifice. These organs are tortuous in their course, and in herbivorous animals are long and capacious. SMALL INTESTINE. The small intestine commences at the pylorus, and terminates, in the caecum. It consists of a cylindrical convoluted tube, rather more than an inch in diameter, and about seventy-two feet in length. It presents two curvatures-, the greater one, convex and free, the lesser concave and attached to the mesentery, by which it is suspended from the roof of the abdomen, occupying the central region, and partly surrounded by the large intestine. It is arbitrarily divided into the Duodenum, the Jejunum, and the Ileum. The duodenum, continuous with the pylorus, is the only fixed portion of the small intestine. In the horse it is short, present- ing a dilatation at its origin resembling a miniature stomach, with its curvatures disposed inversely to those of the stomach itself. On leaving the pylorus it runs forwards, then backwards, forming an abrupt curve. It now crosses from right to left, and SMALL INTESTINE. 305 becomes the jejunum at the level of the anterior mesenteric artery. The first portion is more free than the latter. At from four to five inches from the pylorus is the opening by which the ducts of the liver and the pancreas enter the intestine. The. jejunum succeeds the duodenum, and includes about two-fifths of the remainder of the small intestine, the ileum constituting the rest ; both are floating — i.e., they are attached to the free edge of the mesentery. The ileum terminates, in the right iliac region, in the large intestine. Fio 100. The two mesenteries ; the great colon being removed, a, Anterior mesentery ; h h. Mesenteric glands; c c c, Loops of the small intestine ; d. Colic mesentery ; e e c. Loops of the floating colon : /, Sphincter ani— internal layer ; g, Levator ani. The walls of the small intestine, in common with all- hollow viscera of the abdomen, consist of an external serous, a middle muscular, and an internal mucous coat. The two latter are joined by areolar tissue, which is sometimes regarded as a submucous coat. The serous coat envelops the intestine, except- ing just at its attached border, where the two folds join and form the mesentery. The muscular coat consists of two layers of fibres, an outer longitudinal, which is very thin, especially at the attached border, and an inner circular one, which is thicker ; both are pale, and involuntary. The mucous coat is soft, spongy, reddish, and vascular, covered X 306 SPLANCHNOLOGY. by nuQierous minute villi and follicular openings, the whole being clothed by columnar epithelium. It is thrown into folds when empty, which usually disappear when it is dilated ; these .are known as valvulce conniventes. INTESTINAL GLANDS. The mucous membrane of the small intestine is furnished with glands and absorbents. Besides the mucous follicles, we note the following glands : — Glands of Brunner. I Payer's patches. Crypts of Lieberkiihn. j Solitary glands. The glands of Brunner, which are small glands, resembling the acini of the salivary glands, are found in the duodenum. The crypts, or follicles of Lieberkuhn, are very small, and are found throughout the intestines, between the villi and around the larger glands. The glands or patches of Ftyer, are oval or circular groups of solitary glands, forming agminated glands, and are found in the jejunum and ileum ; they are mOst numerous near the termination of the ileum. Each gland is a simple vesi- cular ductless sac, containing a lym- phoid material. Single sacs, similar to those forming Peyer's patches, called solitary glands, are scattered throughout the intestines, and sur- rounded by LieberkUhn's crypts, which form round each gland a ring known as the corona tubulorum. The absorbents originate in the villi, which are small, finger-like, vascular processes, thickly distri- buted over the mucous surface ; they consist of loops of the lacteal or chyle vessels, surrounded by a net-work of capillaries, fine muscular fibres, and small gran- ular corpuscles, with a mucous layer covered by columnar epithelium. The small intestines are supplied with blood by the anterior mesenteric and duodenal branch of the hepatic arteries, the blood being returned by the satellite veins to ITlo. 101. "Section of mucous membrane of the small Intestine. Ou the left a villus is seen in section, a, The epithelial covering ; c, The blood-vessels ; d, The basement membrane, or subepithelial layer ; e, Spaces for re- ception of the chyle ;/, Origin of a lacteal vessel. On the right is a follicular depres- sion in the mucous membrane, with b. The cells lining it ; and c. The subepithelial layer. c^cuM. 307 the portal system. The lymphatic vessels of the small intes- tine are distinctively known as the lacteal vessels, and they convey away the chyle absorbed by the medium of the villi. The nerves are from the solar plexus. The vessels and nerves gain or leave the small intestine by passing between the two folds of peritoneum which form the mesentery. In the duodenum the chyme becomes saturated with the bile and pancreatic juice, the change thus induced being termed chylification or conversion of the chyme into chyle. In the rest of the intestine we note the absorption of the chyle by the lacteals, the final preparation of the food by the various gland secretions, and the reabsorption of the bile by the blood-vessels. Chyle is a milky-looking fluid, its turbidity being due to the presence of an immense number of minute granules. It contains also the chyle Fia. 102. A, Microscopic appearance of a drop of chyle from the thoracic duct ; a, Granular base ; 6, Fatty particles ; e. Chyle corpuscles ; B, Isolated corpuscles showing the cell- membrane in its developing stages, abed. corpuscles, which are nucleated sacs resembling those of the lymph, or the colourless corpuscles of the blood. LARGE INTESTINE. The large intestine extends from the termination of the ileum to the anus, and may be regarded as consisting of four parts, which will be described in order: the Caecum, the Great colon, the Floating colon, and the Rectum. C^CUM. The caecum, blind intestine, or caput ccecum coli, is a large cul-de-sac, commencing in the right iliac region, passing obliquely downwards and forwards, and terminating in the left hypochon- driac region by a pointed, blind extremity ; thus it crosses 308 SPLANCHNOLOGY. obliquely the middle line of the abdominal floor. It measures- about thirty-six inches in length, and its capacity may average six gallons. It is somewhat conical in shape, and curved at its supero- posterior extremity, presenting on its outer surface a number of circular constrictions, and certain longitudinal muscular bands, of which there are four about the middle. The superior extremity is called the base or arch, and presents a convex curvature directed backward, and a concave one forwards. In the concave curvature the ileum terminates, and there also the large colon originates. The middle part of the caecum is related with the small intes- tines, the apex being free, and prolonged to the sternum. It is fixed to the abdominal wall posteriorly by cellular tissue, and to the origin of the colon by a double fold of peritoneum, called the meso-caecum. The interior of the caecum presents a number of transverse ridges, corresponding to the external transverse constrictions. Two orifices, placed one above the other, are found in its concave curvature; the inferior one marks the termination of the ileum, and is guarded by the ileo-coecal valve, which is formed by a doubling of the mucous membrane, within which is a band of muscular fibres. The superior opening communicates with the colon. The caecum has three coats, serous, muscular, and mucous, the latter being thicker than that of the small intestines, and having neither Brunner's glands nor Peyer's patches. The folli- cles of Lieberkiihn, solitary glands, and a few scattered villi are however present. GREAT COLON. The great or double colon originates from the caecum, and ter- minates near its origin in an abrupt contraction, whence arises the floating colon. Taken out of the abdomen, it appears as a voluminous tube, with successive dilated and constricted portions; like the caecum, it is marked throughout by longitudinal bands and transverse furrows. It measures, on an average, from nine to eleven feet in length, and sometimes has the capacity of eighteen gallons. It is doubled on itself, forming two branches of equal length, placed one on the other, and so disposed that the terminal end is near the origin. When in situ, the doubled portion forms a curve whose convexity is directed forwards, and corre- sponds to the walls of the abdomen, thus forming four divisions, a right and left being above, and a right and left below, with GREAT COLON. 30& three Jiexiiycs or oends. la tracing its course, these tour divisions present themsshes thus. Leaving the arch of the caecuna in the right lumbar region, it passes obliquely forwards to the posterior surface of the diaphragm in the epigastric region, where it turns round to the left, forming the first or sternal flexure. Here the second division originates, and in contact with the inferior ab- f IG. 103. i,^.Csecum ; h, CiEcura and Great Colon of a Horse. a,!.Caecum ; &, c, Its muscular bands ; d. Termination of the ileum; e. First, c', Second, /, Third, and /', Fourth division of colon ; g, Pelvic flexure ; h, Ongln of Floating Colon. The arrows indicate the course of the food through the colon. glandular pouches, where is secreted a strong foetid matter. Accessory Organs of Digestion. Tlie liver is large, and deeply cleft into five lobes, a gall bladder being lodged in the middle lobe. The biliary duct unites with a small duct from the pancreas before entering the duodenum. The pancreas is elongated, running along the concave curvature of tbe dxio- denum ; its anterior end reaches the lesser curvature of the stomach. There are two ducts, a large one entering the duodenum alone, and a smaller, wbich. joins the bile duct. The spleen is long and irregularly club-shaped. Tt is suspended in the great om>entum, near the left sac of the stomach. Its thick, blunt extremity is. placed anteriorly. Fig. 146. Stomach, Liver, Pancreas, and Duodenum of a Dog. a a, Liver ; b, Gall-bladder ; c c, Biliary Canals ; d. Cystic Duct ; e, Ductus Chole- docus ; /, Pancreas ; g, Pancreatic Ducts. RESPIR.^TORY SYSTEM. The septum nasi is prolonged on either side, thus taking the place of the alar cartilages, and being continuous with the cartilaginous prolongations of the inferior turbinals. There is only One maxillary sinus on each side. The thoracic cavity is usually very large in carnivora. The lungs are divided, the left into three, the right into four lobes, by clefts which reach almost to the root of the organ. The heart is completely surrounded by the lungs, not embedded in depressions in them. The pulmonary tissue is very compact, the lobules being small, while the air-cells are well developed. URINARY AND GENITAL SYSTEMS, The kidney is ovoid, but shorter than in the hog ; in the cat it is still shorter, being almost round. The pelvis is simple, presenting a single large elongated papilla. The bladder is furnished with a very strong muscular coat. RODENTIA. 383" The testicles are situated in the perineal region, below the anus. The vesicul . , , . , _, , > Abdommal. Renal. Spermatic. Small testicular. The BrOnchO- (ESOPHAGEAL arises close to and sometimes with' the first pair of aortic intercostals, breaking up into bronchial and oesophageal branches. The bronchial arteries pass between the aortic arch and the oesophagus, to the bifurcation of the trachea, dividing into right and left, which enter the lungs with the bronchi, ramifying with the air-tubes, and terminating in the pulmonary capillaries. The oesophageal artery proceeds back- wards to the posterior mediastinum ; reaching the oesophagus, it divides into two. The large superior one is distributed to the upper, the inferior to the linder surface, ^nastomosii^g Avith the pleural branch of tbe gastric, and supplying the posterior mediastinum. CCELIAC AXIS. (Fig. 155. 1.) This is a short trunk arising from the lower surface of the aorta as it enters the abdomen. About an inch in length, it divides into the gastric, splenic, and hepatic arteries. The Gastric, the central and smallest division, passes the cardiac orifice of the stomach, and divides into right or anterior, left or posterior, and pleural ; the latter enters the thorax by the foramen siuistrum, bifurcates and anastomoses with the oesophageal and superior branches of the thoracic artery. The right gastric passes to the oesophagus over the lesser curvature of the stomach. CCELIAC AXIS. 405 and is distributed to the anterior aspect of the greater cul-de-sac ; the left gastric gains the posterior aspect, and ramifies over the right cul-de-sac ; both are tortuous, and anastomose with each other and with the splenic artery. The Splenic artery, the largest coeliac division, passes to the left, over the fundus of the stomach, and enters the hilus of the Abdominal branches of the posterior aorta- .^the left abdominal wall and diaphragm, small intes- tine and great colon being removed. I, Aorta ; II, Liver ; III, Stofnach ; IV, Spleen ; V, Left kidney; VI, Floating colon: 1, Coeliac axis; a, Gastric artery; a'. Its anterior, and o". Its posterior branch; a'", Pleural artery; 6 h, Hepatic artery ;. 6' 6', Pyloric artery; 6", Duodenal artery ; 6"', Right gastro-epiploic artery ; c, Splenic artery ; d. Pancreatic branch ; c" c", Small branches to the stomach ; c'", Left gastro-epiploic artery ; 2, Anterior mesenteric artery divided ; 3, Left renal artery ; 4, Left spermatic artery divided ; 5, Posterior mesenteric artery ; d d. Its radiating branches ; d' d' d'. Their inosculatory arches ; d", Hasmorrhoidal branch ; 6 6, Lumbar arteries ; e e, Their spinal branches. spleen, enveloped in the gastro-splenic omentum ; at the splenic apex it becomes the left gastro-epiploic, which passes along the greater curvature of the stomach as far as the lesser cul-de-sac, finally anastomosing with the right gastro-epiploic branch of the hepatic artery ; it supplies the spleen and stomach, and gives a small twig to the pancreas. The Hepatic artery passes to the right, partly embedded in 406 ANGIOLOGY. the pancreas, crosses obliquely under the posterior vena cava, and entering the trans- verse fissure of the liver, is distributed to that organ, along with the vena porta; it supplies the substance of the liver, in which organ its ulti- mate branches form three communicating series, to which the following terms have been applied : the rami vasculares, which supply the walls of the bile ducts and blood ves- sels, as vasa vasorum ; the rami capsulares, which supply the capsule; and the rami lohulares supplying the substance of the lobules. The hepatic artery gives off 'pancreatic twigs to the pancreas, and i\Le pyloric, which passes over the duodenum to the pylorus and lesser curvature of the stomach, anastomos- ing with the left gastric. The hepatic artery also gives off the right gastro- epiploic and duodenal. The former, crosses the duodenum, gains the greater curvature of the stomach, and inosculates with the left gastro- epiploic ; the latter pro- ceeds along the curvature of the duodenum, and anastomoses with a branch of the great mesenteric artery. Fig. 156. Arteries of the ceecum, colon, and part of the floating colon. I, Trunk of the great mesenteric artery • a, Anas- tomotic artery of the floating colon ; 6 b 6, Left colic artery ; V, Pancreatic branch ; cec. Right colic artery ; d, Inosculation of the two colic arteries ; «, Ileo-csecal artery. LESSER MESENTERIC ARTERY. 407 GREAT MESENTERIC ARTERY. (Fjg. 155, 2.) The anterior or great mesenteric artery arises a little behind the coeliac axis, and splits into left, right, and anterior divisions. The left consists of a score or so of branch lets, which pass to the mesentery, being arranged in a radiating -manner between its folds, and inosculating with each other near the lesser curvature of the small intestine, so forming arches, from which twigs proceed to the intestine. The first of these branches anastomoses with the duodenal branch of the hepatic. The right division divides into ileo-csecal, superior and inferior csecal, and right colic arteries. The ileo-ccBcal passes in the mesentery along the ileum, and inosculates with the last branch of the left division. The superior or internal ccecal goes to the upper, the inferior or external coical to the lower fissure of the caecum ; as it crosses the junction of the colon and csecum, it supplies the artery of the arch which winds partly round the origin of the colon. The right colic supplies the first and second portions of the large colon, inosculating with the left colic at the pelvic flexure. The anterior division consists of the left colic or retrograde, and a branch to the floating or single colon ; near its origin it gives off a branch to the pancreas. The retrograde runs parallel with the right colic, inosculating with it, and supplying the third and fourth portions of the great colon. The artery of the floating colon anastomoses with the posterior mesenteric artery. LESSER MESENTERIC ARTERY. (Fig. 155. 5.) The posterior or lesser mesenteric artery originates at from three to four inches behind the great mesenteric ; longer but less capacious than the latter, it divides into thirteen or fourteen branches, which supply the floating colon and rectum, one branch anastomosing with the artery of the floating colon from the anterior mesenteric. They lie in the folds of the colic mesentery, and the first eight form arches as in the anterior mesentery, but the rest, which chiefly supply the rectum, break up singly without forming arches ; these are known as the hcemorrhoidal arteries. 408 AlsGIOLOGY. The Renal arteries, right and left, leave the aorta at right angles, almost corresponding with the anterior mesenteric artery ; the right, having to cross the vena cava, is the longer. They pass straight to the hilus of the kidney. Reaching the limiting layer, they break up and form the capillary network, and Malpighian i-io. 157. Breaking up of the posterior aorta— the pelvis being opened on the left side. 1, Spermatic cord divided ; 2, Septum scroti ; 3, Penis ; 4, Bladder ; 5, Left Tesicula seminalis ; 0, Rectum. Ar.TEBiEs— A, Posterior aorta ; a. Spermatic ; h, Kxternal iliac ; h', Circumflex ilii ; h" h'" , Branches to iliac glands ; h"". Small testicular; c, Prepubian ; c', Epigastric; c" , External pubic; B B, Internal iliacs ; d, Left ilio-lumbar ; e, Common Origin of umbilical and Internal pudio ; e', tTmbilical ; e". Internal pudic ; /, Lateral sacral; g, Right Ilio-lumbar ; h. Gluteal ; i, Iliaco-femoral ; k. Obturator. tufts (see Kidney). An anterior branch supplies the suprarenal capsule. The Spermatic arteries, right and left, become, in the female, the utero-ovarian. They spring from the under surface of the posterior aorta, near the posterior mesenteric, it may be behiod. INTERNAL ILIAC ARTERY. 40 & on a level with, or before it, and they may both arise in common. The spermatic, their diameter considered, are the longest arteries in the body ; they pursue a diverging course through the inguinal canal, and become a constituent of the spermatic cord, lying on its anterior border ; as they near tlie testicle they become extremely tortuous, and are finally distributed to the tunica vasculosa. The Utero-ovarian artery passes to the broad ligament of the uterus, dividing into ovarian and uterine branches. The former is tortuous, supplying the ovary ; the latter passes to the cornu of the uterus, anastomosing with the uterine artery. The Small testicular, or Artery of the cord, is small, and sometimes arises from the aorta, between the internal and external iliac arteries, or it may arise from the latter, far down. It passes through the inguinal canal, and supplies the tissues of the cord, first giving twigs to the ureter, vas deferens, and peri- toneum. In the female, this artery becomes the Uterine, which is much larger, and is distributed to the body and cornu of the uterus, anastomosing with the utero-ovariaa and vaginal arteries. The posterior aorta at the level of the last lumbar vertebra gives off the External Iliac arteries, and a little po.sterior to this the rest of its trunk bifurcates, forming the Internal Iliac arteries. These four vessels are all large, and their origins are so near together that the breaking "dp of the aorta has been termed the iliac quadrifurcation. INTFiM'TAL ILIAC ARTERY.- (Fig. 157. B B. ; Fig. 158. C C.) The internal iKac arteries are short, thick trunks, extending from the last lumbar vertebra to near the insertion of the psoas parvus. They supply the pelvic viscera,- and partially the muscles of the Lind quarter. Each of these trunks gives off the following arteries : — Umbilical. Iliaco-femoral. Internal pudic. Obturator. Ilio-lumbar. Gluteal. Lateral sacral. The Umbilical artery, large in the foetus, is a mere fibrous 410 ANGIOLOGY. cord in the adult ; it extends from the aorta to the fundus of the bladder, inside the free border of the lateral false ligament, winding partly round the vas deferens. The Internal pudic, or Artery of the Bulb, passes back- wards and downwards, related with the supero-lateral aspect of the bladder ; it winds over the ischial arch, supplying the bulb and crura of the penis. It gives off posteriorly several twigs to Fig. 153. Distribution of the internal iliac[aTteri%s— ihe pelvis opened from the right side and the viscera removed. I, The tail ; II, The penis ; A, Posterior aorta ; B B, External iliacs ; C C, Internal iliacs •, C Middle sacral ; 1 1, Last lumbars ; C 2, Internal pudics cut ; 3 3, Lateral sacrals ; a a, Sicto-spiuals ; 6 6, Iliddlo coccvgeal ; c c, Lateral coccygeals; d, Superior branch of same, e e, Ischiaticj ; i, Ilio-lumbiW ; 5, Gluteal; 6, lliaco-feraoral ; /, Nutrient artery of ilium; 7, Obturator; g, Katrien'.. artery of ischium ; h, Inferior branch ; i, Cavernous and crural portion. Cowper's gland, and anteriorly the vesico-prosictic artery, which gives a posterior branch to the prostate gland, an anterior one to the vas deferens, and also twigs to the buJb of the latter, to the vesicula seminalis, and walls of the bladder ; one branch is the perineal artery which passes the ischial arch, and supplies the anus and urethral muscle superiorly. In the female the internal EXTERNAL ILIAC ARTERIES. 411 pudic artery furnishes branches to the rectum, vulva, and vaginal bulb, together with the analogue of the vesico-prostatic in the male — the vaginal artery, which anastomoses with the uterine, supplying also the bladder. The perineal artery in the female supplies the vulva. The Ilio-lumbar artery is given off at a right angle, passing between the iliacus muscle and the venter surface of the ilium. It supplies the sacro-iliac articulation, the sublumbar muscles, and surmounting the iliac crest, becomes buried in the gluteus maximus. The Iliaco-femoral artery, large in the horse, passes down- wards and outwards, crossing the iliacus, ,to supply the crural triceps and tensor fasciae latse from the outside. The Obturator artery is sometimes regarded as having a common origin with the iliaco-femoral, sometimes, and more correctly as being given off by the latter. It is a long vessel passing backv-;ards and downwards, along the lower edge of the pyriformis muscle, and through the obturator foramen, when it winding round the first ribs, and below the scalenus muscles; the right one gives off the common carotid trunk ; hence it is distinctively known as the brachio-cephalic artery, and is larger BRACHIAL ARTERIES. 419 than the left. Both pass forward between the layers of the anterior mediastinum, the right below, the left to the side of the trachea, and partly under the oesophagus. The following are the arteries given off alike by both brachials. The first four arise within the thorax, the next two at its entrance, while the last two arise externally. Dorsal. Superior cervical. Vertebral. Internal thoracic. External thoracic. Inferior cervical. Prescapular. Subscapular. Fia. 161. Arteries of the neck exposed on the left side, o, Anterior aorta; a'. Left brachial; a", Eight " brachial, or brachio-cephalic ; 6, Left dorsal ; c c, Superior cervical ; d, Vetebral ; e. Inferior cervical ; /, Cephalic or common carotid ; /', Left, and /", Eight carotid ; g g, (Esophageal twigs ; h h. Tracheal twigs ; i i, Muscular twigs ; /;, Thyroid ; I, Thyro-laryngeal ; m, Branch to Parotid gland. The Dorsal artery runs on the outer side of the trachea, oesophagus, sympathetic nerve, and longus colli muscle, through the second intercostal space, reaching the withers ; it supplies the muscles of that region. The anterior bran-ch goes to the splenius and complexus major, anastomosing with the terminal twigs of the cervical. Within the thorax, the dorsal gives off a few twigs to the mediastinum, and a large subcostal branch 420 ANGIOLOGY. which furnishes usually from the second to the fourth anterior intercostal arteries. The Superior cervical artery arises anterior to the dorsal, sometimes along with it, having the same relations until it passes through the first intercostal space. It then runs upwards along the ligamentum nuchse, covered by the complexus major, as far as the vertebra dentata, distributing branches to the muscles of the neck, and anastomosing with the dorsal and vertebral arteries. Within the thorax, it gives otf the first intercostal artery, and a twig to the mediastinum. The Vertebral artery arises opposite the first rib, gains the outer side of the trachea and oesophagus, and leaves the thorax, passing under the transverse process of the seventh, and through the foramina in the transverse processes of the sixth to the second cervical vertebrae, covered by the intertransversalis colli. On reaching the atlas it anastomoses with the retrograde branch of the occipital artery, or ramus anastomoticus, which comes through the posterior foramen on the wing of the atlas. Here it is covered by the obliquus capitis posticus muscle. It supplies branches to the muscles of the neck, also to the spinal cord and its membranes, through the intervertebral foramina. The Internal thoracic. Pectoral, or Mammary artery, ori- ginates at the first rib, opposite the vertebral. It descends to the second bone of the sternum, passing over the costal cartilages to the ensiform, where it splits into anterior abdominal, and asternal branches, after giving twigs to the pericardium and mediastinum ; and intercostal branches, which are distributed to the pectoral muscles, anastomosing with the external thoracic and first seven intercostal arteries. In the young it supplies the thymus gland. The anterior abdominal leaves the thorax at the ensiform cartilage, penetrates the rectus abdominis, and anastomoses with the epigastric artery. The asternal artery winds round the cartilages of the false ribs, crossing the digitations of the trans- versalis abdominis, and terminating in the thirteenth intercostal space, by anastomosing Avith the intercostal artery ; it supplies the diaphragm and transversalis muscles. The Inferior cervical artery is given off as the brachial leaves the thorax, passing between the jugular confluent and the pectoralis parvus, and dividing into ascending and descending branches. The former runs between the levator humeri and sub- scapulo-hyoideus, supplying the lymphatic glands and adjacent BRACHIAL ARTERIES. 421 muscles ; the latter lies between the pectoralis anticus and levator humeri, terminating in the pectoral muscles. The External thoracic or mam- mary artery arises close to the inferior cervical, turns round the anterior border of the first rib, and passes along the internal aspect of the pec- toralis magnus and parvus, a small branch accompanying the spur vein, and ramifying in the panniculus. The Prescapular artery arises from the brachial, in front of the tendon of the subscapularis, passing between it and the antea-spinatus ; it is accompanied by a vein and nerve to the dorsum scapulae, supply- ing the shoulder joint, pectoralis parvus, scapular muscles, and flexor brachii tendon. The Subscapular ■ artery arises at right angles from the brachial, just before it becomes the humeral, near the interstice separating the subscapu- laris and teres internus muscles. It passes up the inner side of the caput magnum, and terminates at the dorsal angle of the scapula, supplying branches to the latissimus dorsi, scapu- lar, and lateral thoracic muscles ; also the nutrient scapular, and the scapulo-humeral^ or posterior cir- cumflex artery, which passes outwards behind the shoulder joint, under the caput magnum and postea-spinatus, terminating in the external muscles of the region. When the brachial artery reaches the humerus it assumes the name of the humeral artery, just as the exter nal iliac becomes the femoral -as it Fig. 162. Arteries of the anterior limb— viewed from inside. 1, Brachial ; 2, Humeral 3, Anterior radial ; 4, Posterior radial; 5, Recurrent radial ; 6, Eadio-palmar 7, Large metacarpal ; a, Prescapular ; b, Subscapular ; V, Branch to latissi mus dorsi ; 6", Posterior circumflex V", Scapular nutrient and muscular branch; b"", Main branch supplying the muscles ; c, Antarior circumflex ; d, Humeralis profunda : e. Cubital ; e'. Nutrient artery of humerus; e", Branch to inferior brachial glands ; 6"', Descending branch forming supe- rior carpal arch ; e"". Anterior sub- cutaneous; /, Intsrosseous ; /', Branch to the carpus ; g. Muscular branches. passes the pelvic brim. 422 AJfGIOLOGY. HUMERAL ARTERY. (Fig. 162. 2.) The humeral artery, the continuation of the brachial, descends obliquely backwards, along the inner side of the humerus ; just above the elbow joint it divides into anterior and posterior radial arteries, or more correctly speaking it gives off the former, and is continued by the latter. Its principal branches are as follows : — Anterior circumflex. I Cubital. Humeralis profunda. | Coraco-radial. Anterior radial. The Prehumeral or Anterior circumflex artery passes between the two heads of the coraco-humeralis, reaches the front 'of the humerus, and terminates in the levator humeri, giving twigs to the flexor brachii, coraco-humeralis, and the shoulder joint, anastomosing with the posterior circumflex. The Arteria humeralis profunda arises near the conjoined tendon of the latissimus dorsi and teres intemus, is divided into two chief branches, which are distributed to the caput magnum and medium, the anconeus, humeralis obliquus, and extensor metacarpi magnus, anastomosing by one branch with the anterior radial artery. The Cubital or Ulnar artery passes backwards beneath the ficapulo-ulnaris, along the lower border of the middle head of the triceps extensor, down the forearm, between the external and middle flexors of the metacarpus, with the cubital nerve and vein, inosculating at the knee with the recurrent branch of the posterior radial artery, so forming the superior carpal arch. It gives off branches, to the caput medium, scapulo-ulnaris, pectoralis trans- versus, brachial fascia, and flexors of the leg ; also a nulrient artery to the humerus, and twigs to the elbow joint, with a small anterior subcutaneous branch The CoRACO-RADiAL artery, given off nearly opposite to the last, passes forwards to the flexor brachii muscle, dividing into ascending and descending branches. The Spiral or Anterior radial artery is given off at an acute angle, just above the condyle of the humerus. It descends over the anterior surface of the elbow joint, and beneath the flexor muscles of the fore-arm and origin of the extensor meta- carpi, where it meets the radial nerve. They travel together irt POSTERIOR RADIAL ARTERY 423 front of the radius, and approach the knee below the extensor pedis. It divides into numerous branches, which are distributed to the capsular ligament of the carpus and extensor muscles, arastomosing with the interosseous branch of the posterior radial artery. POSTERIOR RADIAL ARTERY. (Fig. 162. 4.) The posterior radial is the continuation of the humeral artery. It passes down the inner side of the fore-arm, with a vein and nerve, inclining backwards beneath the flexor metacarpi internus, and is sometimes described as dividing at the distal end of the radius into large and small metacarpals ; it can be felt just behind the insertion of the flexor brachii. It supplies twigs to the elbow joint, which anastomose Avith those of the ulnar, and muscular branches to the posterior region of the arm, with the following named branches : — Interosseous. | Radio-palmar. Recurrent radial. The Interosseus artery of the fore-arm comes off near the xadio-ulnar arch, through which it passes outwards, crossing the posterior surface of the radius below the perforans. It then pocam]n), and the transverse white fibres which pass, like the strings of a harp, between the pillars, form the lyra. The hippocampus (coi'mu Aonmonis) is the large eminence, constructed of white matter exter- nally and grey internally, which occupies the posterior part of the floor of the lateral ventricle. The liippocampi are continuous with the posterior pdlars of the fornix, and are separated from the optic thalami by the choroid plexuses. Posteriorly they diverge and enter the descending comua of the ventricles, occupying the cul-cU-sacs. Towards their terminations they become enlarged, and each presents a number of rounded elevations, with indented edges somewhat resembling the foot of an animal, and called the pes hippocampi. The external white matter of the hippocampi is continuous, through the corpora fimbriata; with the fornix and corpus callosLim. The coi'pus striatum is the pear-shaped prominence which 2i Fig. 179. Lateral ventricles opecod from ab ^°*°"' '^°^- ^- bathetic; «, , ' Trifacial ; /, Abducens ; g, Portio-dura ; and an inner, spread over the a, PorUo-moiiis; t, oiosso-pharyngeai; *, septum nasi. Pneumogastric: I, Spinal accessory: m, t^ Hypo-glossaL SECOND PAIR — OPTIC NERVES. The optic, or nerve of the special sense of sight, is a large nerve, which has its deep origin in the corpora geniculata, optic thalamus, and corpora quadrigemina ; the fibres from these three different sources uniting to form the optic tract, which winds round the brus cerebri to join its fellow, and form the optic com- missure. After leaving the commissure, the nerves become rounded, and diverge to pass through the optic foramina, where they receive a covering of dura mater, which immediately splits ^^^ NEUROLOGY. into two portions, one of which forms the periosteum of the orbit,, and the other a sheath for the nerve. After piercing the sclerotic and choroid coats of the eyeball, the nerve expands into the nervous retina. A little behind the eyeball, the nerve is pierced to its centre for the passage of a small artery, the arteria centralis retinae, which supplies the retina. In the optic commissure a peculiar decussation of nerve fibres takes place ; while the outer fibres of the optic tract continue their course direct to the eye of the same side, the innermost pass to that of the opposite side ; at the same time, some of the fibres cross from one tract to the other, and have no connection with the eyes; while others, it is said, proceed from eye to eye, without having commujiication with the brain. THIED PAIR — MOTORES OCULORUM. This, the common motor nerve of the eye, has its apparent origin on the inner side of the ems cerebri, close to the pons Varolii, its course lying between the posterior cerebral and anterior cerebellar arteries; its deep origin may be traced to the locus niger, pons Varolii, and corpora quadrigemina. It makes its exit from the cranial cavity through the foramen lacerum orbitale, into- the orbital fossa, where it divides into several branches, supplying the superior, internal, and inferior recti, inferior oblique, and levator palpebrae muscles, and also branches to the lenticular ganglion. FOURTH PAIR PATHETIC NERYES. This is a motor nerve, and the smallest of the cranial nerves ; it has its superficial origin by the side of the pons Varolii, but its^ deep fibres may be traced to the valve of Vieussens and the cor- pora quadrigemina. Winding round the cms cerebri, this nerve passes through the outer wall of the cavernous sinus, leaves the cranium through the foramen patheticum, and is distributed to the superior oblique muscle of the eye. It communicates with the sympathetic, near the cavernous sinus. FIFTH PAIR TRIFACIAL NERVES. Called also the trigeminal, this is the largest of the cranial nerves, and, being a nerve of common sensation, of motion, and indirectly,, perhaps, of special sense, belongs to the class of mixed nerves^ FIFTH PAIR TRIFACIAL NERVES. 495 It' resembles a spinal nerve in having its origin by two roots, sensory and motor, and in having a ganglion on the sensory root. It arises on the side of the pons Varolii ; and the sensory root, which is the larger, may be traced to the restiforra bodies and lateral columns of the cord, the motor root having its deep origin near the floor of the fourth ventricle. The nerve passes through, an opening in the dura mater, at the apex of the. petrous temporal bone, where the posterior root spreads out into a large ganglion, the Gasserian, the anterior root passing beneath without any connection. The Gasserian ganglion gives off the ophthalmic, superior maxillary, and inferior maxillary branches. Bight orbit opened to show the nerves of the eye. a a. Optic ; b. Motor oculi ; c, Patheti ; d. Ophthalmic division of fifth pair ; d'. Lachrymal ; d", Supraorbital ; d'". Nasal ; e, AbduceM ; ef, Eectus externus muscle ; /, Orbital branch of superior majcillary nerve. The Ophthalmic nerve, the smallest of the three divisions of the trifacial nerve, passes forwards by the outer wall of the cavernous sinus, in company with the third and sixth nerves, enters the orbital fossa through the foramen lacerum orbitale, and divides into three branches, the frontal, lachrymal, and nasal. The frontal or supraorbital nerve is a large, flat branch,, placed on the internal wall of the optic fossa ; it ascends parallel to the superior oblique muscle, passes through the supraorbital foramen, and, after giving a branch to the upper eyelid, divides 494: NEUROLOGY. into several branches, some distributed to the skin of the fore- head, others to the muscles above the eye. This nerve com- municates, and forms a plexus with the anterior auricular nerve. The lachrymal nerve, the smallest of the three, passes straight Tip to the lachrymal gland, which it supplies, together with branches to the muscles and tegument of the anterior part of the «ar, anas^"omosing with the anterior auricular nerve. The nasal or palpebro-imsal nerve, the largest branch of the ophthalmic, curves inwards between the retractor and levator oculi, and re-enters the cranial cavity through the internal orbital foramen, with the ophthalmic artery ; it then passes through the cribriform plate of the ethmoid, and divides into two branches, which ramify in the pituitary membrane on the walls of the nasal fossa. Before entering the internal orbital foramen, it gives off a long branch to the membrana nictitans and lower eyelid, another to the lachrymal sac, and sensory roots to the opnthalmic gang- lion. The Superior maxillary nerve leaves the cranium through the foramen rotundum, and gains the orbit in company with the internal maxillary artery, crosses the lower part of the orbit, enters the maxillary hiatus, passes through the infraorbital or dental canal, and emerges on the face, at the infraorbital foramen, where it divides into numerous facial branches. The lateral branches of the superior maxillary nerve are — 1. The orbital hranch, which leaves the trunk in the orbit, and is distributed to the eyelids and integument. 2. The anterior palatine or palato-maxillary, which enters the palatine foramen, and accompanies the palatine artery, giving branches to the palate and gums. 3. The posterior palatine, or staphyline, which accompanies the staphyline artery, and is distributed to the soft palate. 4. The spheno-palatine, or nasal, which passes through the spheno-palatine foramen, is distributed to the mucous membrane of the nasal chamber, and sends a branch to the spheno-palatine or Meckel's ganglion. 5. The dental branches, which are given off behind and in the infraorbital canal, consist of posterior and anterior ; the former supplying the molar teeth, and sending a branch to the maxillary sinus, and the latter furnishing nerves to the incisor and canine teeth. The terminal branches of the superior maxillary nerve, supe- FIFTH PAIR TRIFACIAL NERVES. 495 rior, middle, and inferior, are distributed to the nose, false nostril, upper lip, and muscles and integument of the face, and form intimate plexuses with branches of the seventh pair or facial motor nerves. The Inferior maxillary nerve, the largest of the three divisions of the fifth, unites with the anterior root of the nerve immediately after it passes through the oval opening in the dura mater, so that it is both sensory and motor. The course of this nerve is through the foramen lacerum basis cranii, and between Fig. 187. Nerves of the right side of the head— the maxillary ramus and cheek being rensoved. a, Superior maxillary branch of fifth ; a', Spheno-palatine ; 6, Orbital ; c. Branch of spheno-palatine ; d. Pala- tine : e, Superior dental ; /, Staphyline : o, Superior maxillary trunk entering infraorbital foramen ; g', Superior : g". Middle ; g"'. Inferior nasal nerves : li. Inferior maxillary branch of fifth ; i, Masseter ; k, Anterior deep temporal : I, Pterygoid ; m. Buccal ; b, Subzygomatic ; o. Inferior dental; o', Mental : p. Lingual ; p', Its superficial ; p". Its deep branch. the pterygoid muscles, to the inferior dental foramen, which it enters, and, passing through the lower jaw, makes its exit at the anterior maxillary or mental foramen, and terminates in the mental nerves. In its course it gives off masseter, buccal, internal pterygoidean, subzygomatic, lingual, mylo-hyoidean, and dental branches. The masseter branch is detached from the trunk at the base of the cranium, passing through the sigmoid notch in front of the 496 NEUROLOGY. temporo-maxillary articulation, and is distribxrted to the masseter muscle. It gives off branches to the temporal miiscla The buccal nerve is directed forwards, traverses the external pterygoid muscle, and is distributed to the buccinator muscle and to the mucous membrane of the cheek, descending to the com- missures of the lips and the labial glands. In its course it gives small branches to the external pterygoid muscle, a branch (the anterior deep temporal nerve) to the temporal muscle, and branches to the molar glands. The branches to the pterygoid and temporal muscles are for the most part motor, the others sensory. The pterygoid nerve supplies the pterygoid muscles. The suhzygomatic or superficial temporal nerve winds round the ramus of the lower jaw, and, passing between the parotid gland and the posterior border of the jaw, joins the nerves of the seventh pair. In its course it gives off twigs to the guttural pouch, parotid gland, and teguments of the temporal region. The lingaal, considered by some authorities as the gustatory or nerve of the special sense of taste, is the principal branch of the inferior maxillary ; its course lies between the ramus of the jaw and the pterygoid muscles, round which it winds anteriorly, to reach the base of the tongue, along the side of which, under the mucous membrane, it runs to the tip, giving off in its course numerous branches to the lingual papillae, the mucous membrane of the mouth and gums, and the sublingual gland. The lingual receives the chorda tympani branch of the facial, and anastomoses with terminal branches of the twelfth uerve ; it also sends a branch to the submaxillary ganglion. The mylo-hyoidean nerve distributes branches to the mylo- liyoideus and digas^ricus muscles, and twigs to the subma,xillary glands. The dental branches are given off in the dental canal, to supply the teeth of the lower jaw; one series supplying the molars, the other the front teeth. The mental or terminal branches of the nerve, issuing fix>m the mental foramen, are distributed to the lower lip, and com- municate with the facial nerve. -The sympathetic ganglia, communicating with the fifth pair, are the ophthalmic or lenticular, the spheno-palatine or Meckel's, ■and the otic. (See Sympathetic System.) SEVENTH PAIR — PORTIO DURA, OR FACIAL. 497 SIXTH PAIP. ABDUCENS, This is a nerve of motion, has its apparent origin close behind the pons Varolii, at its junction with the inferior pyramids, and its fibres can be traced to the inferior pyramids and lateral bundles of the medulla. From its origin it passes forwards through the foramen lacenim orbitale, in company with the third and the ophthalmic branch of the fifth il^:ve3, aad is distiibuted to tht abductor oculi, or external rectus, arid the external portign of the retractor oculi muscles. Fio. 188. Left Bide of the f*ee— shoTring the listribution of the facial portions of the fifth and the seventh nerves, a. Infraorbital ; 6, Masseter , c, Superior; d, Inferior branch of subzygomatic : c. An- terior ; /, Middle ; g. Posterior auricular ; h h, Posterior temporal ; i Cervical branch ; k, Styioia 1 1 1, Parotid branches ; m, Facial ; n n' n". Its superior portion ; o. Its inferior portion. NTH PAIR PORTIO DTJBA, OS FACIAL. This nerve has its apparent origin in a depression in the medulla oblongata between the olivary and restiform bodies ; its deep origin can be traced to the floor of the fourth ventricle and olivary fasciculus. From its origin it passes outwards, in company with the eighth nerve, along with which it enters the meatus auditorius internus, and thence into the aqueduct of Fallopius, ■2k 498 NEUROLOGY. where it bends upon itself and forms a slight enlargement, the genicular ganglion, making its exit through the stylo-mastoid foramen, where it lies deeply buried beneath the parotid gland. Afterwards, inflected forwards, it passes between the gland and the guttural pouch to gain the posterior border of the maxilla, round the cervix of which it turns, and, reaching the external surface of the masseter muscle, terminates in two or three branches, which anastomose with the subzygomatic branch of the fifth, forming the subzygomatic plexus. At the genicular ganglion the seventh nerve is joined by a slender cord, the Tiei^'e of Wrisherg, which is regarded by some authorities as the sensory root of the seventh, by others as a connecting medium between the seventh and eighth nerves. In its course the facial nerve gives off numerous branches ; some before leaving the bone, the intraosseous, and some after leaving it, extraosseous. The intraosseous branches are the superficial petrosal, which, leaving the genicular ganglion, re-enters the crauial cavity by the Fallopian hiatus, and passing through the cavernous sinus, it receives a branch from the cavernous plexus of the sympathetic. The nerve thus formed — the Vidian nerve — traverses the fissure and conduit of the same name and gains the orbital hiatus, where it joins Meckel's ganglion, to which it thus supplies motor and sympathetic roots. A little to the outside of the above, the lesser superficial peti'osal iurnishes motor fibres to the otic ganglion, and a small filament supplies the stapedius muscle. The cJiorda tyrnpani branch is given off in the aqueduct of Fallopius. It enters the cavity of the tympanum, passes through the middle of the chain of small bones, or auditory ossicles, and, leaving the C9,vity through the Glaserian fissure, after a short course under the pterygoid muscle, joins the lingual branch of the fifth. The last intraosseous branch is one which anastomoses with the pueumogastric. After emerging from the stylo-mastoid foramen, the facial nerve gives off styloid branches to the stylo-hyoid and digastricus muscles ; a cervical branch, which passes downwards below the deprimens aurem muscle to the panniculus and skin of the neck ; twigs to the guttural pouch and parotid gland ; and lastly, the anterior, posterior, and middle auricular nerves. The anterior auricular nerve ascends over the front of the ear, supplying the muscles and uniting with branches of the fifth. NINTH PAIR — GLCESO-PHAEYNGEAL. 499 to form the auricular plesus. It gives twigs to the anterior auricular muscles; to the orbicularis palpebrarum, and levator palpebrse superioris extern us. The posterior auricular nerve passes upwards with the posterior auricular artery, and supplies the posterior muscles of the ear and the skin. The middle auri- cular nerve enters the concha, to the inner surface and cartilage of which it is distributed. The terminal or temporo-facial branches' of the facial ijerve are in two sets ; an inferior,, which passes downwards to the lov;er lip and muscles of the side of the cheek and lower jaw; and a superior, which supplies the muscles of the nose and tissues of the upper lip. They anastomose with the terminal branches of the superior and inferior maxillary divisions of the fifth nerve, and, from the peculiar looped and radiate manner of their termi- nations, have obtained the name of pes anserinus. EIGHTH PAIR PORTIO MOLLIS, OR AUDITORY. The nerve of the special sense of hearing has its origin on the medulla oblongata, close to the facial nerve. Its deep roots are anterior and posterior, the one springing from the central grey matter of the medulla, and the other from the floor of the fourth ventricle. The auditory nerve enters the meatus auditorius internus in company with the seventh, and at the bottom of the passage divides into tv/o branches ; an anterior or cochlear, dis- tributed to the cochlea, and a posterior or vestibular, which supplies the vestibule and the remaining portions of the internal ear. NINTH PAIR — GLOSSO-PHARYNGEAL. This is a mixed nerve, principally distributed to the tongue and. pharynx, and it arises from the medulla, the fibres composing it being traceable to the restiform bodies and th'e olivary fasciculi. It pierces the dura mater through a distinct opening, and leaves the cranium through the foramen lacerum basis cranii ; pre- viously however presenting a gangliform swelling, the petrosal or AnderscK 8 ganglion, which rests on the petrosal bone. Leaving the cranium, it passes downwards and forwards, between the guttural pouch and pterygoid muscles, and along the posterior border of the comu of the os hyoides, to gain the base of the tongue, being distributed to the mucous membrane and substance, principally of the base and sides of that organ. 500 NEUF.OLOGY. Its branches are the nerve of Jacohson, given off from the petrosal ganglion, and distributed to the tympanum and its mem- brane ; filaments to the superior cervical ganglion ; a branch to the carotid plexus ; branches to the muscles of the pharynx ; and a communicating branch to the pneumogastric nerve, TENTH PAIR PAR VAGUM, OR PNEUMOGASTRIC. This is a mixed nerve, which originates by motor and sensory roots. Its apparent origin is from a groove in the medulla ob- longata, immediately behind the ninth nerve ; its deep roots can be traced to. the restiform bodies, olivary fasciculi, and the grey matter near the floor of the fourth ventricle. This nerve is remarkable for its extent ; for the numerous dissimilar organs to which it is distributed ; and for its free and extensive anastomoses with other cerebro- spinal, and with the sympathetic nerves. It pierces the dura mater in company with the eleventh nerve, and passes through the foramen lacerum basis cranii, previously pre- senting an oblong grey mass, the jugular ganglion. After leaving the cranium, the par vagum descends behind the guttural pouch, close to the superior cervicular ganglion, crosses to the inner side of the occipital artery, arid joining the common carotid, proceeds down the neck in the same sheath with that artery. After entering the thorax, the course of the nerve on either side varies. The right nerve, turning obliquely round the brachial artery, proceeds backwards by the side of the trachea to the origin of the bronchi, where li gains the under and right side of the oesophagus; while the left nerve passes along the anterior aorta, crosses the origin of the posterior aorta, and gains the upper and left side of the oesophagus, the two being continued to the stomach and the solar plexus. The branches of the par vagum are — 1. An anastomotic branch to the facial near its origin. 2. Numerous branches to the superior cervical ganglion. 3. A sensory-motor branch to the pharynx, which anastomoses with the pharyngeal branch of the nintk 4. The superior lai^ngeal, which passes to the sides of the larynx, which it enters through a hole in the thyroid caitilage, being distributed to the mucous membrane, and giving motor fibres to some of the muscles of that organ. 5. Filaments to the inferior cervical ganglion, two or three 1HNTH PAIR PAR VAGUM, OB PNEUMoGASTRIC. 501 large ones being given off by the right nerve, and one long small branch, by the left nerve, 6. The inferior, or recurrent laryngeal nerve. — On the right side, this nerve leaves the par vagum as it passes the first rib, and winds round the origin of the dorsal artery, to gain the side of the trachea. The left one is given off near the root of the lungs, and is inflected round the posterior aorta to reach the trachea. Passing up the trachea below the carotids, the nerves reach the larynx, and are distributed to all its intrinsic muscles excepting the crico-thyroideus, and giving off in their course the tracheal and the recurrent oesophageal nerves. Fio. 189. Ninth, tenth, eleventh, and twelfth cranial, first cervical, and part of the sympathetic nerves— the left maxillary ramus and parotid gland being removed, a, Carotid artery ; 6, Glosso-pharynr geal ; V, Its pharyngeal ; 6", Its Ungual branch ; c c, Pneumogastric ; c'. Pharyngeal ; c", Superior laryngeal ; d d' d", Spinal accessory ; e e, Hypo-glcssal ; /, Great sympathetic ; /', Superior cervical ganglion ; /", Anastomosis of sympathetic and pneumogastric ; g. First cervical nerve. 7. Cardiac branches which help to form the cardiac plexus. 8. Numerous branches at the root of the lungs, which form the bronchial plexus, from which branches are distributed to the divisions of the bronchi, and to the lungs. After this plexus is formed, each par vagum is continued along the oesophagus by a superior and an inferior branch. After a short course, the superior branches unite, and the inferior l)ranches doing the same, they accompany the oesophagus, one above and the other below, supplying it with numerous twigs, till they enter the abdomen through the oesophageal opening of the 502 NEUROLOGY. diaphrS/gm, when the inferior branch terminates at the lesser curvature of the stomach, in a plexus . which siends numerous, branches to the right sac of that organ ; and the superior branch, passing to the left of the cardiac orifice, becomes lost in the solar •plexus. In passing it gives numerous twigs to the left sac of the stomach, mingles its branches with those of the sympathetic from the hepatic plexus, aad anastomoses with the terminal twigs of the right nerve. ELEVENTH PAIR — SPINAL ACCESSORY. The eleventh is a nerve of motion, arising from the whole extent of the cervical portion of the spinal cord, running along between the roots of the spinal nerves, and after entering the cranium by the foramen magnum, it receives additional filaments from the medulla oblongata. It passes through the dura mater, in company with the tenth pair, and leaves the cranium through the foramen lacerum basis cranii. In the cranial cavity, it receives twigs from the par vagum, and after emerging there- from, is directed backwards under the superior extremity of the submaxillary gland, and passing down the neck, gains the border of the levator humeri muscle near the shoulder ; then mounting slightly upwards, it crosses under the cervical trapezius, and is lost in the dorsal trapezius and rhorciboideus brevis muscles. In its course it gives off numerous twigs to the superior cervical ganglion, to the maxillary gland, and a large branch to the stemo-maxillaris, levator humeri, and trapezius muscles, and receives branches from the first, second, third, fourth, fifth, and sometimes sixth cervical nerves. TWELFTH PAIR — HYPO-GLOSSAL. This, a motor nerve, has its origin in numerous filaments derived from the medulla oblongata. It makes its exit from the cranium by the condyloid foramen of the occipital bone, descends by the external face of the guttural pouch, and is distributed to all the muscles of the tongue, after communicating with the first ""^rvical nerve and superior cervical ganglion of the sympathetic. Spinal Nerves. The nerves which emanate from the spinal cord, and make their exit through the intervertebral foramina are collectively EXPLANATION OF PLATE VI. Nervous System of the Horse. 1. Brain. 13. Solar plexus. 2. Optic nerve. 14, Semilunar ganglion. a Superior maxillary nerve (5th). 15. Tiiimbo-sacral plexus. 4. Inferior maxillary nerve foth). 16. Anterior crural nerve. 5. Pneumo-gastric nerve. 17. Great sciatic nerve. 6. Medulla oblongata. 18. External popliteal nerve. 7. Right brachial plexus. 19. External saphenic nerve. 8. Musculo-cutaneous nerve. 20. Tibial nerve. 9. Median nerve. 21. Metatarsal nerve. 10. Radial nerve. 22. Radial portion of median nerve 11. Cubital nerve. 23. Metacarpal nerves. 12. Pneumogastric nerve. . 24. Digital branches. S.S. Sympathetic chain. c. Inferior cervical plexus. g. Gutteral ganglion. Sp. Great splanchnic nerve. _y.wi. Posterior mesenteric plexus. p. Pelvic plexus. CERVICAL NERVES. 503 known as the spinal nerves. They consist of forty-two or forty- three pairs, and are divided, according to the regions, into eight cervical, seventeen dorsal, six lumbar, five sacral, and six or seven coccygeal pairs. The whole of the spinal nerves originate by two orders of roots, superior or sensory, and inferior or motor ; the former, which are larger and more numerous, arising from the superior lateral fissure, and the latter from the inferior lateral fissure of the cord. In the intervertebral foramina there is a ganglion on each of the superior roots, underneath which the inferior root passes. The .union of the two roots constitutes the spinal nerve, which, almost immediately after it passes through the foramen, divides into two branches ; ' a superior, distributed to the spinal muscles and the integument which covers them ; and an inferior, longer and larger, distributed to the inferior and lateral parts of the trunk, and in some cases the extremities. The spinal nerve sends various communicating branches to the sympathetic system. CERVICAL NERVES (8 pairs). The first cervical nerve, the suboccipital of Willis, leaves the spinal canal through the internal foramen of .the atlas ; the second through a foramen in the anterior part of the axis, the succeeding five through the corresponding intervertebral fora- mina, and the eighth between the last cervical and first dorsal vertebra. Superior Branches. — The superior division of the first nerve, after reaching the interstice between the anterior oblique and the posterior straight muscles of the head, divides into numerous branches, which are distributed to the muscles at the back of the poll and to the retrahentes muscles of the ear ; . one long branch, which anastomoses with the posterior auricular branch of the seventh cranial nerve, to form the auricular plexus, is sent to the concha, and the skin covering it. The superior division of the second nerve, situated under the obliquus capitis posticus muscle, to which and the anterior oblique it gives branches, is distributed in a similar manner to the superior branches of the remaining cervical nerves. These, gradually diminishing in size as they proceed backward, pierce the intertransversalis muscle, and divide into superficial branches, distributed to the superficial muscles and skin, and the deejy branches, larger than the others, which cross the transverse pro- 504 NEUROLOGY. cesses, and form the deep cervical plexus, from which the deep muscles are supplied. Inferior Branches. — The inferior divisions of the cervical nerves gradually increase in size from the first to the last. They separate into two distinct groups, composed of the anterior six, which furnish branches to the muscles and skin of the breast, and of the lateral and anterior part of the neck, transmitting intercommunicating branches, which form a vast network known as the superficial cervical plexus, and which is traversed by the cervical branch of the facial and an important branch from the spinal accessory nerves. The last two, together with a branch from the sixth, join the two first dorsal nerves to form the brachial plexus. The inferior branches of the first cervical nerve pass through the foramen in front of the atlas in company with the occipital artery and vein, cross the rectus capitis anticus major muscle, and the spinal accessory nerve, and, describing a curve towards the top of the trachea, enter the subscapulo-hyoideus muscle, where they terminate in numerous branches. In their course they furnish filaments to the three recti muscles, to the thyro- hyoid, sterno-thyro-hyoideus, sterno-maxillaris, and the muscles connecting the hyoid bone to the laiynx, and communicate with the superior cervical ganglion, the spinal accessory, and hypo- glossal nerves. The inferior branch of the second cervical nerve descends under the posterior oblique, and is distributed by numerous branches to the rectus capitis anticus major and minor, levator humeri, deprimens aurem, retrahentes aurem, and subscapulo-hyoideus muscles ; to the outer side of the concha, and to the panniculus and skin, communicating with a branch of the spinal accessory and cervical branch of the facial nerves, and with the inferior cervical ganglion of the sympathetic. The inferior branches of the third, fourth, fifth, and sixth cervical nerves pass through the intertransverse muscle, and divide into deep and superficial branches, the one being distributed to the deep muscles of the neck and anterior part of the shoulder, and the other to the skin of the neck and the panniculus. The deep branches of the sixth and seventh, and a filament from the fifth help to form the phrenic or diaphragmatic nerve. The seventh cervical nerve, a very large nerve, passes between the two portions of the scalenus muscle, and helps to form the LUMBAE NERVES. 505 Irachial plexus. It receives an anastomosing branch furnished by the sisth nerve. The eighth cervical Tierve, larger than the preceding, also passes to the brachial plexus. It sends a branch to the inferior cervical ganglion. D0E3AL NERVES (17 pairs). The dorsal nerves, with the exception of the first, are all dis- tributed in a similar and very simple manner, as compared with the cervical nerves. The superior branches, passing up between the transverse processes, bifurcate, one branch being sent to the spinal muscles and the skin of the dorsal region, the other being distributed to the longissimus dorsi muscle. The inferior branches descend to the intercostal spaces, ::nd pass along between the pleura and internal intercostal muscles. Each of these intercostal nerves, at its origin, gives one or two branches to the sympathetic, and, towards its middle, a perforatina branch directed obliquely outwards to the skin, where it ramifies, pnd in Its course, gives oflf muscular filaments. The inferior branch of the First Dorsal nerve goes almost entirely to the brachial plexus. It has no cutaneous division and uc intercostal branch is very slender. llie Second Dorsal nerve sends a large branch to the bracbid plexus. Its intercostal branch, more considerable than th.H of the first, extends down to the sternum, and gives off cutaneous twigs. The Third, Fourth, Fifth, Sixth, Seventh, and Eighth UOEs.^L NiaiVES pass to the extremity of the intercostal spaces and are prolonged into the pectoralis magnus and rectus muscles • tnetast mne, after reaching the cartilages of the false r.-bs are' contmued into the walls of the abdomen, and under the internal oblique, to the rectus, where they divide, one division going to the substance of the muscles, the other furnishing twigs to the skin of the abdomen. The Seventeenth Dorsal nerve fur- nishes a large branch to the fleshy portion of the internal oblique, and another which anastomoses with the first lumbar nerve. LUMBAR NERVES (6 pairs). The Superior branches of the lumbar nerves are distributed to the muscles of the loins, and to the integument of the loins and croup. 506 NEUROLOGY. The Inferior branches send twi,srs to the sympathetic, and branches which anastomose with one another. That of the first lumbar nerve receives a branch from the last dorsal, and turning backwards under the transverse process of the second lumbar vertebra, passes between the transversalis abdominis and internal oblique, to which it sends filaments, and terminates in the rectus muscle. Near its origin, it gives off a perforating branch which, passing through the abdominal muscles, terminates in numerous cutaneous filaments. The inferior branch of the second lumbar nerve has similar anastomosing branches to the first, and two perforating nerves which, receiving a small branch from the third, descend under the skin of the internal and anterior face of the thigh, and are distributed to the skin of the flank and the crural region. The inferior branch of the third nerve, besides its anastomosing branches, sends usually three branches downwards and outwards to the inguinal canal, where they ramify in the cremaster muscle ; it also furnishes numerous twigs to thj8 psoas magnus. One of the inguinal nerves generally unites with a large branch of the fourth nerve. The inferior branch of the fourth lumbar nerve, besides the branches common to all, gives a large branch to the lumbo-sacral plexus, and a long branch which unites with an inguinal branch from the third. It is then directed downwards to the thigh, where it terminates in numerous cutaneous and aponeurotic branches. The fifth lumbar gives a large branch to the lumbo-sacral plexus, and branches to the psoas parvus. The sixth lumbar is the principal branch of the lumbo-sacral plexus. SACRAL NERVES (5 pairs). The sacral nerves, which diminish in size from the first to thfe last, have their origin close to each other, their roots surrounding the conus meduUaris, in which the spinal cord terminates, and by which it extends into the canal of the sacrum. With the coccy- geals they form the nerve tuft known as the cauda equina. The superior branches of the sacral nerves leave the spinal canal through the superior sacral foramina, and are distributed to the muscles of the superior region of the sacrum, and terminate in the skin of the croup. PHRENIC NERVE. • 50T The inferior branches, the first three of which assist in the formation of the lumbo-sacral plexus, converge at the side of the pelvic cavity. The fourth constitutes the internal pudic nerve, which, at its origin, sends an anastomosing branch to the origin of the fifth. It is distributed to the penis, where it terminates, by numerous branches, in the glans. Before leaving the pelvic cavity, it sends filaments to the muscles and skin of the perineo- ai-al region. In the female, this nerve is distributed to the parts analogous to those of the male. The fifth forms the anal or hcemorrhoidal nerve, distributed to the sphincter ani, and the skin covering it. Small filaments which form the pelvic or hypogastric plexus are given oflf from near the origins of all the sacral nerves. COCCYGEAL NERVES (6 or^ 7 pairs). The coccygeal nerves differ from the other spinal nerves in having no immediate communication with the sympathetic. They diminish in size from the first to the last. The superior branches unite to form one large nerve, which passes under the curvator coccygis muscle, and extends to the tip of the tail, giving off muscular and cutaneous filaments in its course ; the inferior branches likewise coalesce and extend in a similar- manner under the depressor muscle. The inferior branch of the first coccygeal receives a branch from the last sacral, and sends a filament down towards the anus and perinaeum. NERVES FORMED BY THE INFERIOR BRANCHES OF THE SPINAL NERVES. These nerves form three groups, as follows : — The Phrenic nerve, the Brachial plexus, the Lumbo-sacral plexus. PHRENIC NERVE. {Fig. 195. 9 g g.) The phrenic or diaphragmatic, the motor nerve of the dia- phragm, is formed by three principal branches; one from the brachial plexus, one from each of the sixth and seventh cervical nerves, with a filament, not constant, from the fifth. It enters •508 NEUROLOGY. the thoracic cavity, and passing to the inner side of the brachial artery, receives a filament from the sympathetic ; thence it travels between the two layers of the mediastinum, and reaching the aponeurotic centre of the diaphragm, divides into numerous branches, which are carried towards the periphery of the muscle. BRACHIAL PLEXUS. (Fig. 190.) The brachial plexus comprehends that large bundle of nerves formed of the inferior branches of the seventh and eighth cervical, the first and part of the second dorsal nerves, all of which converge to the interstice between the two divisions of the scalenus muscle, where they unite, and pass outwards round the ■first rib. At and below the arm, the plexus divides into numer- ous branches, distributed to the muscles and teguments of the anterior extremity ; the chief branches we describe as follows : — The Anterior scapular nerve is a large branch which supplies the muscles on the dorsum of the scapula ; it turns round the anterior border of the bone, a little above its neck, passing under the antea-spinatus, to which and to the postea- spinatus it gives twigs, terminating in the latter. The Thoracic nerve consists of six or seven branches of unequal size and length, usually distributed to the muscles between the shoulder and the trunk ; three anterior ones are ■directed obliquely downwards, losing themselves in the muscles attached to the sternum ; while of the three posterior branches, one, winding I'ound the posterior border of the caput muscles, becomes superficial, and is distributed to the panniculus and skin ; while the remainder are distributed to the latissimus dorsi and serratus magnus. The Subscapular nerve includes two principal cords, the smaller of which goes to the subscapularis, and the larger, the axillary or circumflex nerve, turning round the scapulo-humeral articulation, terminates in a subcutaneous branch which descends the arm. It supplies the subscapularis, teres externus, and levator humeri, and furnishes articular and cutaneous filaments. The Radial nerve, a large branch of the brachial plexus, is principally furnished by the first dorsal. It arises behind the humeral artery, and is directed backwards and downwards under the subscapularis and teres major muscles, being accompanied for BRACHIAL PLEXUS. 509^ a short distance by the artery. Near the deep humeral artery,, it turns round the back of the humerus, between the caput mag- num and humeralis obliquus, and passing down the outer surface of the bone, gains the anterior face of the elbow joint and radius, where it meets the anterior radial artery, and accompanies it almost as far as the carpus, supplying the extensor muscles of the forearm. In its' course it gives off branches to the caput Fig. 190. Internal aspecb of right anterior extremity — showing the brachial plexiis. a, Seventh cerrical nerve ; 6, Eighth cervical nerve ; c. First dorsal nerve ; d, Branch from second dorsal nerve ; c, Anterior thoracic ; /, Posterior thoracic ; g. Anterior scapular; h. Subscapular; i. Axillary; 7;, Cubital; I, Small mnsculo-cutaneous branch ; m, Radial; n,p, Median; o, Musculo- cutaneous. muscles and scapulo-ulnaris, to the elbow joint, and to the skin covering the arm. The Ulnar or Cubital nerve is formed of fibres from the dorsal nerves ; it is less than the radial, and originates on the outer side of the humeral artery, which it accompanies beyond the origin of the deep humeral artery ; crossing the latter, and 510 NEUROLOGY. WlBIl passing between the scapulo-ulnaris and caput parvum muscles, it gains the inner side of the elbow. Afterwards, descending to the bend of the carpus, it passes under the annular ligament and divides into two branches, one of which unites with a branch from the median, to constitute the external metacarpal nerve, and the other, traversing the space between the tendons of the flexor metacarpi externus and medius, is distributed by numerous branches to the skin covering the radius, carpus, and the outer side of the metacarpus. This nerve accompanies the artery and vein of the same name. In its course, the ulna nerve gives off, a branch which proceeds downwards between the scapulo-ulnaris and pectoralis trans versus, fur- nishing many filaments to the latter ; be- coming cutaneous, it is distributed to the skin below the elbow. It also furnishes a branch to the flexor metacarpi muscles. The Median nerve, composed of fibres from the two dorsal and the eighth cervical nerves, descends the humerus in company with the humeral artery to the inner side of the elbow, runs down the side of the radius till it reaches the carpus, and then, passing under the posterior annular ligament, divides into the internal metacarpal, and a branch to the external metacarpal nerve. In its course it gives off, under the brachial artery, a branch to the pectoral muscles ; and near the middle of the humerus, a long branch, the quuscuIo- cutaneous or antibrachial nerve, which passes obliquely under the coraco-humeralis and coraco-radialis muscles ; here it divides, one branch going to the humeralis externus, while the other, passing between this muscle and the coraco-humeralis, gains the inner aspect of the arm, where it becomes subcutaneous, and ramifies on the antibrachial fascia, sending its branches down to the carpus. The median nerve also supplies numerous filaments to the elbow joint, to the flexor muscles of the phalanges, and the internal flexor of the metacarpus. Fig. 191. Carpal and metacarpal nerves— internal aspect. q.Exterualbranch of medi- an ; r. Internal branch of median, or internal meta- carpal ; s, Internal branch of cubital ; s'. External branch of cubital ; t, Exter- nal branch of median, and internal branch of cubital uniting to form external metacarpal ; u, Anasto- motic branch uniting metacarpal nerves ; v, In- ternal digital. LUJ*uiu-SACRAL PLEXUS. 511 The Metacarpal nerves, external and internal, are formed, the fir^t by the union of a branch from the median and one from the cubital ; the second may be regarded as the continuation of the median. They run down the metacarpus by the sides of the flexor tendons, to which they give filaments, and terminate at the fetlock ; the internal nerve lies posterior to the great meta- carpal artery. Midway down the metacarpus, they anastomose by means of an oblique branch which crosses the flexor tendons posteriorly. At the fetlock, near the insertion of the suspensory ligament to the sesamoids, each metacarpal nerve divides into tliree digital branches ; anterior, middle, and posterior. The anterior branch descends in front of the digital vein, and distributes its branches on the anterior surface of the foot. The middle branch frequently anastomoses with the others, and always •with the anterior branch. It supplies the fetlock pad and sensi- tive sole. The posterior branch, by far the largest, and the true continuation of the metacarpal nerve, is continued behind the digital artery to the basilar process of the os pedis, entering the lateral fissure, and being distributed to the substance of the bone and the laminae. It gives ofi" branches to the flexor tendons, and a filament which is carried forwards and distributed to the sensitive frog ; minute filaments accompany the plantar ungual artery into the pedal bone. LUMBO-SACRAL PLEXUS. (Fig. 192.) This plexus, which supplies the posterior extremity, is formed by the inferi^ branches of the last two lumbar and the first three sacral nerves ; it is divided into two portions, an anterior or lumbar, and a posterior sacral, each of which has a large trunk for its centre. The anterior division is constituted by the above- mentioned lumbar nerves, receiving, after a short course, a branch from the fourth one ; the posterior division is formed by the first three sacral nerves, which unite to form a single bundle. These trunks are united by communicating branches. The anterior division is buried under the psoas parvus, and is separated from the posterior division by the internal iliac artery. The posterior division is placed within and on the side of the peivio cavity. The anterior division furnishes the iliaco-mus- -cular, crural, and obturator nerves. The posterior division gives 512 NEUROLOGY. off ilio-ynuscular and iscliio-muscvdar or lesser sciatic branches^ and terminates as the great sciatic nerve. The Iliaco-muscular are numerous small branches, the chief of which accompany the iliaco-muscular artery across the iliacus muscle. The Crural or Anterior Femoral nerve is the largest branch of the anterior division. It descends betvfeen the psoas magnus and psoas parvus, and passing under the sartorius, enters between the rectus femoris and vastus internus, distributing branches to these muscles. Near the groin, it gives off the internal saphenic nerve, which accompanies the femoral artery for some little distance, then passes between the sartorius and gracilis, becoming subcutaneous, and passing down the limb, in company with the internal saphena vein, and, on the inner face of the leg, it is continued to the hock, and by delicate branches as far as the fetlock and pastern. Another long subcutaneous branch is given off, which breaks up and surrounds the saphenic artery and vein. These branches furnish filaments to the stifle, to the adductor and pectineus muscles, and to the skin of the anterior and inner part of the leg. The Obturator nerve, situated at first under the peritoneum, accompanies the obturator artery through the obturator foramen, and gaining the muscles on the internal face of the thigh, ter- minates in the obturator extemus, adductors, pectineus, and gracilis, also giving twigs to the obturator internus. The Ilio-muscular or Anterior Gluteal nerves, four or five in number, leave the pelvis through the great sciatic notch. The principal branch loses itself in the gluteus maximus, another crossing the neck of the ilium, above the gluteus internus, is directed outwards, and distributed to the tensor fascise latse. Another passes to the gluteus internus, in the substance of which it terminates. The Ischio-muscular or Posterior Gluteal nerves are ihe superior and inferior. The first, the course of which lies through the sciatic notch, and between the sacro-sciatic ligament and the gluteus maximus muscle, to the posterior portion of which it gives a small branch in passing, and sends another to the gluteus externus, terminating by numerous branches in the triceps abductor muscle. The second is situated below the preceding, and supplies the biceps rotator tibialis muscle and skin of the posterior part of the haunch. LUMBO- SACRAL PLEXUS. 513 The Great Sciatic nerve, the largest nerve in the body, leaves the pelvis in company with the gluteal nerves, through the great sciatic notch, and is directed downwards along the posterior face of the femur. Near the stifle, it passes between the two portions of the gastrocnemius muscle, where it forms two branches ; a short one, which enters the muscles attached to the posterior part of the tibia, and is distributed to the flexor pedis, popliteus, and flexor pedis accessorius muscles ; and a principal Flu. 192. Lumbo-sacral plexus of the right side — the pelvis opeied a id viscera removed, a. First lumbar nerve : a' a", Its branches ; 6, Second lumbar nerve : c. Inguinal branch : d. Femoral cutaneous : e. Crtiral ; e'. Internal saphenic ; /, Obturator : g, Anterior; and h, Posterior gluteal; i, Posterior cutaneous branch; fc. Internal pudic ; k', Its perineal branch : fc", Dorsal branch to the penis; I, Haemorrhoidal ; to m, Great sciatic : m'. Posterior crural : m". External popliteal : m'", External saphenic : n. Muscular branch ; o, TibiaL branch, the tibial or popliteal nerve, which descends at the posterior part of the tibia, below the flexor perforatus, and divides at the hock into external and internal metatarsal branches. In its course, the sciatic nerve furnishes filaments to all the muscles situated at the posterior part of the thigh, with 2l 514 NEUHOLOGY. two important braoches, the external popliteal and external saphenic nerves. The External Popliteal nerve leaves the great sciatic about the level of the geraelli muscles. It passes between the adductor magnus and gastrocnemius, and arrives at the supe- rior extremity of the leg, behind the lateral ligament of the femoro-tibial articulation, when it terminates in two branches; one, the anterior tibial nerve, is short, and enters the muscles attached to the superior extremity of the anterior face of the tibia, in which it ramifies ; the other the rausculo-cvianecnis nerve turns downwards by the outer side of the anterior surface of the leg, and, passing the hock, metatarsal bone, and fetlock, terminates at the pastern. It gives off numerous muscular and cutaneous filaments. The External Saphenic nerve is given off shortly before the great sciatic enters the gastrocnemius muscle, descending under the fascia which covers the latter, and accompanying the external saphenic vein. It passes the tarsal joint, and ramifies on the external aspect of the metatarsus, some of its filaments reaching the digital region. In addition to the above, a small nerve is given off from the great sciatic to supply the ischio-femoralis, gemelli, and obturator intern us ; also a large branch, the posterior crural, aris3S as the sciatic nerve bends downwards over the femur, and supplies the muscles of the lateral and posterior femoral regions. A fasciculus of nerves, given off as the sciatic enters the gastrocnemii, assists in supplying the posterior tibial group -^i jauscles. The External and Internal Metatarsal InERves, formed by the bifurcation of the great sciatic, pass down the side of the flexor tendons, and terminate as the digital nerves. Towards the superior extremity of the cannon bone, the external metatajrsai nerve is earned outwards between the splint bone and the tendon, while the internal one is placed on the inner side of the tendon, and foUows the posterior border of the inner splint. The digiiui nerves are distributed in a similar manner to those of the fore foot. Pio. 193. Tarsal and metatarsal nerves —internal aspect. « mappropriately, ^ anterior angle ; d, Supero-posterior aS the chief OTQOiTi of eXJOTCSStOTh in 'angle; e, Anterior border; /, Poste- +1, f '1 rior border ; 3, Snperkurborder. tliat animaL Fio. 197. Eight conchal and an- Bular cartilages. 1, Con- chal cartilage; a.Sttperior extremity ; 6, Inferior extremity ; c, Outer sur- face ; d, Inner surface : e. External border; /, In- ternal border; 2, Annu- lar cartilage ; g, Anterior surface ; h, Superior; and i, Inferior border. MIDDLE EAR. The middle ear or tympanum is an irregular bony cavity within the petrosal bone. It is bounded externally by the membrana rpani or drum of the ear ; internally by the bony walls of internal ear ; anteriorly by the Eustachian tube ; and pos- teriorly by the mastoid cells. The Membrana tympant is a semi-transparent, nearly circular membrane, vsdth its middle drawn inwards. It is inserted to a MIDDLE EAU. 527 groove round the inner end of the external meatus, and is com- posed of three layers ; an ext&i-nal, or epidermic, a prolongation of the skrn lining th« meatus ; a middle, or fibrous, the fibres being in two sets, one radiating from the centre to the circum- ference, the other scattered and indistinct, except near the periphery, where they form a dense ring ; and an intermal, or mucous, derived from the mucous lining of the middle ^r. A chain of small bones, the auditory ossicles (ossicula auditus) stretch across the tympanum. Thev are the malleus, incus, stapes, and len- ^ ,?' tt j J J > r -J The malleus, a, Head; ticular bone, or os orbiculare. 6, Neck ; c. Handle ; The Malleus, or Hammer, presents a '^. ^p«x=«^ 8™<^- rounded head (capituluTn), a neck, a liandle (man/iibriu'iirh), a long and a short process (processus gracilis and brevis). The head articulates with the incus ; the handle is received between the inner and middle coats of the membrana tympani ; the long process, in man, extends to the Glaserian fissure ; and the short process, very obtuse, lies in contact with the drum. The Incus, or Anyil, which in shape somewhat resembles the bicuspid tooth of man, has a body and two crura or processes. The body is concave on its surface, and articulates with the head of the malleus; the short cms is connected with the posterior wall of the tympanum ; and the incus" "af" Body; b, long crus bears the os orbicidare, a round Articuiar^aceforrmd- bone, about the size of a grain of sand, at its Long cms; e, oa orwcn- extreme point. ^®" The Stapes, or STnmup, possesses -a base, two crura, and a. head. The base is oval, and placed upon ± the fenestra ovalis ; the. crura converge irom ^'Mri each extremity of the base to a constricted ^»» portion termed the neck, on which is placed p^^j ^^ the head, which articulates with the os orbi- stapes, a, Head; 6 », Culare. crura ; c. Base. Th^ inner wall of the tympanum is very uneven, and presents several eminences and openings. The oval opening, near its upper part, is the fenestra ovalis, which leads into the cavity of the vestibule. Above this fenestra, between it and the roof, is a ridge formed by the aqueduct of Fallopius, and beneath is the round opening of the fenestra rotunda. The Fig. 200. 528 lOLOGFY. latter opeoiiig leads into the cochlea, and in the recent subject is closed by the lining membrane of the cavity ;. between the two fenestrse is the projegtion termed the promon- tory. At the posterior part of the tympanum, numerous open- ings lead into the rrmstoid cells, which are small, irregular, freely-communicating cavities in the auditory bulb of the temporal bone. Behind the fenestra ovalis is a conical eminence, the pyramid, in the apex of which is a groove for the tendon of the stapedius muscle. The anterior part of the tjanpaaum narrows towards the opening of two canals, separated from each other by a lamina of bpne, the processus cocrdearifonniy ; the upper and smaller of^ these canals contains the tensor tympani muscle, and the other leads into and forms the bony portion of the Eustachian tube ; a tube partly osseous and partly cartilaginous, which extends from the tympanum to the guttural pouch, and is the passage tlirough which air is supplied to the middle ear. Tlie Glaserian fissure is immediately in front of the ring to which the membrana tympani is inserted. Th'^ bones of the middle ear are united and kept in their positions by muscles and ligaments. The muscles are the stapedius, which has its origin in^ the interior of the pyramid, and is inserted into the neck of the stapes; the tensor tympani, which arises from the cartilaginous portion of the Eusta- chian tube, and surface of the sphenoid, and passing through a small canal, becomes inserted into the handle of the malleus ; the laxator tympani, which arises from the sphenoid, and passing through an opening in the Glaserian fissure, is inserted into the neck of the malleus. The ligaments are the suspensory, whicli attaches the head of the malleus to the upper wall of the tympanum ; the posterior, which attaches the short cms of the incus to the margin of the mastoid ceUs ; and the annular, which attaches the foot of the stapes to the membrane closing the fenestra ovalis. The tympanum is lined by a vascular mucous membrane. Fia.202. External wall of the "tympamun — viewed from within, a, Meatus audi- torius extemus ; b, Tympanic mem- brane ; c. Malleus ; d d. Mastoid cells ; e e, Outer boundary, or ring of tym- /, Orifice for Eizstachian pamam; tube. INTERNAL EAE. 529 which is continuous, through the Eustachian tube, with that of the guttural pouch and pharynx, and is reflected into the mastoid cells. The whole of this membrane is lined with epithelium, that in the tube being ciliated. INTERNAL EAR. The internal ear, from its complexity termed the labyrinth, is the ultimate part of the organ of hearing. It consists of a cavity whose boundaries include an osseous outer, and a membranous inner por- tion, respectively termed the hony and the mem- branous labyrinths. The bony labyrinth is an irregular cavity, divided into three separate parts; the vestibule, semicircu- lar canals, and cochlea. The Vestibule is an irregular, oval - shaped cavity, situated between the cochlea and the semi- circular canals, having the fenestra ovalis pene- trating its outer wall, and the five round open- ings of the semicircular canals at its back. At the upper part of its inner wall are two de- pressions, the fovea elliptica and fovea hemispherica, separated by a ridge, the emi- nentia pyramidalis, all of which are pierced by numerous small open- ings, macula cribrosa, for the passage of nerve filaments. • Behind the fovea hemispherica is the opening of the aqueduct of the 2 M Diagram of the ear. In the internal portion, the black part shows the cavities of the bony, and the white part those of the membranous labyrinth. Ovi, Cavity of the concha ; aG, External auditory meatus; Tr, Tympanic membrane ; Ct, Tympanum ; Ak, Auditory ossicles ;. Fr, Fenestra rotunda ; ER, Eustachian tube ; L, Guttural pouch ; Sac, Sacculus ; ut, Utricle ; oB, uB, Bony ; Co, hB, Membranous semicircular canals ; De, Aquasductus vsstibuli ; Se, Saccus endolymphaticus ; St, Scala tympani ; Sv, Scala vestibuli ; Con, Scala intermedia ; +, Its vestibular caecal sac ; Cr, Ductus reuniens ; *, Its apex : Dp, Aquaeductus cochleae, vel Cotunnii. 530 ^STHESIOLOGT. vestibule, which extends to the posterior surface of the petrosal bone, and gives passa^je to a diverticulum of the membranous labyrinth. At the lower and anterior part of the vestibule is the large opening, apertura scales vestihuli, or vestibular canal cf the cochlea. The Semicircular canals are three half-circular passages communicating with the vestibule, into which they open by both extremities, and having, near one extremity of each, a dilatation termed the ampulla. These canals are distinguished as superior or perpendicular, posterior or oblique, and inferior or hori- zontal. The anterior or dilated end of the superior canal enters the vestibule by a distinct orifice, while its posterior or non- dilated end joins 'the anterior non-dilated end of the oblique ; thus the two enter the vestibule by one common opening, the posterior end of the oblique canal being dilated, and entering by a distinct opening. The inferior canal has two openings, of which the anterior is dilated. The Cochlea, or Snail shell, is the anterior division of the labyrinth, and the most complex of the three. It consists of a gradually tapering spiral canal, which takes two and a-half turns round a central axis. This axis, termed the modiolus, is widest at its base, where it is pierced by numerous small openings, through which pass the filaments of the cochlear branch of the auditory nerve. The spiral canal is divided into two compart- ments (scalce) by a partition, partly bony and partly membranous, the lamina spiralis, which is wound spirally around the medio- lus in the direction of the canal, and terminates, at the apex of the cochlea, by a hook-shaped process, the hamulus. The two compartments are thus completely separated, except at the apex, where they communicate by means of an opening, the helicotrema, under the hamulus ; inferiorly, one scala terminates in the vesti- bule, it is hence called the scala vestihuli ; the other leads to the tympanum at the fenestra rotunda, and is called the scala tympani. The whole of the bony labyrinth is lined by a thin fibro- serous membrane, which closes the openings of both the fenestra rotunda,' and fenestra ovalis, and, adhering to the bone, acts the part of a periosteum. The inner surface of this membrane is smooth, and secretes a thin limpid fluid, the perilymph or liquor Cotunnii, which entirely fills the cochlea, and in the canals and vestibule, separates the bony from the membranous labyrinth. INTERNAL EAR. 531 Fi.i. 204. Membranous labyrinth. C, Ductus cochleari.« : K, Its cochlear blind end, and F, Its vestibular blind end ; Cr, Ductus reuniens ; 6', facculus : U, Utricle ; R, Aquseductus vestibuli. The Membranous labyrinth, though smaller in size, is nearly the counterpart in form of the vestibule and semicircular canals, and consists of two sacks within the vestibule, the larger of which, the utricle or sacculus communis, is elongated and lodged in the fovea elliptica ; the smaller, the sacculus or sacculus proprius, is round, and lodged in the fovea hemispherica. The semicircular canals, which are about one-third the size of the bony canals, open by five orifices into the sacculus communis. The sac- culus and utricle are united by an angular duct, which also leads to the aqueduct of the vestibule, a canal termi- nating in a blind dilatation, the saccus endolymphaticus. The bony lamina spiralis being incomplete, the division is completed by two membranes, the membrane of Reissner and the basilar membrane, between which is the scala intermeclia or ductus cochlearis, a tube which thus follows the turns of the cochlea, originating at its apex in a blind extremity, and terminate ing in a tube, the ductus reuniens, which unites it to the sacculus. This labyrinth is filled by a limpid fluid, termed the endolympli •or liquor Scarpce, and is constructed of four coats ; an external serous, a vascular, a nervous, and an inner serous, from which the endolympli is secreted. Within the sacculi are small, rounded, calcareous bodies, the 'onsideration of the hoof or horny case, and the pa"ts containeii within it. HOOF. The hoof of the horse corresponds to the finger-nail of man, but it is developed over the sides, and plantar aspect of the distal phalanx, thus forming a protective horny case, enveloping^ the inferior extremity of the digit. It is applied in an exact manner to, and united most intimately with, the sensitive struo- WALL. 545 tures which lie within, this union being effected by reciprocal depressions and elevations of the two surfaces, which fit into or receive each other. The general form of the hoof somewhat resembles that of the section of a cylinder which has been cut obliquely across. By maceration, the hoof is divisible into three distinct parts ; the wall, the sole, and the frog, which we will endeavour to describe separately. WALL. The wall is that part which is visible when the hoof rests on the ground, and is generally divided into the toe, quarters, heels, bars, internal and external surfaces, and superior and inferior borders. The toe forms the front of the hoof, and is the deepest as Trell as the thickest part of the wall, which gradually declines in height as it passes backwards to form the quarters ; these occupy the space between the toe and heels. The wall decreases in thickness from before backwards, more markedly so at the inner portion. It also apparently decreases in obliquity ; but on careful examination, it is found that the fibres of the quarters have the same degree of obliquity as those of the toe. At the posterior part of the foot, the wall takes on each side a sudden bend, forming an acute angle, and is continued inwards to the centre of the foot, where the two parts unite with the sole. The angles of inflection are called the heels, the inflections themselves the bars ; these latter forming stays to the quarters. The ex- ternal surface of the wall is convex, smooth, and covered by a thin layer, the periople, which is continuous above with the coronary frog band. The internal surface of the wall presents throughout its whole extent white, parallel, perpendicular plates or processes of horn, the so-called keratophyllous tissue, which extend from the coronary border to the sole, and are continued over the inner surface of the bars. These insensitive or horny lamina vary from 500 to 600 in number, and are separated from each other by deep fissures, in which are inserted the sensitive laminse. In the fresh subject the horny laminae are soft, elastic, and consist of two layers of fibres ; one running parallel with themselves, and others obliquely projecting from them. The superior or coronary border of the wall presents an excavation or groove, which slopes somewhat obliquely down- wards and inwards, forming a circular gutter, the cutigeral 2n 546 iESTHESIOLOGY. groove, in which is lodged the coronary substance or hand. In this srroove are numerous minute orifices, in which are inserted the secretory villi of the coronary band. The infeo'ior border is that part in contact with the ground, and to which the shoe is fitted. In an unshod animal it is always in wear, and protrudes beyond the rest, more especially round the outer quarter, and is known as the spread. The inner surface of the inferior border is united in a very intimate • manner with the periphery of the sole. The external layer of horn in the wall is distinctively known as the crust, and is secreted by the coronary band ; the rest being secreted by the sensitive laminae. Supposing the hoof to rest on a perfectly level plane, the line joining the toe to the middle of the coronary border should make with the ground an angle of about 5 degrees in the fore, and perhaps a little more in the hind feet. An angle exceeding or falling short Fio. 211. to any extent of this, would Detached hoof— supero-iaterai view, a, Crust, indicate defective Conformation. or outer layer of the waU ; b Homy lamina,; j ^j^- particular, hoWCVCr, it c, Supenor border ; d, Cutigeral groove ; e, Inner _ 1 ' ' surface of sole ; /, Inner surface of frog ; /', Frog- is nCCCSSary tO make alloW- **''■ ances for many circumstances, such as the breed and age of the animal, the condition of the foot, &c,, which may influence the angle. SOLE. The sole is a thick plate of horn, which helps to form the inferior portion of the hoof. It is comprised between the inner border of the inferior part of the wall and the inflections or bars, a,nd presents two surfaces and two borders. The inferior or external surface forms a vault, which is more or less concave in different animals. The superior or internal surface is unevenly convex, and is studded with a number of small orifices, which run obliquely forwards ; into these are inserted the vascular papillae of the sensitive sole. The external border or circum- ference of the sole is convex, abuts upon, and is united through- out its whole extent to the internal part of the inferior border of FROG 547 the wall, the union between the two being very intimate, through the intervention of homy matter. The inner border represents a deep cut or notch, in the form of the letter V, and is related with the bars, excepting at the narrow part, where it is bounded by the frog. The two angles uniting the outer and inner circum- ferences correspond to the heels, and are received between the wall and the bars ; this part of the sole covers the region which is most liable to injuries, especially to bruises or corns. FROG. The frog is the prominent, somewhat pyramidal mass of spongy horn lodged between the bars, and filling up the trian- gular space. It has four surfaces, a base, and an apes. The inferior or external surface is very irregular, and presentsalongitudinal triangular cavity, which varies in breadth and depth, being broadest and deepest in well- formed' feet. This cavity is the cleft of the frog, boundmg which are two sloping projections or branches, which unite at the apex of the frog anteriorly, and diverge posteriorly where they join the heels. The superior or internal surface is also very irregular, but ex- actly the reverse of the inferior ; where the one is hollow the other has a pro- jection, and vice versa. It presents over its whole surface numerous small fora- mina, into which are inserted the vascu- lar or secreting papillae of the sensitive frog, likewise' a triangular excavation, which is divided posteriorly into two lateral gutters by a long projection or elevation, corresponding to the cleft on the outer surface. This somewhat conical eminence is called the frog-stay, and it assists in establishing a firm union between the horny and sensitive frogs. The lateral surfaces incline obliquely from above downwards, and from without inwards. In their upper third they are firmly united to the ' external surface of the bars, and anteriorly, to the notch in the sole. Between the inferior Fio. 212. Solar aspect of the hoof, a a, Bars ; 6 b, Solar border of wall ; c c, Line of union between wall and sole ; d, In- ferior aspect of sole ; d' d', Posterior branches of ^ole ; e, Cleft of the frog ; e' e*, Lateral segments of frog ; //, Bulbs of the frog; g. Point of the frog. 548 ^STHESIOLOGY, part of the lateral surfaces of the bars and the frog are deep triangular hollows, called the commissures of the frog. The base or posterior extremities constitute the heels or bulbs of the frog ; these are two round flexible and elastic eminences, formed by the two extremities, and separated by the cleft. They cover the two angles of inflection of the walls, and are continued round the external part of the superior surface of the wall in the form of a band, which is the coronary frog band; it is from the inferior border of this that the thin covering of the hoof is continued. ». -p. __ - The summit or toe of the frog is the anterior pointed portion, which is inserted into the narrow part of the notch in the sole. HORN TISSUE. The horn of the hoof presents a fibrous appearance, very distinct in the wall, less so in the deep-seated parts of the sole and frog, and scarcely traceable in the superficies of the sole, where there is a continual disintegra- tion or separation of the horn in layers more or less extensive. It consists of minute cylindrical tubes or fibres, which have a direc- tion obliquely downwards and forwards, and are arranged in parallel rows, forming layers, placed one over .the other, and internally lamellae or plates, the whole united together by an amorphous or intertubular substance. Besides tha fibres, plates, and intertubular substance, there i^s always more or less pig- mentary matter, which consists of colour-cells distributed amongst the concentric plates or layers forming the walls. The horny fibres of the sole hs.ve the same obliquity as those of the walls, are secreted from the villi on the sensitive sole, and finally united to the wall round the outer circumference ; they receive a few villi from the inferior extrem-ity of each sensitive lamina. The horn of the frog differs considerably from that of both wall and sole. The tubes are much finer and softer, and have a flexuous arrangement They are united to those of the walls a^ Fio. 213. Transverse section of the horn of the wall magnified, o, Periople ; b, Horn tissue ; c c, Homy laminae ; d d, Sensitive laminas. SOFT STKUCTURES OF THE FOOT. 549 the base, and are secreted from the papillae on the surface of the sensitive frog. The fibres of the coronary frog-band are very fine, and are continued by a delicate layer of fibres, which covers the external surface cf the wall. Horn is tough, elastic, flexible, and admirably adapted for protecting delicate parts ; it is secreted in the form of cells, x- iiich become elougated. The colour of the hoof vanes, but it generally corresponUo iii depth with that of the neighbouring skin. It 'is an acknowledged fact, that white hoofs, like white skin, are more delicate, porous, and prone to disease than dark ones. SOFT STRUCTURES OF THE FOOT The parts contained ivithin the hoof are the os pedis, oa bavi- culare. the distal extremity of the os coronae, the ligaments by which these are connected together, the insertion of the extensor pedis and flexor perforans tendons, and the vessels and nerves. These have been described in their respective sections ; but there are also certain structures proper to the foot which it is necessary to describe here — viz., the lateral cartilages, sensi- tive frog, coronary band, sensitive laminae, and sensitive sole. The Lateral cartilages are two thin plates composed of hyaline cartilage in the middle, partaking more of the nature oi fibro-cartilage towards the borders. They are of an irregularly quadrangular form, and surmount the wings of the cofiin bone , •each presents two surfaces and four borders. The external eurface is convex, the internal one concave, presenting numerous vascular grooves, and is continuous postero-interiorly with the sensitive frog. The superior border is thin, generally convex, and pierced by several foramina for vessels to pass to the frog; the inferior border is attached to the wing of the os pedis posteriorly, it is inflected inwards, and is continuous with the inferior surface of the sensitive frog ; the posterior border is slightly convex, and has a direction obliquely downwards and backwards, joining the superior and inferior borders, being separated from the former by an obtuse angle ; the anterior border, also directed obliquely downwards and backwards, be- comes intimately blended with tli^ anterior lateral ligament of the coffin joint. The anterior borders of the two lateral cartilages are united by fibrous expansions from the extensor tendon and the above-mentioned lateral ligament 550 -ESTHESIOLOGY. SENSITIVE STRUCTURES. Attached to the inner surface of the hoof is the sensitive portion of the foot, which may, like the hoof itself, be divided into the regions of the wall, the sole, the frog, and the coronary- band. The extremity of the digit has been regarded not inaptly, as being enveloped in a sensitive sheath, which extends upwards beyond the level of the coffin joint, and becomes continuous with the skin. This sheath has been called the keratogenous mem- brane, since on its outer surface it is endowed with the function of secreting horn tissue, for the renewal of various parts of the hoof The part of this membrane which forms the ^ coronary band is villous or papillated ; that forming the sensitive wall is laminated, constituting what has been termed the podophyllous tissue ; finally, that forming the sensitive sole and frog is finely villous, and may be called the velvety tissue. The Sensitive frog occupies the pos- terior and central parts of the foot, filling up the irregular space between the lateral cartilages, flexor tendon, and os pedis. Bounded laterally by the cartilages, superiorly by the perforans tendon and common integument, infero- externally by the horny frog, it is continuous with the sensitive bars and sole, and the coronary ligament. Like the homy frog, it presents two surfaces, two lateral borders, a base, and an apex. The supero-anterior surface is related with the strengthening sheath of the flexor tendon, the ligament of the navicular joint, and the alse of the os pedis ; the infero-posterior surface is covered by villi, from which the homy frog is secreted, and in its centre is a deep cavity for the insertion of the frog- stay. The base looks backwards, and is divided into two bulbous enlargements, which are united to the lateral cartilages. The summit looks forwards, and is attached to the plantar surface of the OS pedis in front of the semilunar ridge. The lateral surfaces correspond to the commissures of the frog, and are continuous with the inner surface of the lateral cartilages. The sensitive frog is niade up of an external layer of cuticular structure, the Sensitive foot— solar aspect. a. Velvety tissue of the sole ; b, That of frog. SENSITIVE STRUCTURES OF THE FOOT. 551 villi of which secrete the horny frog ; below this is a layer of capillary blood-vessels ; its substance is made up of connective tissue, intermixed with yellow-fibro-cellular tissue of a peculiar elastic nature, which used to be described as fat. The Coronary substance, or coronary band, formerly called the coronary ligament, is that vascular structure Avhich occupies the cutigeral groove on the superior border of the wall. It consists of a dense fibrous mesh or band, which is connected with the coffin bone and extensor tendon by the medium of dense cellular tissue, Keposing on this is a plexus of blood-vessels, which is covered by a modification of the true skin, containing numerous papillae, which enter the funnel-shaped openings in the crust, the horn of which is thus secreted. The coronary band presents along its upper border a narrow" lip or process — the periojMc ring — which secretes the horn of the periople. The Sensitive lamina (podo- phyllous tissue) are the continua- tion of the coronary substance, and are attached to the coffin bone by a dense fibrous membrane, in which ramifies the vascular plexus emana- ting from the bone. These highly- organised plates are interposed between, and firmly attached to, the homy lamine3 on the wall, and are covered by minute papillae, which secrete the horny laminae ; on their inferior extremity are a few papillae, which help to secrete the homy sole. The Sensitive sole, continuous with the sensitive laminae and frog, is firmly attached to the coffin bone ; like the sensitive laminas, it is made up of a fibro-vascular membrane, clothed by a continuation of the corium, which is covered by the villi which secrete 'the horny sole. For the circulation of the foot, see pp. 417, 439; for its nerves, pp. 511, 514. Sensitive foot— lateral view, a, Corc- nary band ; 6, Podophyllous tissue. 552 COMPARATIVE ^STHESIOLOGT. COMPARATIVE ^STHESIOLOGY. RUMINANTIA. The concha of the ear is widely opened, projects outwards, and is less mobile than that of the horse ; the internal and middle ears present no feature worthy of note, except that the handle of the malleus is more curved. The tapetuiD lucidum of the eye is of a golden green colour, inclining to blue at the circum- ference. In all the domesticated animals the gland of Harder occurs ; and in other respects generally the eye of the ruminant resembles that of the solipede. The hair on the tail of the ox, like that of the ass, is long only at the extremity, where it forms a tuft. About the frontlet— i.e., between the horns — the hair is thick and curly, but in a degree varying in different breeds. The wool found on some of the smaller ruminants may be regarded as a modification of hair. The horns, or weapons of offence, consist of a layer of horn tissue, developed from the secretion of a vascular and nervous membrane which covers the horn-core, and forms at its base a circular pad, becoming continuous with the dermis. Both the membrane and the pad contain keratogenous tissue, hence the tissue of horns, like the wall of the horse's hoof, is derived from two sources. The portion of the horn surrounding the pad is known as the root, that covering the core the body, while the part projecting beyond the core is the point. A number of rings appear, surrounding the horn just above its root, which are rather unreliable indications of the age of the animal. In shape horns vary much ; in the bovidae, the typical form is crescentic, with the convexity turned more or less downwards and outwards ; in the ovidse, where developed horns are less general, they are usually curved spirally, some- times assuming a very graceful curve, the first bend being with the convexity outwards and forwards ; in the goat they are closer together, and more perpendicular, being slightly curved, with the convexity inwards ; all these forms are subject to great variation, some species of ruminants, as the camelidae, being altogether without horns, while in others their development is enormous. Animals possessing horns of the above type are classed as cavicornia, or hollow-horned. The horns of deer (antlers) differ from these, in being formed of solid bone, in having branches, and being deciduous, falling off every year to be replaced by new ones. The hoof is, of course, divided into two parts, one for each digit, each part resembling in shape the distal phalanx. Their general structure resembles that of the horse's hoof, but the frog is little developed. A small horny projection appears on each side of the posterior aspect of the fetlock ; these are rudimentary hoofs, each containing a small bone disconnected with the skeleton. OMNIVORA In the hog the concha is large, but variable in its arrangement, being c?ometimes erect sometimes flaccid. In connection with the eye the gland of Harder exists. The skin is thick, often destitute of pigment, and has a very RODENTIA. 553 "thick subjacent layer of fat. The amount of hair on the skin varies greatly, but appears to decrease in proportion to the domesticity of the animal, the wild boar being provided with a comparatively thick coat. The hairs are thick and strong, being commonly known as bristles.- In a general sense the hoofs resemble in form those of the ruminant, but they consist of four pieces on each extremity. See Fig. 32. CAENIVOEA. The conchal cartilage in the dog is extremely variable, both in shape and size, according to the breed, but in most breeds it folds downwards, forming the drop, or flap, which serves to protect the cavity cf the external ear from the intrusion of foreign matters. In the cat, and in fact in the felidce generally, the concha is broad, short, and erect, with the opening turned forwards. The globe of the eye is much more spherical, while the iris is of various modified shades of yellow. The pupil is circular, and the tapetum lucidum of a bluish white. In .some features the eye of the cat differs, the pupil being circular only when fully dilated ; when contracted it appears as a narrow vertical slit ; the iris has a greenish lustre, while the tapetum lucidum is golden yellow. The sudoriferous glands are extremely minute and difficult to find, excepting about the region of the nose and digital pads. The latter are callous thicken- ings of the epidermis, upon which the animal walks. The distal phalanges are covered by horn, which projects, curving outwards and downwards to form the claws. As we have already seen, the claws are retractile in the cat, where they are also sharp, and serve chiefly as weapons of ofi"ence. ' In the dog the •claws are virtually fixed and blunt, becomiug worn by constant locomotion .and scratching. No rule can be given as to the nature of the hair in dogs,. as it differs greatly in length, texture, and colour. In the cat it is short, sleek, and furry, and in colour equally variable. The touch-hairs, or whiskers, situated at the sides of the nose, are well marked in the cat, and are usually white in hue ; the tail is generally covered by hai'" nearly as short as that on the rest of the body. KODENTIA. The concha of the ear is large and very long in the rabbit, and may be either •erect or pendent, but most usually it is the former. There are no puncta lachrymalia J the lachrymal gland and membrana nic(;itans are both large. The rabbit tribe is remarkable for including a large number of albinos or individuals devoid of pigmentary tissue ; the result of this is perfect whiteness of hair and skin, apd redness of the iris, the latter being due to the thick plexus of blood-vessels contained therein, which is displayed by the absence of pigment. The claws somewhat resemble those of the dog, but they are better adapted for scraping the soil, the animal being naturally a burrower. 554 COMPARATIVE ^STHESIOLOGY. AVES. Birris have no concha, tlie external ear comprising only the auditory meatus^ This deficiency in the apparatus for collecting sound is compensated for in the- large size of the labyrinth. The cochlea is not shell-shaped, but merely a bent tube ; the semicircular canals are proportionally very large. The auditory ossicle's are represented by a single bone, called the columella, which perhaps represents the stapes, attached by processes of cartilage to the tympanic membrane. Owen considers these cartilages the representatives of the mammalian malleus, Huxley that they represent the incus, while the latte authority holds that the malleus is represented by the os quadratum. The Eustachian tube is large and osseous in structure. The eye in birds is very large, and only slightly movable. The sclerotic coat contains anteriorly a ring of imbricated osseous scales varying in number from twelve to twenty. Not unfrequently it becomes ossified posteriorly forming an osseous sheath round the optic nerve The pecten is a vascular membrane stretching from the porus opticus into the substance of the vitreous humour. The choroid coat is always black, and the pupil round ; the iris is said to contain striated muscular fibre. The membrana nictitaris is well developed, and moved by two muscles. The lachrymal and Harderian glands are present, but the Meibomian glands are wanting. The exoskeleton consists of the skin, modified in places into horn or scales, and elsewhere covered by structures peculiar to the class — the feathers or plumage ; these are chiefly of two kinds, the quill-feathers and the ciothinff feathers, the most rudimentary of the latter being known as "down." A quill- feather consists of two principal portions — the quill {calamus) and the vane (vexillum) ; the quill is continuous with the central shaft called the rachis, the two forming the stem or scapus of the feather. Projecting outwards from the stem on each side are a large number of pointed and very flexible barbs, these again bearing still smaller processes or barbules. At either end of the quill is a small opening or umbilicus, and inside the barrel is contained a pulp, which in young feathers is very vascular, the vessels entering by the proximal umbil- icus, which, along with part of the quill, is buried in a papillated follicle of the skin ; at the base of the shaft a second rudimentary shaft is usually formedy which, however, may be represented by a mere tuft of down. The smaller feathers are constructed on the same general principles ; they cover the body, the upper part of the legs, and the head, while the larger feathers and quills are confined to the wings and tail. The longest quiU-feathers are those arising from the hand, called the primaries J- those arising from the distal part of the fore-arm are the second- aries; while the tertiaries axe those which spring from the proximal part of the same. The rudimentary pollex carries some feathers which form the alula or bastard wing. The scapularies are feathers covering the scapula and humerus. The wing coverts axe rows of small feathers covering the bases of the larger ones ; they are described aa three, the greater, the lesser, and the inferior. The quill-feathers of the taU are called the redrices; they hava considerable mobility, and their bases are covered by a row of tail-coverts. AVES. 555 The skin becomes homy where it covers the rostrum or beak, and in some t)irds at the base of the same, it forms scales round the nostril ; or this part may have a naked or waxy appearance, which is known as the cere. Below the tarsal joint the extremity is usually covered with homy scales or plates, but some breeds of domesticated birds are " feathered to the ground." The pedal digits of the natatores in each limb are joined by a membrane, which is covered vnth. scaly skin, forming the wcb-foot. In the domestic fowl the claws are blunt and very strong, that bird being a good example of the order Easores, or scrafchers. The glands of the skin are few, but in many birds, and notably in aquatic species, there is a large gland in the skin of the uropygium, or basis of' the tail ; this gland seeretes an oily sebaceous fluid, which is employed by the animal in drebsing or preening its feathers. The combs or wattles^ which are the red or sometimes blue processes formed about the heads of certain birds, are very vaacular antf «iften erectile structures, appendages of the integument. CHAPTER VIIL EMBRYOLOGY. As this branch of the subject is better studied from a physiological point of view, we must refer the student to some able work on physiology for a description of the changes in, and development of, the fecundated germ of the future animal. Our few remarks, for the most part, apply to the fully, or nearly fully, developed foetal animal. As we have previously seen, the ovum is the germ of the future animal, while the fecundating principle is the spermato- zoon. From the period of fecundation to that of parturition, oi birth of the young, the interval is said to be that of utero-gesta- Hon. This interval differs in different classes of animals, but in the same class it persists with singular uniformity, the variations being small. The period of utero-gestation in the mare is 48 weeks; in the cow, 40 ; in the sheep, 21, or 22 ; in the sow, 16, or 17 ; in the bitch, 9 ; and in the rabbit, about 4 weeks. In its early stages of development the fecundated ovum is known as the embryo ; in the later stages it is called the foetus ; but the exact condition at which this change of name occurs is indeterminate. The foetus occupies the cavity of the uterus, the neck of that organ being closed during gestation by the Nabothian glands. OVUM AFTER FECUNDATION. The primary changes undergone by the fecundated ovum, interesting as they are, can be merely alluded to here. By repeated fusion of the vitelline substance there arises a cellular material called the emhryogenic tissue, or blastoderm, out of which the body of the embryo is formed. This tissue divides into three layers, an outer, a middle, and an internal, called 556 PLACENTA. 55T respectively the epiblast, mesoblast, and hypoblast. From the epiblast become developed the epidermis and its appendages, and the cerebro-spinai axis, from the hypoblast the mucous membrane of the alimentary canal, while the mesoblast gives rise to the intervening organs and tissues. A linear indentation, the primitive groove, appears on the epiblast, and below and coincident with this the notochord, which indicates the position of the vertebral column, becomes formed. The chief appendages and coverings associated with foetal life are the umbilical sac, the amnion, chorion, and allantois, the placenta, and the umbilical cord. The outer covering of the fcetus is the chorion, a membrane derived from the blastoderm and reflected over the foetus ; the placenta is formed by the connection of this covering with the mucous membrane of the uterus. The inner covering is the amnion, which contains a fluid, the liquor amnii. The allantois or urinary vesicle is regarded as taking its origin from the primitive intestine. Becoming vesicular in form to it proceed the ducts of the Wol-§ian bodies, or primordial kidneys. The umbilical sac proceeds from the blastoderm ; it covers the yelk, and like the allantois is not included in the amnion. PLACENTA. The blood of the foetus becomes purified, and charged with, the materials of nutrition, by being brought into close connection with the blood of the mother, and this process is achieved in a struc- ture called the placenta, an organ which contains capillary plexuses derived from the umbilical arteries of the foetus, and others from the uterine arteries of the mother; it is situated between the mucous membrane of the uterus and the external membranous sac, the chorion, which completely envelops the foetus, to both of which structures it is attached. The placenta assumes a variety of forms in the various classes of animals. In the mare and sow it is diffused — i.e., it consists of villi scattered over nearly the whole outer surface of the chorion, and received into crypts or correspondiug recesses in the uterine mucous membrane. In the ruminant the placental villi are collected into groups, forming a number of rounded or ovoid objects termed, cotyledons, hence this placenta is said to be polycoty- ledonary. However in the Camelidce — "The foetal villi are 558 EMBETOLOGY. scattered evenly over the chorion, so that the placenta is diffuse." (Huxley), In carnivora the villi are collected in a mass which assumes the form of a belt, surrounding the chorion, and hence called a zonary placenta. In rodentia the placenta is discoid, the villi being assembled in a more or less circular mass. The placenta is found in most orders of mammals, and in tnem alone ; its presence or absence has led to the separation of the class mammalia into a placental and an implacental division. Foetus of the Cow, with its membranes, a a, Placenta ; 6 h, Chorion with the AUantois adherent to its inner surface ; c c, Amnion seen through outer covering ; d, foetus seen through its coverings. UMBILICAL CORD. This structure is the medium of connection between the foetus and the placenta, reaching from the latter to the umbilical open- ing in the linea alba. It consists mainly of the umbilical vessels, one vein, and two arteries, and superiorly contains the urachus, a foetal tube continuous with the bladder. CIRCULATION OF THE FCETUS. 559 CIRCULATION OF THE FCETUS. In the fcEtus there is a direct communication between the right and left auricles, by the foramen ovale in the interauricular septum ; and in man the large Eustachian valve, situated at the anterior border of the posterior vena cava, at its entrance into the auricle, directs the blood from the posterior vena cava through the foramen ovale into the left auricle; as we have before remarked, the presence of this valve in quadrupeds is very doubtful. Another difference between the foetus and adult is the presence of a communicating branch between the pulmonary artery and posterior aorta, called the ductus arteriosus. There Fio. 217. Fa'.oB of the Bitch, with its membranes, a a, Uterine placenta ; 6 b. Foetal placenta ; c c, Chorion ■ d a. Amnion seen through former ; e e, Fcetna visible throcgh iU coverings. are two large arteries, the umbilical or hypogastric, which arise from the internal iliacs, pass along the sides of the bladder to its fundus, and out of the umbilical opening, being continued along the umbilic&,l cord to the placenta; in their course down the cord they wind spirally round the umbilical vein Finally, the umbilical vein leaves the placenta, passes up the cord, and enters the umbilicus, running along the floor of the abdomen, to reach the liver, where it joins the vena porta. We may now proceed to trace the course of the foetal circulation. The purified blood leaves the placenta by the umbilical vein, which is formed by the junction of numerous radical branches, and passes along the umbilical cord, accompanied by the two arteriea* 560 "EMBRYOLOGY. on entering the s.hdomcn, it passes forward along the floor of the abdominal cavity, covered by peritoneum ar.d thus arrives at the liver ; it joins the portal vein, its blood thus gaining the hepatic veins, and afterwards the posterior vena cava, where it mingles with the venous blood from the posterior region. The mixed blood is conveyed by the posterior cava into the right auricle, and passes directly through the foramen ovale into .the left auricle ; from the left auricle it enters the left ventricle, and by it is forced into the aorta ; the major part passing into the anterior aorta, is distributed to the head and fore extremities ; the remainder passes into the posterior aorta. Fio. 218. Trunk of a fuUy-develop«d foetus— opened from the left side to show the circulation, o, Um- bilical cord, cut and ligatured ; 6 b, Umbilical vein ; c. Portal vein ligatured ; d d, Posterior vena cava ; e e. Openings of hepatic veins ; /, Diaphragm cut and reflected ; g, Heart ; h. Pulmonary artery ; i, Common aorta ; i', Anterior aorta ; i" i". Posterior aorta ; k. Ductus arteriosus ; i. Left, I', Eight umbilical arteries ; m, Bladder ; n, Urachus ; o o, Thymus gland. Venous blood is returned from the anterior region to the right auricle by the anterior vena cava, and passes directly into the right ventricle along with a small portion of the blood from the posterior vena cava ; the right ventricle propels it through the pulmonary attery, from which only a small portion passes into the impervious lungs, to be returned to the left auricle by the pul- monary veins, the greater part going through the ductus arteriosus into the posterior aorta, where it becomes mixed with a portion of the blood from the left ventricle. In the posterior aorta, it flows backwards to supply the posterior extremities and abdominal viscera ; the chief portion,' however, on arriving at the termina- tion of the posterior aorta, enters the umbilical arteries, and by DEVELOPMENT OF THE FCETUS. 561 them is returned to the placenta to be purified. At birth, when respiration has been established, the placental circulation is cut ofif, the foramen ovale rapidly closes up, leaving the fossa "ovalis ; the ductus arteriosus contracts, and together with the umbilical arteries and vein, becomes obliterated. The consideration of these facts will show that the foetus is nourished by blood less perfectly arterialised than that of the adult, the blood becoming mixed in the liver, in the heart, and in the posterior aorta by means of the ductus arteriosus. It should be borne in mind that the blood which supplies the posterior regien is less pure than that supplying the head and anterior region ; this accounts for the fact that at birth the posterior parts of the frame are less developed than the anterior. Development of the Fcetus. The following facts and measurements derived from the observations of Gurlt, Leyh, Franck, and others, may be useful in determining the age of the foetus or embryo. To facilitate the study of the development of the foetus, the time which elapses between conception and birth has been divided into seven periods as follows : — I, Period. — Includes, in all the domesticated mammals, the first and second weeks after conception. The ovum lies free in the uterus. In the dog it measures about one line in length. The chorion and amnion can be made out. II. Period. — Includes, in the horse and ruminant, the 3rd and 4th weeks ; in the pig, the 3rd and half of the 4th week ; in caruivora, the 3rd week. (a) Horse. — At 28 days the embryo is p, little over | inch long. The division into head, trunk, and limbs is indicated. (6.) Ox. — At 28 days, the embryo has a length of |- inch, and corresponds in its development to the sheep's embryo of 25 days. (c.) Sheep. — Theembryo of the sheep, at 18 days, has a length of -|^ inch. At 23 days, indications of the feet appear. At 25 days, it has a length of -| inch ; indications of the eyes, ears, and tail are present ; the intestine exists as a tube connected with the umbilical vesicle ; the Wolffian body is well developed. (d.) Pig. — The pig's embryo, at 21 days, has a length 'of about J inch; at 24 days, 1 to f inch. The umbilical vesicle has, reached its maximum size. 2o 562 EMBRYOLOGY. {e.) Carnivora. — The villi appear on the chorion, and become attached to the mucous membrane of the uterus. At 18 days, the embryo of the dog has a length of about ^ inch ; the primitive groove and chorda dorsalis are present. At 19 or 20 days, the heart is present as an S-shaped tube ; the intestine begins to form. At 21 days, indication of the eyes, ears, and, "Wolffian body are present ; the limbs are present as small blunt processes. III. Period. — Includes, in the horse and ox, the 5th to the 8th week ; in the sheep and gOat, the 5th, 6th, and first half of the 7th week ; in the pig, the last half of the 4th, the 5th, and first half of the 6th week ; in carnivora, the 4th week. {«.) Hors". — The horse's embryo^ at 6 weeks, has a length of 1|- incii. At 7 weeks, 2 inches; and at 8 weeks, 2|- inches; the thoracic and abdominal cavities are closed. (6.) Ox. — At 6 weeks, the embryo is ^ inch in length, and corresponds to the 22-2 o days-old dog's embryo. At 7 weeks, it is about 1^ inch in length; the udder begins to form ; the kidneys and ureters are present. At 8 weeks, the embryo is from 2 inches to 2|- in length. (c.) Sheep. — At the 5 th week, the embryo has a length of 1 inch, and, in development, corresponds to the 25 days-old dog's embryo, (d.) Pig. — At 28 days, the embryo has a length of 1 inch. At 37 days, 2-1 inches. (e.) Carnivora. — At 22-23 days, the embryo has a length of about "I inch ; mouth-groove, nostrils, lungs, trachea, and larynx are present ; the anus is still closed ; Wolffian body well formed ; •limbs about one line in length. At 25 days, the thorax is closed, and the abdominal cavity almost closed. At 26-28 days, the embryo is about 1|^ inch in length ; all organs are more or less distinctly marked. IV. Period. — Includes, in the horse, the 9th to the IStb week; in cattle, the 9th to the 12th week; in the sheep and goat, the last half of the 7th, the 8th, and the 9th weeks; in pigs, the last half of the 6 th, the 7th, and first half of the 8th week ; in carnivora, the 5 th week. (a.) Horse. — At the 9th week, the embryo measures 3^ inches ; the external ears are very small ; the Wolffian body, genital DEVELOPMENT OF THE FffiTUS. 563 glands, kidneys, and suprarenal capsules are present. At 10 ^•eeks, the embryo measures Sf inches; the internal and external genital organs are formed. At 11 weeks, the embryo measures 4 ^ inches. At 1 2 weeks, 4|- inches ; ,and at 1 3 weeks 5|- inches. (6.) Ox. — At 9 weeks, the embryo measures almost 3^ inches. At 10 weeks, 3f inches. At 11 weeks, 4f inches, and its development corresponds to that of the horse's embryo of the same age ; mouth-groove and nostrils are closed by a thin mem- brane ; the divisions^ of the stomach are present. At 1 2 weeks, the embryo measures' 5-| inches. (c.) Sheep and Goat. — At 8 weeks, the length of the embryo is about 2 inches. At 9. weeks, 3f inches ; the nostrils are still closed. {d.) Pig, — Length of embryo in the 8th week is 3^ inches. (e.) Carnivora. — Length of embryo in the 5 th week is 2-| inches. V. Period. — Includes, in the horse, the 14th to the 22nd week; in the ox, the 13th to the 20th ; in the sheep and goat, the 10th to the 13th; in the pig, the last half of the 8th, the 4Hh, and the 10th week; in carnivora, the 6th week. (a.) Horse. — During this period the embryp increases from 5-| inches to 14f inches. At 17 weeks, the first hair appears on the lips. At 22 weeks, the lips, eyelids, and point of tail are provided with hair. (6.) Ox. — The embryo increases from of inches to 12f. At 18 weeks, the hair appears, and the testicles descend into the scrotum. (c.) Sheep and Goat. — At the end of this period the embryo measured C-f inches ; hair is still wanting. (d.) Pig. — The embryo measures 5^ inches. (e.) Carnivora. — The embryo has a length of 3-^ inches. VL Period. — Includes, in the horse, the 23rd to the 34th week; in cattle, the 21st to the 32nd week ; in the sheep and goat, from the last half of the 13th to the 18th week; in th^ pig, from the 11th to the first half of the 15th ; in the dog, the 7th and 8th weeks ; in the cat, to the end of the 7th week. (a.) Horse. — The embryo grows about one inch weekly, and ■at the end of the period has a length of about 27 inches. The 564 EMBRYOLOGY. hair appears on the crest aud back. The testicles lie near the- abdominal ring. (b.) Ox. — The embryo at the end of 32 weeks measures about 25 inches. (c.) Sheep and Goat. — The embryo has a length of from 10 to 13 inches. (d) Pig. — The embryo measures about 7 inches in length. (e.) Carnivora. — The dog's embryo measures about 5 inches ;_ the cat's embryo, 4 inches. The body is covered with hair, and the claws are present. The eyelids are closed, and the testicles are still in the abdomen. VII. Period. — Includes, in tlie horse, the 3oth to the 48th week ; in cattle, the 33rd to the 40th week; in the sheep and goat, the 19th to the 21st or 22nd week ; in the pig, the last half of the 15th to the 16th or l7th week; in dogs, the 9th week ; and in cats., the 8th week. In all animals it reaches up- to the time of birth. (a.) Horse. — The foetus attains at the end 6i this period a length of over a metre (3 feet) ; it is completely covered with hair, and the testicles pass into the scrotum. The inguinal ring- is very wide, and slight hernia is generally present. (6.) Ox. — The foetus measures atout 32 inches. (c.) Sheep. — The foetus has a length of about 18 inches. Goat. — The foettis measures about 1 3 inches ; if only one foetus is present, 18 inches. (d.) Pig. — The fostus has a length of 10 inches. (e.) Carnivora. — The foetus measures about 7 inches. The cat's foetus, about 5 inches. APPENDIX. No. I. GENERAL DIRECTIONS FOR DISSECTION. Compiled chiefly from Chauveau's " Traite d'Anatomie Comparie d£S Animaux Domestiques." THE ARTICULATIONS AND LIGAMENTS. In order to prepare the articulations, the student should select young, in pi'eference to subjects advanced in age, because in the former the density of the cellular tissue is less than in the latter As th'e ligaments are prepared with difficulty when their external surface is dried up, care should be taken to keep them protected from the air until the time to dissect them, by covering them with wet linen rags, or with the hide of the animal. It is convenient to separate the articulation which one wishes to study, by cutting the bones at a short distance from the articulatory surfaces. The handling of the piece is thus more easy, and the dissec- tion is made under more favourable conditions. It is important to take as much care as possible of the muscles which surround the ■ articulations, so as to be able to study their connections with the ligaments. If it is absolutely necessary to take away the muscles, t^eir attachments shoitld be preserved. Study first the capsular ligaments, and then remove them so as to display the funicular bands. The latter, in their turn, are to be sacrificed so as to expose, by means of difierent sections, the interosseous ligaments, if any exist. Separate at last, in a complete manner, the two articular surfaces, laying them bare, and then examine their conformation. The synovial membranes, with their difierent cul-de-sacs, being a very important subject of study with reference to the diagnosis and treatment of certain articular diseases, the student is recommended to preserve a 565 566 APPENDIX. special piece or preparation for the study of those serous membranes. He may also very easily inject their interior with plaster of Paris, or with tallow, coloured black, so as to distend their cul-de-sacs, and favour the study of theii' connections with the ligaments, tendons, or muscles. THE MUSCLES. Choice of a Svhject. — Ii a, number oi subjects are at the disposal of the student, so that he has it in his power to make a choice, he should give the preference to those in which the muscular system is well dcvelopedj avoiding however very fat animals. Subjects of small or middle size are always more convenient than those having great masses of muscle and fat. Asses and mules, when they are very lean, show the muscular system. very distinctly. Position of the Subject. — It is important to place the subject, imme- diately after death, in a convenient position, as cadaveric rigidity preserves it. Without this precaution, the different parts of the body of the animal may take an inconvenient attitude, and all attempts to rectify the position will be for some time futile, especially in animals of greac size. The subject may be placed in three different positions : — 1. The animal is placed in the first position when it is laid upon its oack, and the four extremities are raised in the air, and supported by- means of cords or ropes fixed to the pasterns and passed through movable rings, which are fixed to the extremity of four upright bars or posts at the comers of the table upon which the animal is laid. The head passes over the end of the table, and rests upon a stool, on a lower level, so that the neck may not be twisted. 2. To place the animal in the second position, it is turned upon its belly, the extremities extended upon the table, and the head supported between two upright bars, by means of a rope passed under the jaw. 3. The subject is said to be in the third position when it reposes or* its side. As far as possible the skin should not be removed, except from thosb regions which are to be dissected at the time. If it can be done, tiie student should take the precaution of wrapping up the parts with clotns wet with some preservative fluid, to prevent the drying up of the apo- neuroses and the superficial muscles. To dissect a muscle, raise the aponeurosis, or the other muscles whicJ; cover it, and dissect off the cellular tissue which enwraps it, the fat, and after ascertaining their names, the glands, vessels, and nerves lodged in the interstices. Dissect the aponeurosis in strips, making the scalpel glide APPENDIX. 567 laetween the fibrous layers, holding the blade always parallel to the sur faces. Any muscles covering it ought to be entirely cut away, by being divided near the middle, across their fibres, the two ends refiected to the side, and the study of their attachments is thus more easily made. Remove the cellular tissue by lifting it with a pair of forceps, and insert- ing the edge of the scalpel in the angle formed by the cellular tissue and the surface of the muscle. For removing fat, glands, kc, scissors may be used with great advantage.. DlSSECTIOX OF ALL THE MuSCLES UPON THE SAME SUBJECT. Place the subject in the first position, and commence the study of the muscles of the inferior abdominal region. Then cut ofi" these muscles, the one extremity from the sternal attachments, the other from the pre- pubial tendon and crural arch. The cavity of the abdomen and viscera will thus be displayed ; and the latter beii g removed, the student should proceed to study the diaphragm, internal crural region, the sublumbar region, the anterior and posterior feporal regions, as also the superficial muscles of the inferior cervical and pectoral regions. Turn the animal over, and place it in the second position. Dissect the muscles of the ears, those of the superior cervical region, the withers, the costal region, the spinal region of the back and the loins, and the region of the croup. The fore limbs may be partly prepared at the samo time, one being removed for the study of the fore-arm and foot. Afterwards, separate one hind limb by sawing the femur through the middle, and then proceed to the dissection of the muscles of the leg and hind foot. Then by means of another cut of the saw carried through the middle of the loins, isolate completely the pelvis, to make a dissection of the coccygeal muscles and the deep muscles of the internal femoral region. The animal having been turned upon its side in the third position, open the cavity of the chest and saw through the ribs near their extre- mities, thus forming two sections, the one containing the triangularis sterni, the other the inferior and lateral muscles of the head and neck. The subject may afterwards serve for the study of neai'ly all the joints. Removal of the Hoof. As the terminal insertions of some of the muscles of the limks are situated in the interior of the hoof, it is absolutely necessary, iu order to see them, to break open this horny case, and we will describe a simple method of performing this operation. The instruments necessary for breaking open the hoof are a scalpel, a chisel, a hammer, and a pair of strong forceps. The limb is fixed by one or two 568 APPENDIX. assistants holding it in a vertical position, the foot resting upon a table, stool, or solid block of wood. Push in, as deeuly as possible, the blade of the scalpel between the sensitive and the hoi'ny wall ; move it about from right to left, and make it follow the contour of the latter. By means of the cliisel and the hammer, split the wall into, four or five fragments by a convenient number of vertical incisions. When the wall has been thi." divided into several segments, detach each of these, by inserting the point of the chisel into one of the incisions, and, using this instrument as a lever, throw back the portion of horny substance to the right or left. The flap of the opposite side is then raised and separated from the subjacent tissues. Their complete detachment will be efiected by means of the strong forceps, and by twisting them with considerable force, the portion of the wall will be torn from the sole. In order to uncover the latter, pass the blade of the scalpel between the upper face of the horny arch and the sensitive sole ; push the point of the chisel into the space thus opened, raising lightly the external edge of the sole. Then seize the latter with the forceps, and detach it, as well as the frog, by a v/rench, giving the instrument a vigorous move- ment backwards and forwards, the assistants holding the limb tightly and with a force opposed to that of the operator. THE ORGANS OF DIGESTION. The Mouth. — The whole of the mouth ought to be examined by an antero-posterior and vertical section of the head. The Palate. — Separate the head from the trunk ; then saw through the ramus of the inferior maxillary bone above the angle of the jaw and the ci'own of the last molar tooth, in such a manner as to pass between the velum palati on the omj side, the base of the tongue on the other, and leave this latter organ adherent to the lower jaw. Separate the lower jaw from the upper, cutting the masseter and alveolo-labial muscles, and in this way expose the palate and the velum palati, upon which it will then be possible to execute easily the special dissection necessary for their study. For the palate, these dissections consist in raising the mucous membrane which conceals the deep venous plexus, and in the partial removal of the latter so as to see the artery and the palatine nerves. The Tongue. — 1. Make, by means of a strong saw without a back, an antero-posterior and vertical section of the head, to study the general disposition of the tongue. 2. Remove from another head the lower jaw, leaving the tongue in the maxillary space, so as to examine the external confjrmation of the organ. 3. Upon another head intended for the APPENDIX. 569 stady of the muscles, lay bare tnese structures in the following manner: — Jlemove entirely the masseter ; detach the cheek from the lower jaw and reflect the flap upon the upper ; saw through the ramus of the jaw transvercely, immediately behind, and then before the line of the molar teeth; romove and dislocate from the temporo-maxillary articulation the upper fragment of the bone, destroying the capsular ligament and the inserdlons of the pterygoid muscles ; reverse the lower fragment so as to place the line of the molar teeth below, and the inferior border of the bone above, in the bottom of the intermaxillary space ; it is sufficient, in performing this last operation, to separate the buccal mucous membrane from the mylo-hyoid muscle, proceeding from above downwards. The dissection thus made is convenient not only for the study of the muscles of the tongue, but also for the study of the deep salivary glands, the pharynx, the larynx, the guttural pouches, the perves and arteries of the head, &c. It is always well, to facilitate this dissection, to keep the jaws open by inserting a piece of wood between the incisor teeth, immediately after the death of the animal. The Velum Palati. — Study the velum palati : 1. By an antero- posterior and vertical section of the head. 2. Make the dissection described under "The Palate," and dissect off the mucous and glandular layer, so as to lay bare the fibrous membrane, and the two intrinsic muscles ; the extrinsic muscles ought to be studied with those of the pharynx. The Stomach. — In order to study the organ in its connections, it is sufficient to open the abdomen, and raise the intestinal mass, proceeding in the following manner : — The animal is placed in the first position, and slightly inclined to the left side ; make a crucial incision upon the inferior abdominal wall, or surround all this wall by a circular incision, taking care not to wound any part of the intestine ; the whole mass of the viscera is then drawn out of the abdominal cavity and brought upon the table which supports the subject , do not allow any part of this mass to slip down upon the ground, and so avoid tearing either the intestine or the parts which the student desir-^s to preserve intact in the abdominal cavity; afterwards cut the floating colon, at the point of its union with the rectum, and the duodenum, where it passes behind the great mesenteric artery ; detach the base of the caecum from the sublumbar wall by the rupture of the cellular tissue which connects this organ with the right kidney and the pancreas ; destroy the same cellular union which exists between the pancreas and the terminal extremity of the fourth part of the colon ; separate the mesentery along with the vessels contained between its folds; the intestinal mass is thus at last expelled ^rom the abdominal cavity, and a couvenient preparation is made, not 570 APPENDIX. only of the stomach, but also of the spleen, liver, pancreas, kidneys^ ureters, &c. The following is the method of turning the stomach inside out, so as to study its internal surface, and to dissect its muscular coats : — Cut out the stomach, with about three inches of the oesophagus, and six inches of the duodenum, and then proceed to wash out the interior of the organ in the following manner, — introduce a quantity of water into the stomach by fixing the duodenum to the stop-cock of a cistern ; then with the right hand relax -the stomach, holding firmly the duo- denum with the left hand to prevent the escape of the liquid. The alimentary substances contained in the viscus are thus mixed v/ith the water, and may be expelled by a little pressure made upon the stomach ; repeat this four or five times, thus completely washing the inner surface of the organ. To invert the stomach, making the external surface the internal, introduce through the duodenum a loop of iron-wire, passing out through the oesophagus ; pass through the loop a very strong waxed ligature, and then tic it securely round the oesophagus; by pulling the iron- wire passed through the pylorus, the latter will be sufficiently dilated to permit the passage of the cardiac end, and the stomach will be com- pletely inverted. By inflating it, the stomach-may be easily restored to its normal form and disposition, with this difference, that the mucous surface is external, and the serous internal. The Intestine. — The study of the intestine must be made on a special preparation ; open the infei'ior wall of the abdomen to show the organs. But as the mass which constitutes it is heavy and difficult to move, pro- ceed to expel the contents by a proceeding analagous to that described under " The Stomach." A puncture is made in tte csecum, sufficient to permit the escape of the substances accumulated in this reservoir. Those accumulated in the colon are got rid of by an incision in the pelvic flexure, those in the rectum, through an opening made in the floating colon ; the small intestine is cut into three or four nearly equal parts. This operation having been completed, inflate the intestines so as to show their normal size ; and thus the general disposition of the intestinal mass may be studied with the greatest ease in the interior of the abdomen. It will also be well to take the whole .intestine out of the body of the animal, and, placing it upon the table, isolate the different parts, study their succession, and gain a complete idea of their form. THE ORGANS OF CIRCULATION. Structure of the Heart. — Before proceeding to the dissection of the muscular fibres of the heart, it is indispensable to boil this viscus in ■water for half or three-quarters of an hour. APPENDIX-. 571 The Heart. — Place the animal in the second position ; remove the sternal ribs, separating them from their cartilages ; then dislocate the costo-vertebral articulations. This dissection permits the study of the situation and general disposition of the heart and of the pericardium. To examine with ease the l-eciprocal arrangement of these two organs,, remove them from the thoracic cavity by detaching the sternal insertion of the pericardium. Peeparation op Arteries. — The preparation of arteries consists of two successive operations — 1. Injection ; 2. Dissection. Injection of Arteries. — Injection is an operation consisting of the introduction into the interior of the vessels of a solidifiable substance,, intended to give to their canals the volume and conformation which they present during life, when they are filled with blood. Lard mixed with lamp-black is the material usually employed. Another injection some- times used consists of gelatine, mixed with a certain quantity of plaster of Paris ; but this is little used in the French school. A copper or brass syringe and a nozzle, fitted with a stop-cock upon the extremity of the syringe, is necessary for pouring the injection into the arterial vessels. The method of making a general injection is as follows : — The animal having been laid upon a table, the carotid artery is laid bare by meana of an incision made in the jugular gutter. The vessel is opened longi- tudinaUy. A ligature is applied above the opening, and the nozzle is^ securely fixed in the artery, upon the cardiac side, by aid of a second ligature. The injection, prepared beforehand, is drawn into the syiinge. The syringe is then carefully screwed upon the nozzle, and the piston is pushed steadily onwards, so as to make the injection pass into the arterial canals. The following form useful injections : — Lard, or Tallow, Oil of Turpentine, Colouring Matter, Bees'-wax, . Tallow, . Colouring Matter, 9 parts. I „ 1 part. 8 „. ad. lib. Lamp-black, Indigo, and Prussian blue may be used for the veins; for the arteries, as vermillion is expensive, Venetian red mixed with red lead is a good substitute. To succeed well in this operation, attend carefully to the following precautions : — 572 APPENDIX. Inject an animal which has been killed by bleeding, and before it is cold, and wash out the vessels with warm water, 2. Heat the injection to a degree of temperature which the finger can bear without pain. If it is colder, the lard solidifies too soon ; if it is warmer, it may shrivel up the sigmoid valves, pass into the left ventricle, thence into the auricle and pulmonary veins, an accident which is also sometimes caused by pushing the piston of the syringe with too much force. 3. Avoid applying too much force to the piston. 4. Stop the injection when the arteries react, by their elasticity, upon the piston, so as to drive it backwards. Instead of making the injection into the carotid, we may fix a long •curved nozzle into the aortic trunk itself, after having made an opening into the left side of the chest, at the level of the heart, by cutting away two segments of the ribs, and by making an incision into the pericardium over the left ventricle, so as to introduce the nozzle directly into the aorta. This proceeding allows the injection to be as hot as possible, and gives sufficiently good results, because the injection then penetrates, if it be injected under favourable conditions, almost into the capillary vessels ; and ir some organs, forces the injection even into the veins. But whichever method is followed, there are certain parts which cannot be ioached by a general injection ; thus a special operation must be performed to force the injection into the vessels of the extremities. After having separated them from the trunk, by sawing them through above the knee or the hock, they are allowed to remain for two hours in a bath of water, kept constantly at a temperature of from 60 to 70 degrees, or more, and then they are very easily injected through the posterior radial artery or the anterior tibial, or through any of the other arteries which present their open mouths upon the section of the limb. If we wish to make partial injections of other parts of the body, it may be found easier not to separate them completely from the trunk ; but then the student should take the precaution of cutting ofi" or tying the vessels which establish anastomotic communications between the arteries injected and those which he does not wish to inject. For example, if he wishes to inject the arteries of the head, it is sufficient to inject one of the two common carotids, having tied the other in the middle of the neck, and the two vertebral -arteries in the interstice between the two portions of the scalenus muscle. To inject the capillary system, recourse is had to other substances, and to a different method. The following may be used : varnish, alcohol, essence of turpentine, holding in suspension very fine colouring materials, gum arable, dissolved and coloured by any soluble colouring matter, and ijolours ground in oil, or suspended in essence of turpentine. APPENDIX. 575 Tfc is evident that the pulmonary artery will not be reached by the general injection already described. Inject it directly by passing the injection into the right side of the heart, through the anterior vena cava, after having tied the posterior vena cava. Dissection of Arteries. — There are no general rules to be given for the dissection of arteries. Injection of Veins. — It will make the study and dissection of the veins easier, to fill them with injection ; but to do this, a difierent pro- ceeding is followed from that described for arteries. In place of making the injection flow from the trunks towards the branches, as in arteries, it must flow Jrom the branches to the trunks in the case of the veins, owing to the presence of the valves. Four injections are in general sufficient to fill the whole venous system in a satisfactory manner : the first is poured through the alveolar vein under the masseter muscle: the second into a digital vein of one or two fore-limbs, on the side of the foot, after having destroyed with a stylette the several valves which are sometimes found near the point of union of the roots of this vein, from the cardiac side ; the third into a posterior digital vein ; the fourth into an intestinal vein. If any important veins require tn be studied after these four operations, they are separately injected. THE LYMPHATIC SYSTEM. The lymphatic plexuses are studied after having being injected with mercury, a proceeding which may be very briefly described, as it is seldom done by those for whom this work is intended. The apparatus commonly used consists of a tube of glass, continued by a flexible tube, which carries at its lower end an iron stopcock and a fine cannula made of iron or glass. To use this apparatus, fill the tube with mercury and suspend it ; grasp the cannula with the right hand, holding it parallel to the membrane which is to be injected, and push it into the superficial layer of this membrane. The extremity of the cannula is thus intro- duced into the middle of the meshes of the plexus, and of course wounds one of the small vessels which compose it ; then turning the stopcock, permit the mercury to flow into the vessels through the jiuncture. In this way they may be perfectly filled. The lymphatic plexuses being always placed above sanguineous ones, always take the precaution of puncturing the membrane as superficially as possible, because if the point of the cannula penetrate too deeply, the mercury passes into the veins, and the operation is a failure. The study of the branches and trunks of the lymphatics may also be facilitated by inflating them from their origin to their termination. If 574 APPENDIX. ■well done, this proceeding, which was almost exclusively followed by the ancient anatomists, gives very satisfactory results. It is sxifficient to demonstrate the texture of the glands. The Thoracic Duct. — Ligature the jugular and brachial veins near their termination, as also the anterior vena cava about its middle ; lay bare the thoracic duct by cutting the right ribs ; open it near the pillars of the diaphragm, and pour into it two injections of lard, the one before and the other behind the incision. The first injection will fill the duct along •with the venous reservoir, which is intercepted by the ligatures applied to the vessels, as already described ; the second, since it is directed in the opposite direction to the valves, overcomes the resistance ofiered by them, and expands the canal of Pecquet and the chief branches which end in it. Another method is as follows : — One of the branches in the abdominal cavity may be selected, as, for example, one of those united to the colic arteries, near their origin, and the thoracic duct completely injected from its origin to its termination. But this operation requires more practical dexterity than the first, in order to reach the vessel into which the nozzle is to be inserted ; and it is not at all easy to perform it upon fat animals. THE NERVOUS SYSTEM. The Braijst. — To study the brain, it is first removed from the cranial cavity. This is done by two operations. The first consists of opening the cranium by removing its vault, using a saw, a chisel, and a hammer, after having first removed all the parts covering it. Then open the dura mater with the scissors, and expose the brain, which is to be removed by raising its posterior extremity, and cutting from behind forwards all the nerves issuing from its base, with the pituitary gland, as far forwards as the end of the olfactory lobes. This operation is quickly performed, but it does not permit of the preservation of the pituitary gland, which is strongly fixed in the sella turcica, an inconvenience avoided by employ- ing the following method of opening the cranium at the base. After having separated the head from the trunk, remove the inferior maxilla, the tongue, the hyoid bone, and lay bare the osseous surface, cutting away all the soft parts. The head thus prepared is held by an assistant, the cranial vault being laid upon the table or a block of wood. The operator divides the zygomatic arches and the styloid processes of the occipital ; then divides in succession the condyles of the same bone, the basilar process, the sphenoid, the palatines, the ethmoid ; and returns to the lateral parts, which he cuts through successively from the occipital to the ethmoid. The brain having been thus sufficiently exposed, the dura. APPENDIX. 575 •mater is set free as in the first operation, and raising it with the left hand, the adhesions by which it is yet fixed to the vault of the cranium, adhesions chiefly composed of the veins of the brain, which disgorge themselves into the sinuses of the dura mater, are divided by the scissors held in the right hand. Break down the adhesion in the ethmoidal fossa with the point of the scalpel, detach the olfactory lobes, and the mass of the brain is then set quite free. This proceeding is an operation more difficult than the first, but it has many advantages, preserving intact not only the pituitary gland, but also th^ ethmoidal lobes ; and the ganglia of the cranial nerves are exposed as distinctly as the nerves themselves. Having thus described the means of removing the brain from its osseous cavity, it is enough to state here that in order to study its structure with advantage, it will be well to have two brains, hardened by soaking for a week or more in alcohol, or in water having a little nitric acid added to it (1 to 20), so as to contract the nervous substance, and make more apparent the outline of the cavities of the brain. No. II. ON A SUPERNUMERARY OBLIQUE MUSCLE OF THE EYEBALL. By Thomas Strangeways, Professor op Veterinary Anatomy, Edinburgh. {Journal of Anatomy and Fhynology, second series, No. II., May, 1868.) A FEW days ago, when dissecting the muscles of the eyeball of an ass, in the dissecting room of the Veterinary College, I was somewhat astonished at finding a small but well-defined muscle, situated between the superior and inferior oblique muscles. It originated by a delicate tendon from a minute depression, in the superior part of the orbital plate of the frontal bone, about midway between the origin of the inferior oblique and the loop or pulley through which the belly of the superior oblique passes. The tendon of origin was succeeded by a fusiform fleshy belly of about three lines in diameter, and about an inch in length, which passed obliquely upwards and outwards on the outer side of the external rectus. The belly, embedded in a quantity of adipose tissue, terminated in a thin, flat tendon, which, after running nearly parallel for a short distance witii, and loosely attached by cellular 576 * APPENDIX. tissue to, the upper part of the belly of the superior oblique, became blended with the tendon of insertion of that muscle just as it passed under the tendon of insertion of the superior rectus. As there are some slight differences between the arrangements of the oblique muscles of the eyeball of the Equidae and those of Man, it may be necessary to point these out, so as to prevent any misunderstandings as to the position of this small obliqu-e muscle. The superior oblique muscle in the horse and ass is — \st, Relatively longer and larger than in man, and is fleshy for some distance after it has passed through the loop, which loop is situated at the base of the orbital process of the frontal bone ; 2nd, The muscle, after passing through the loop, extends almost directly outwards under the tendon of the superior rectus, to gain its insertion between the tendons o£ insertion of the superior and external recti. The point of insertion is thus not so near to the back of the eyeball as in man. The inferior oblique, arising from the lachrymal fossa, is directed forwards and upwards, its belly running in the same direction as the reflected portion of the supeiior oblique, and becomes finally inserted between the tendons of insertion of the external and inferior recti, much lower down and also farther forwards than in man. So far as my researches have gone, this small muscle has not hitherto been described, either in consequence of being an exceptional occurrence in this animal, or of having been overlooked. There can be no doubt^ I think, of its being an accessory or check muscle of the superior oblique, placed there for the purpose of preventing the belly of that muscle becoming fixed in the loop through which it has to pass at such an acute angle, in the lower animals more especially. Unfortunately, the other eyeball had been removed by one of the students, to whom the subject belonged, before I had commenced my dissections ; but still, on searching within the orbit, I was enabled to find part of the belly and the tendon of origin of a similar muscle, which had precisely the same point of origin, and in all probability, a similar insertion.* * (Since the abave was published, Dr. Johnston has dissected the muscle in both, eyes of two subjects. — Ist Edition.) APPENDIX. 577 No. III. . ON A NON-STRIPED MUSCLE CONNECTED WITH THE OKBITAL PERIOSTECJM OF MAN AND MAMMALS. By Wm. Turner, M.B. (Lond.), F.R.S.E., Professor op Anatomy, University of Edinburgh. (Natural History Beview, January, 1862.) "Whilst engaged in making a dissection, in the human subject, during the winter session of last year, of the superior maxillary, or second division of the fifth cranial nerve, my attention was attracted to a pale- reddish, soft mass, filling up the narrow chink of the spheno-m axillary fissure, and extending, from the sphenoidal fissure in the sphenoid bone to the infra-orbital canal in the superior maxillary bone. It was evidently connected to the superior (ocular) aspect of the periosteum of the orbit, and i'o was pierced by the orbital branch of the cuperior maxillary nerve, from which, as well as from the ascending branches of the spheno-palatine ganglion, it appeared to receive its supply of nerves. It completely chut off the superior maxillary nerve, with its infra-orbital continuation, from the cavity of the orbit Since the period of ma,king the above observation, I have availed myself of several opportunities of examining the same region in other subjects, and have constantly observed appearances of a nature similar to those just described The amount of the reddish mass, and the depth of its tint, varied slightly in difierent instances. Frequently, it was so pale as scarcely to attract attention, which may perhaps be the reason why it has so long been neglected by anatomists. When carefully examined with the naked eye, or, still better, with a single lens, it was seen to exhibit a fibrous appearance. A small portion snipped ofi'with scissors, teazed out with needles, and placed on the stage of the micro- scope,' under' a quarter-inch objective, was observed to be composed of pale, flattened, band-like fibres, having a faintly granular aspect, and presenting indications of elongated nuclei at intervals. From these characters I had little doubt that the structure in question consisted of the non-striped form of muscular fibre. As considerable difficulty is always experienced in obtaining for examination the contents of the human orbit, in a perfectly fresh con- dition, I, in the next instance, proceeded to dissect the orbits of some of the more readily obtained mammals, with a view of ascertaining if a 2 P 578 APPENDIX. similar structure existed in them. In the orbit of the sheep I have most satisfactorily observed appearances which have fully confirmed the opinion of the structure already expressed. The orbit of this animal difiers from that of man in possessing much less perfect walls. As a consequence of this, the orbital membrane, or periosteum, is a structure of much importance, for it stretches across the floor of the orbit from its outer to its inner wall, extends backwards to the optic foramen, and completes the boundary of the cavity at the spot where the bony wall is wanting. If the contents of the orbit be carefully removed, and the orbital membrane examined from above, it will be seen to be a well-defined structure distinctly fibrous, and in many places having an almost tendinous-like aspect. Intimately connected with, and forming an essential part of it, is a thin layer of a pale reddish substance, which extends across the greater part of the floor of the orbit, passing back- wards to the optic foramen and sphenoidal fissure. In close contact with this structure, especially at the posterior part of the orbit, is a well-marked vascular network, suflSciently injected with blood to be distinctly visible. This vascular plexus constitutes a small rete mirabile, connected with the ophthalmic artery. By removing a small portion of the reddish mass, teazing it out with- needles under water, and examin- ing it with a quarter-inch objective, it may be seen to be composed for the most part of flat, pale, non-striped fibres, collected together in bundles, having a faintly granular aspect, and exhibiting decided indica- tions of nuclei in their interior. These bundles of flat fibres are mingled with ordinary fibrous tissue, both white and yellow, the latter becoming more distinct after the addition of acetic acid. The pale, non-striped fibres have all the characters of the involuntary muscular fibre. Being desirous, however, of ascertaining if these fibres could be resolved into their constituent fibre-cells, I adopted the plan which has been recom- mended by Reichert, and macerated a portion of the orbital membrane for forty--eight hours in dilute hydro-chloric acid. I then found that, by the aid of a very slight dissection, the fibres readily resolve themselves into the elongated fusiform cells of which they were composed. In no tissue which I ever examined, consisting of the non-striped muscle, have I succeeded in obtaining more beautiful and more perfect specimens of the contractile fibre-cell than in this muscle of the orbital membrane. The fusiform shape of the cells, their size, and the elongated rod-like nucleus in the centre of each cell, gave to the texture a most character- istic appearance, I may also mention, that when the orbital muscle in the sheep was examined without the addition of any re-agent, besides distilled water, a number of elongated rod-like nuclei were always met APPENDIX. 579 -with, lying free in the water surrounding the preparation, which had evidently been loosened and detached during the dissection with the needles. These nuclei corresponded in their characters to those met with in the interior of the fibro-cells. The characters which I have now enumerated render the muscular nature of the reddish texture connected with the orbital membrane sufficiently clear. On referring to the authorities who have written on the structure of -the orbital membrane, I find that the following opinions have been expressed concerning it : — Bmdz, in a paper *' On the Orbital Membrane in the Domestic Mam- mals," describes it as distinctly fibrous, but possessing a considerable ■quantity of a yellowish tissue, which he considers to be elastic, interpo- lated with it. He regards the opinion, which had been previously advanced by Gurlt, that the tissue was muscular, to be erroneous. Stannius states that in those animals, in which the bony wall of the orbit is incomplete, the separation between the orbital cavity and the temporal fossa is mostly efiected by a fibrous membrane, containing also abundant elastic tissue. He states that Rudolphi regarded these elastic fibres to be muscular in bears, and that Meckel described a muscle in the orbital membrane of Ornithorynchus. Chauveau speaks of the fibrous membrane which completes the cavity of the orbit as entirely composed of white inextensile fibres. Gurlt considers it to be a strong fibrous membrane, with yellow elastic fibres interpolated. E. Miiller, in a very brief communication, states that he has found flat muscular fibres in the inferior orbital fissure in man, and corresponding structures con- nected to the membrana orbitalis of mammalia. It was supposed by those who held that the membrana orbitalis was a highly elastic and not a muscular structure, that it was through its elastic recoil that the eyeball was reprotruded in those animals which retracted the ball through the contraction of a retractor muscle, ff. Miiller, again, who speaks more positively than any who have preceded him, not only of the existence of a muscle, but also of the kind of fibre of which it is composed, considers that it antagonises those muscles which retract the eyeball into the socket, and that thus, the reprotrusion of the globe is produced, not by a mere elastic recoil but by a muscular contraction. If this hypothesis be correct, an arrangement exists in this locality, which is certainly to be regarded as an unusual one — viz., an involun- tary muscle acting as a direct antagonist to a voluntary muscle. Whether the hypothesis be correct or not, I am disposed to consider that the muscle has some especial relation to the vascular arrangements in the orbit. Its extension backwards to the foramina through which the 580 APPENDIX. orbital vessels proceed, and with -wliich it is in immediate relation, and the very abundant vascular network found in connection with it, point, I think, to some special relation between the muscle and the vessels, a relation which is not at all- inconsistent with what is known of the function of non-striped muscle in other localities. ****** Note. — Since the above paper was in type, my attention has been directed, by Professor Huxley, to a communication by H. Miiller, dated 15th Dec. 1860, entitled " On the Influence of the Sympathetic upon some Muscles, and on the extensive occurrence of Unstriped Muscles in the Skin in the Mammalia." As this paper throws some additional light upon the probable action of the orbital muscle, I append a short abstract of it : — H. Miiller, after referring to the many puzzling questions which have arisen respecting the function of the sympathetic nerve, and its relations to the muscles supplied by it, proceeds to ask two questions — \st, Whether, and which, unstriped muscles are supplied by other nerves than the sympathetic 1 2nd, Whether, and which, transversely-striped muscles are under the influence of the sympathetic ? In answer to the first, the action of the oculo-motor nerve upon the unstriped fibres of the iris cannot be doubted : the vagus also acts upon unstriped muscles, and the experiments of Schiff have shown that the greater part of the vascular nerves are not connected with the sympa- thetic. The second question may be most efi"ectively answered by considering the efiect produced upon the eyeball by division or irritation of the cervical sympathetic. Miiller, for this purpose, refers to the experiments of Bernard, R. Wagner, and Brown-Sequard ; the general tendency of which is to show, that division of the cervical sympathetic produces narrowing of the palpebral fissure, retraction of the bulb, projection of the nictitating membrane and narrowing of the anterior nares and the mouth. Irritation of the nerve by galvanisation, on the other hand, produces increase of the opening of the lids, projection of the bulb re- traction of the nictitating membrane, relaxation of several facial muscles. Respecting the causes which produced these changes there was some diflference of opinion. R. Wagner could scarcely conceive that any force, save the contraction of the two obliqui, could produce projection of the eyeball, and yet he asks, " How could these transversely-striped muscles receive excito-motory fibres from the sympathetic]" Brown-Sequard, again, considered that retraction of the bulb, after section of the nerve, was produced by the active contraction of the retractor and recti, and APPENDIX. 581 "tLat its projection by subsequent irritation was a reposition. Schiff Tegarded the projection of the bulb as due to the action of the obliqui : the movements of the lids he considered to be passive, and due to those of the bulb. Remak on the othef hand, believed that the narrowing of the palpe- bral fissure was due to a relaxation of the levator palpebres superioris, accompanied by a spasmodic contraction of the orbicularis. Moreover, he conceived that the sympathetic acted upon the voluntary muscles of the lids about the eye, Muller considers that it is now no longer necessary to discuss the various probabilities respecting the influence of the syn^pathetic upon the voluntary muscles of the eye, as a complete series of unstriped musc'es have now been observed, which will serve as a foundation for explaining i;he movements in question. These muscles consist of three divisions — 1st, In the orbital cavity cf mammals, a membrane (membrana orbitalis), consisting of unstriped muscles with elastic tendons, exists, which, by irritation of the cervical sympathetic, projects the contents of the orbit, especially the bulb, forwards. Retraction is produced by the transversely-striped retractor. In man, the orbital muscle is much reduced in size, and the retractor is wanting, so that a distinct projection of the bulb does not follow irritation of the sympathetic, as Wagner and H, Muller himself have observed, 2nd, The projection of the nictitating membrane in mammals is mostly due to the retractor bulbi under the influence of the N". abducens. Its withdrawal depends on some unstriped muscles which are under the influence of the sympathetic. In hares, however, the withdrawal is due to a transversely-striped muscle, which is nou supplied by the sympa- thetic but by the oculo-motorius. In man, the lid aiid its muscles are rudimentary. 3rd, The upper and lower lid possess in man, and in very many mammals, unstriped muscles, which have the power cf drawing them back. They are more feeble in the upper than the lower lid, so that by irritation of the sympathetic the latter is drawn back in a more marked manner than the former. Narrowing of the palpebral fissure, after section of the cervical sympathetic, depends upon relaxation of these muscles. Yet recession of the eyeball may depend ■ upon relaxa- tion of the orbital muscle. Miiller, then, concludes that the movements occasioned by experimenting on the cervical sympathetic are not such as to entitle us to infer an inflnence of that nerve upon voluntary striped muscle. He also considers that the movements about the nose and mouth, said by Bernard to be produced by section of the sympathetic, 682 APPENDIX. if they do take place, are owing to the presence of unstriped cutaneous muscles. Muller next inquires into the existence of unstriped muscles in the skin of the ear. He has occasionally found, on galvanising the cervical sympathetic in cats, that a movement of the hairs growing upon the skin at the entrance of the concha has taken place. This experiment has, however, frequently failed both in cats and other animals. A careful examination of the skin of the part did not give any indications of unstriped muscles, but very distinct muscles were seen connected to the hair follicles. He considers these experiments of interest, as they appear to indicate whence the muscles of the hair follicles receive their nerves. Owing to the movement of the hairs being limited to a very small locality, during the irritation of the sympathetic, one must suppose that only a very small part of the unstriped muscular apparatus of the skin of the cat can be regulated by the cervical sympathetic. IISTDEX ABDOMEN: 300. regions of, 300. Abdominal rings, 203. tunic, '200. Abducens nerve, 497. Accessory organs ot digesJion.|U^.^_ ^^^^ in Kuminants, 373. Acervulus cerebri, 484. Acetaliuluiu, h7. Adipose tissue, 123. ^stliesiology, 525. comparative, 552. Air cells, 339. Albinos in Rodentia, 553. Alimentary canal, 275. AUantois, 557. Alula, 554. . Alveoli canine, 58, 63 incisor, 58, 63. molar, 57. 63. Amnion, 557. . Amphiarthrosis, 127. Amptiioxus, 4. Ampnllse, 530. Analogy, 6.. Anapopbysis, 112. Anaioiny. animal, 1. comparative, 1. descrii)live, 6. , . , distinguished from physiology, 2. divisions of, 6. minute, 2. morbid. 2. practical, 2. special, 1. surgical, 2. transcendental, l. veterinary, 2. Andersch's ganglion, 499. Angiology, 387. comparative, 458. Annular cartilage, .'^26. ligaments, 124. Anterior aorta. 418. in Omnivora, 461. in Ruminants, 459. nares, 42. vena cava, 442. Anus, 311. Aorta anterior, 418. common, 40]. in aves, 463. posterior, 402. . Aponeurotic tendons and fascia, 159. Apophysis. 16. Appendages of the eye, 5J». Appendicular joints, f^-^^^^.^^^^^ ^,3. in Omnivora, 153. in Ruminantia, 152. Appendicular skeleton, 65._ of Dog, 112. of Hog. 108. of Rodent, 115. of Ruminant, 103. Appendix I,, 565. II., 575. III., 577. Aaueduct, 14. of Sylvius, 483. of Fallopius- 51. of vestibule, ^l. 531. Aqueous humour, 536. Arachnoid membrane, 4C9. Arbor vitte, 476. uterinus, 361. Arch, crural, 202. hfemal, 23. neural, 21. palatine, 38, 60. pectoral, 66. pelvic, 83. radio-ulnar, 70. tibial, 93. zygomatic, 40. Arcuate ligaments, 209. Arnold's ganglion, 516. Arrangement of fascite, 252. Arteries, 3>i8. structure of, 399. augulaiof eye, 427. anterior abdominal, 420. antei iiir aorta, 418. anterior auricular, 430. atiterioi- cerebellar, 486. anterior cerebral, 487. anterior choroid, 488. anteiior communicating, 488. auieriiir deeu temporal, 432. anterior radial, 422. anterior tibial, 416. arteria .'entrails retinae. 432, 536. arteria humeralis profunda, 422. arteria pedis perforans, 416. arteria profunda femoris, 414. arteria superflcialis femoris, 414. asternal, 420. basilar, 486. brachial. 418. brachio-cephalic, 418, 463. broncho-oesophageal, 404. buccal, 433. cardiac, 40i. carotid, 424. carpal arch, inferior, 423. carpal arch, .superior, 422. centralis retina;, 4J2. cephalic, 424. cerebral, 486. cerebro-spinal. 426, 486. ciliary. 4'ti. 584 Arteries, circle of Willis. 487. circulu.s arteriosus, 418. circumflex, 418. circumflex, ilii. 412. coccygeal, 4ii. coeliac axis, 404. colic, 407. common aorta, 401. common carotid. 418, 424. coraco-radial, 422. coronary, 401. cubital, or ulnar, 422. digital, 417, 424. dorsal, 419. dorsal nasal, 427. dorsal of penis, 413. duodenal, 406. epigastric. 412. ext -rnal carotid. 427. external iliac, 4il. external thoracic, 421. external plantar, 415. external pudic, 413. femoral, 412. femoro-popliteal, 414. gastric, 404. gastro-epiploic, 405, 406. glosso-facial, 427. gluteal, 411. great meningeal, 431. great mesenteric, 407. great matatarsal, 416. hEemorrhoidal, 407. hepatic, 405. humeral, 422. humeralis profunda, 422. hypogastric, 559. iliaeo-femoral, 411. ilio-lumbar, 411. ilio-esecal, 411. inferior cervical. 420. inferior circumflex, 418. inferior dental. 431. inferior labial or coronary, 429. intercostal, 403- internal carotid, 426, -IST. internal iliac. 409. internal maxillary, 431. internal plantar, 415. internal pudic, 410. internal thoracic, 420. interosseous of fore-arm, 423. interosseous palmars. 424. interosseous plantars, 415. ischiatic, 4ii. lachrymal, 432. lateral laminal, 417. large metacarpal, 424. lateral nasal, 427, 432. lateral sacral, 4ii. lesser mesenteric, 407. lingual, 428. lumbar, 403. mammary, 413. masseter, "430. mastoid. 426. maxillo- muscular, 429. meningeal, 432. middle cerebral. 488. middle sacral, 404. middle spinal, 426. 486. musculo occipital. 426. nutrient humeral, 422. nutrient radial, 423. nutrient scapular, 421. obturator. 411. occipital, 425. of the bulb, 410. of the cord, 409. of fore-limb Carnivora, 462. of the Frog, 417. onhthalmic, 432. Arteries, orbital, 433. palatine, 433. palato-labial, 433. l)crforating pedal, 416. peroneal, 416. perpendicular, 417. pharyngeal or ascending pharyn- geal, 428. phrenic, 403. plantar, 415 plantar ungual, 418, popliteal, 414. posterior abdominal, 412. posterior aorta, 402. posterior auricular, 430. posterior cerebellar, 4.86. posterior cerebral. 486. posterioi circumflex, 421. posterior communicating, 487, posterior deep temporal, 431. posterior masseter. 430. posterior radial, 423. posterior tibial, 415. prehumeral, 422. preseapulai», 421. preplantar ungual, 417. prepubian, 412. prevertebral, 426. profunda femoris, 414. pterygoid-fasciculus, 431. pterygoidean, 430. pulinonary, 400. pyloric, 406. radio palmar. 423. ramus anastomoticus, 426< ranine, 428. recurrent radial, 423. renal, 408. sapheuic. 414. scapulo-humeral, 421. sesamoidean arch. 416. small metacarpal, 423. small muscular, 414. small testicular, 409. solar, 418. spermatic, 408. spheno-spinal, 431. spheno-palatine, 433. spiral, 422. splenic. 405. staphyline, 433. subcutaneous abdominal, 418, subcostal, 419 sublingual, 428. submaxillary, 427, subscapular, 421- subzygomatic, 430. superficial temporal, 430. superflcialus femoris, 414. superior cervical. 420. superior dental, 433. superior labial or coronary, 489. supraorbital, 432. thyroid, 425. thyro-laryngeal, 425. transverse, 417. transver.se facial, 430. tympanic, 431, ulnar. 422. umbilical, 409, 559. uterine. 409. utero-ovarian, 409. vaginal, 4ii. vertebral, 420. vesico- prostatic, 410. Arthrology, 120. comparative, 151. Articular cartilage, 121. depressions, 15. eminences, 14. facet. 15. head, 14. INDEX. 585 Articulations, atlo-axoid, 131. chondro-eostal, 133. coccypeal 132. commor vertebral, 129. costo- sterna) 133. costovertebral 132. distal intarohalangeal, 142. femoro-pe'vi" 145, femoro-tibial, 146. humero-radial 136. ischio-pubic (symphysis), 145. metacarpal 140. metacarpo-phalangeal, 140. occipito-atloid 131. of appendicular skeleton, 136. of axial skeleton, 129. of axial skeleton in Eumi- nantia, 151. of carpus, 137. of hyoid series. 135. of pectoral limb. 136. of pelvic limb, 143. of skull. 134. pectoral limb in Ruminantia, 152. pelvic limb in Euminantia, 152. proximal interphalangeal,l42. radio-ulnar, 137. sacro-iliac, 143. sacro-lumbar. 132. scapulohumeral. 136. special vertebral, 131. sternal, 134. tarsal, 149. temporo-maxillary, 134. tibiofibular, 148. thoracic, 132. Astragalus, 93. Atlas, 26. Atlo-axoid articulation, 131. , ^ space, 28. tudltory bulla. 51. ossicles, 527. ossicles in Aves, 554. Aves, 6. skeleton of, 115. *iixial joints in Carnivora, 153. Omnivora, 163. , , , „ Ruminantia. 151. -Vxial Skeleton, 21. articulations of, 129. Carnivora, 109. Omnivora, 105. Rodentia, 114. Ruminantia, 98. Axis, 27. BaBBS, 664. Bars of the hoof, 645. of the mouth, 63. Base of the brain, 477. easement membrane, 272. Bastard wing, 554. Bellini, tubes of, 343. Bicipital groove, 69. Bilateral symmetry, 19. Bile, 317. Biology, 1. Birds, characteristics of, 6. eye in, 554. muscles, 269. pectoral arch, 117. sketeton in, 116. Bladder, 344. Blastoderm, 666. Blood, 387. in Aves, 463. Blood-Vascular System, 387, Bones, canaliouli of, 10. cannon^ 77. cardiac. 1O6. Bones, classes of, 12. coffin, 81. contents of, 12. covering of, 11, cranial. 45. cubo-cuceiform, 104. cuneiform of tarsus. 95, 96, 97. density of, 8. development of, 16. diploe of, 11. ethmoid, 64. facial, 54, flat, 13. frontal, 48. hyoid, 64. inferior maxillary, 62. innominate. 84. irregular, 13. lachrymal, 59. lacunae of, 9. large metacarpal, 77. large pastern, 80. large sesamoid. 80. long, 12. lymphatics in, 12. malar, 68. malleolar, 104. metacarpal, 77. metatarsal, 97. minute structure of, 9. nasal, 54. navicular. 83. neck of, 15. nutrient foramina of, 12. occipital, 45. of carpus. 72, of digit, 79. of hind limb, 88. of penis in c arnivora. 114, of Ruminant skull, 98. of tarsus, 93. palatine, 59. parietal, 47. petrosal, 50. pisiform, 77. pneumatic, 119. premaxillary, 67. Pterygoid, 60. quadrate, 117. , quadrato-jugal, 117. small pastern, 81. small sesamoid, 83. sphenoid, 52. splint. 78. squamosal, 49. stifle. 91. structure of, 7. superior maxillary, 66. surfaces of, 14. temporal, 49. turbinated, 61. unciform, 76. vessels of, 12. Vomer, 61. Wormian, 48. Bowman, capsules of, 342. Brachial arteries, branches of, 4i9. Brain, 473. arterial circulation of, 486. in Aves, 524. in Carnivora, 523. in Omnivora, 623. in Rodentia. 624. in Ruminants, 522. meninges of. 469. removal of, 674. sand, 484. venous circulation of, 488. Branches of jugular vein, 447. Broad ligaments of uterus, 323. ligament of bladder, 346. of coffln-joint, 143. 586 INDEX. Broad ligament of digrit. Hi. ' of liyer, 314. Bronchial tubes, 335. Bronchi, 335. Bursae mucosae, 125. synovial, 125. Cxcvii. 307. Calamus, 564. scriptorius, 476. Calcaneo-cuboid ligament, 150. Calcaneum, 94. Calvarium, 37- ^anal. 14. alimentary, 275. Haversian, 9. , inguinal, 203. lachrymal, 56, 59. neural, 3, 21. of Gartner, 376. of Petit, 536. €analiculi of bone, 10. Cancellated tissue^ 10. Cannon bone, 77. €anthi, 538. Capillaries, 400. Capsular ligaments, 124. Capsule of the lens, 537. Cardiac bones, 105, 468. Cariniform cartilage, 36. Carnivora, bone of penis, 114. characteristics of, 6. clavicle in, 113. joints in, 153. skeleton in. 109. tapetum lucidum in, 653. Carotid artery, 424. in Carnivora, 462. in Omnivora. 461. Carpal cuneiform bone, 74. joint, 137 bones, 72. Cartilage, 120. articular, 121. cariniform, 36. cellular, 122. ensiform, 86. flbro-, 121. glenoid, 142. hyaline, 121. lateral, 549. of ear, 626. semilunar, 147. tarsal, 539. temporary, 15. xiphoid, 36. Carunculae myrtiformes, 362. lachrymales, 540. "Cat hairs," 544. Cauda equina. 471. Cavernous sinuses, 489. Cavicomia, 4. Cavities, cotyloid, i5. glenoid. 15. in the skull, 42. Cells, air. 339. giant, 12. osteoblastic, 17. Cellular cartilage, 122. Centrum ovale majus and minus, 479, C«re. 555. Cerebellum, 475. Cerebral commissures, 483. convolutions, 477. lobes. 477. sulci, 477. Cerebrospinal system, 468. Cerebrum, 476. Cereminous glands, 526. Cervical fascia, 253. nerves, 503. vertebrae, general features. 23. Cervical vertebrae, special, 26, the two last, 28. Chambers of the eye, ."136. Characteristics of Aves, 5. of Carnivora, 5. of Equidae. 4. of Omnivora. 5. of Rodentia, 5- of Ruminantia, 6. of vertebrata, 3. Chataignes,"543. Check ligament, 227, 228. Cheeks, 276. Chondro-costal articulation, 133. Chorion. 657. Choroid coat, 534. plexus, 482. Chyle, 45). Ciliary muscle, 534. processes, 635. zone, 536. Ciliated epithelium, 271. Circle of Willis, 487. Circulation, 397. in foetus, 559, in lower animals, 463. Classes of bones, 12, of joints, 126. Classification of muscles, 161. Clavicle, 66. in Carnivora. 113. ^, ^ , in Aves, 117. Cleft of Frog, 547. Clitoris, 362. Cloaca, 384. Coccygeal articulations, 132. nerves, 485. vertebrae, 32. Coccyx, 32. Cochlea, 530. Coeliac axis in Carnivora, 461. in Ruminants, 468, Cofnn bone, 81. jo-'nt, 142. Colon, floating, 3lo. great 308. Column vertebral, 21. Columnar epithelium, 271. Commissures of the cord, 472. of Frog 548. optic, 478. 492. Common aorta, 401. carpal ligaments, 139. tarsal ligaments, 149. vertebral articulations, 129. vertebral ligaments, 129. Compact tissue, 9. Comparative Anatomy, 1. .SIsthesiology— Aves, 554. Carnivora, 563. Omnivora, 552. Rodentia, 653. Ruminantia, 652. Angiology— Aves. 462. Carnivora, 461. lower animals, 463. Omnivora, 460. Rodentia, 462. Ruminantia, 463. Anthrology— Carnivora, 163. Omnivora, 153. Ruminantia. 15t Myology— Aves, 269. Carnivora, 265. Omnivora, 263, Rodentia, 268. Ruminantia, 260. Neurology— Aves, 524. Carnivora, 623. Omnivora, 623. Rodentia, 524. Buminantia, ;>22. INDEX. 587 Comparative Osteology— Aves, 115. Carnivora 109. Omnivora, 105. Rodentia, lu. Buminantia. 98. Splanchnology— A ves, 381. Carnivora, 380. Omnivora. 377. Rodentia, 383. Ruminantla, 365. conclia, 525. Oonchal cartilage. 526. Conduit, lachrymal, 56. parieto-temporal, 42, 50. Vidian, 62, 60. Condyles, 14. Cofluent, parieto-temporal, 489. subsphenoidal, 489. Conjunctiva, 639. Connective tissue, 122. Contents of bone, 12. Conus medullaris. 471. Coracoid apophysis, 66. Corlum, 542. Cornea, 533. Corona glandis, ^5. tubulorum, 306. Coronary arteries, 40l. band. 551. Coronoid process, 63, Corpora, genlculata, 483. nigra, 635. Quadrigemina, 484. Corpus albicans, 47S. callosum, 479. flmbrlatum, 481. Highmorianum, 349. luteum, 368. striatum, 481. Costo-sternal artriculation, 133. Costo-vertebral articulation, 133. Cotyloid cavity, 15, notch, 87. Covering of Bone, 11. " Cow-kicks," 152. Cowi)er's glands, 362. Cranial bones, 45. nerves. 490. Cranium. 37, 42. Crest, 14. Cribriform plates, 64. Crista galli process, 54. Crura cerebri, 477. of diaphragm, 203. penist 364. Crural aponeurosis, 202. arch, 202. Crust, 546. Ocusta petrosa, 290. Ccystalrine lens, 637. Cubo-cuaeiform bone, 104. Csboid bone. 95. Cuneiform bones, 95, 96, 97. bone of carpus, 74, bones of hog, 109. Cuticle. 541. Cutigeral groove, 645. Deep fascia, 252. veins of arm, 445. Deltoid ridge, 68. Density of bone, 8. Dental formulffi, 294. Dentata, 27. Dentine, 289. Dentition, 288. ; in Carnivora, 380. in Hog, 377. In Rodentia, 383. In Ruminant, 366. Depressions, articular, is. non-articular, 14. Dermis, 542. Descriptive anatomy, 6. Development of bone. 15. of foetus, 561. of teeth, 295. of ulna, 72, 104. Diaphragm, 208. Diaphysis. 16. Diarthrosis, 127. Diastema, 38, 57, 63. Digit, bones of, 79. Digestive system. 275. in Aves, 384. in Carnivora, 380. in Omnivora, 377. in Bodentia, 383. in Buminant. 365. Diploa of bone, 11. Dissection, general directions for, 565. of articulations and ligamentaL 565. of lymphatic system. 573. of muscles, 666. of nervous system, 674. of organs of digestion, 563. of organs of circulation, 57o. Distal, 20. phalanx, 81. Division of skeleton, 20. of skull, 37. of sphenoid bone, 52. of anatomy, l. Domesticated Aves, 5. Mammals, 4. Dorsal nerves, 505. vertebrsB. 28. Dorso-lumbar fascia, 253. Duct, hepatic, 3i7. of Bartholini, 366. of Nuckius, 380. of Bivinus, 287. of Steno, 286. of Warton, 287. of Wlrsung, 318. thoracic, 451. Ductus ad nasum, 541. arteriosus, 40l, 559. choledochus, 317. cochlearis, 531. communis, 317. lactiferus, 364. lymphaticus dexter 468. pancreatlcus minor, 3l9i. reuniens, 531. Duodenum, 304. Eae, 525. Eiaculatory ducts, 351. Elbov? joint, 136. Embryo, 656. Embryogenlc tissue, 556. Embryology, 2, 556. Eminence of Vater, 317. Eminences, anticular, 14. ilio-pectineal, 86. non-articular, 14. Enamel, 290. Encephalic circulation, 485. Encephalon, 473. ' Endocardium. 396. Endolymph, 531. Endoskeleton, 17. Endosteum, il. Endothelium, 271. Ensiform cartilage. 36. Epidermis, 541. Epididymis, 350. Epiphysis, 16. Epithelium. 270. Eauidae. characteristics of the. 4. Erectile tissue, 354. Ethmoid bone, 54. 588 Ethmoidal sinus, 45. Eustachian tubes, 528. openings for, 51. Exoskeleton. 17. External ear, 625. jugular vein. Rodents, 462. Eye, 532. appendages of, 538. in Aves, 554. Fabella: in Carnivora, 113. Rodentia, 115. Facet, articular, 15. Facial bones, 54- Fallopian tubes, 358. False vertebrae, 23. Falx cerebelli, 470. cerebri, 470. Fascia, 159. arrangement of, 252. crural, 202. deep, 252. deep abdominal, 253. inguinal, 347. of the anterior limb, 254. of external oblique, 202. of the head, 253. of the posterior limb, 255. of the trunk, 253. perineal, 356. ■ plantar, 228. Pat, 123. Feathers, anatomy of. 554. classiflcation of, 554. Felidse, retractor ligament of claw, 267. Female genital organs, 357. in Ruminants, 376. Female pelvis, 88. Femur, 89. Ferrein, tubes of, 343. Fetlock joint, 140. Fibro-cartilage, yellow. 122. varieties of, 121. Fibula, 93. Fifth ventricle, 481. Fissures, 15. of Sylvius, 477. of the cord, 472. Flat bones. 13. Foetus, 556. circulation in, 659. Foot. 544. circulation of, 417. 439. soft structures of, 549. Foramen, i*. aortic (hiatus), 209. cibcum, 474. condyloid, 46. dental, 57. dextrum, 209. Eustachian, 51. external auditory (meatus), 51. incisivum, 58. inferior dental, 63. infra-orbital. 56. internal auditory (meatus), 50. internal orbital, 52. lacerum basis cranii, 40. lacerum orbitale, 53. lachrymal (conduit). 56. magnum, 45. mental, 63. obturator, 87. of Fallopius (aqueduct), 61. of Monro, 481. of the vestibule faqueduct), 61. optic, 62. palatine, 56, 60. parieto-temporal (co^iduit), 42, 60. patheticum. 93. plantar, 82. ForeLmen, preplantar, 82. pterygoid, 30, 52. rotundum, 53. sinistrum, 209. spheno-palatine, 57, 60. stylo-mastoid, 51. styloid, 51. subsphenoidal, 39, 52. supra-orbital, 48. Vidian (canal), 52. 60. Fore-arm, bones of. 70. Fore-limb, bones of, 66. Forms of uterus in mammalia, 384. Fornix, 480. Fossa, 14. cavernous, 53. lachrymal, 59. nasal, 44. navicularis, 353, 362. orbital, 41. sphenoidal, 45. supracondyloid, 89. temporal, 41. Fourth ventricle, 476. Frog, 547. band, 548. sensitive, 550. Frontal bone, 48. sinus, 44. Fundus acetabuli, 87. Funicular ligaments, 124. tendons, 159. Ganglia, Andersch's, 499. Gasserian. 493. genicular, 498, guttural, 516. inferior cervical, 618. jugular, 500. lenticular, 515. Meckel's, 516. of spinal nerves. 503. otic, 516. petrosal, 499. semilunar, 520. superior cervical, 516. sympathetic, 615. Gartner, canals of, 376. General view of the skull, 37. Generative system, 346. Genicular ganglion, 498. Genital system in early foetal life, 368. in Ruminant, 37.^ Genito-urinary organs in Aves, 386. ^. . ^ ., Rodents, 383v Giant's Cells. 12. Gizzard, 384. Glands, 274. Brunner's, 306- buccal, 277. ceruminous. 626. Cowper's, 352. ductless, 274. gastric, 303. lachrymal, 540. liver, 312. lymphatic. 460. mammary, 363. minor salivary, 287. molar, 277. mucous, 272. Nabothian, 361. of Harder, 640. of intestines, 306. of pancreas, 318. of skin, 642. parotid, 285. prostate, 351. salivary, 285. solitary, 306. spleen, 319. submaxillary. 287. INDEX. 589 Glands, sublingual. 287. thyroid and thymus, 335. uropygeal, 555. Glans penis. 354. Glandular epithelium, 271. Glaserian Assure, 51. Glenoid cartilage, 142. cavity, 15. Globe of the eye, 582. Glosso- facial artery in Carnivora, 462. Graafian vesicle, 358. Great cerebral commissure, 479. Grey matter of the cord, 472. Groove, bicipital, 69. palatine, 56. staphyline, 60. Gums, 277. Guttural ganglion, 516. ' pouches, 531. Gyrus fornicatus, 479. "Hmmat, system, 3. Hair, 423, Harderian glands, 540. Haversian canals, 9. Haw. 539. Head, articular, 14. Heart, 388. in Aves, 462. in Carnivora, 461. in lower animals, 463. in Rodents, 462. in Ruminants, 458. muscular fibres of, 395. structure of, 394. Heels, 545. Helicotrema, 530. Henle, tubes of, 343. Hermaphrodite, 363. Hiatus, 14. aortieus, 209. maxillary. 57. of Winslow, 322. optic, 43, 53. orbital, 5-2. Hind limb, bones of, 88. Hip joint, 145. Hippocampus, 481. Hippotomy. 3. Histology, 2. Hock joint, 149. Homology and Analogy, 6. Hoof, 544. . in Ruminantia, 552. Horn tissue, 548. Horns in Ruminantia, 552. Horny laminae, 545. Humerus, 68. Humours of the eye, 536. Hyaline cartilage, varieties of, 121. Hyaloid membrane, 537. Hymen, 362. Hyoid series of bones, 64. articulations of, 135. Ileum, 305. Iliac arteries in Carnivora, 461. Ilium, 84. Incisura sphenoidalis. 48. Incus, 527. Inferior cervical ganglion, 518- maxilla, 62. pyramids. 474. Infundibu]um,478. Ingluvies, 384. Inguinal canal, 203. Injection of arteries, 571. of lymphatics, 573. of veins, 573. Interdental space, 38. 57, $3. Intermediate fasciculi, 475. Internal ear, 529. Internal iliac artery of Omnivora, 461. maxillary artery in Carnivorei, 462. Interpeduncular space, 478. Intervertebral discs, 129. Intestines, 304. glands of, 306, in Aves, 384. in Carnivora, 381. in Omnivora, 378. in Ruminants, 371. large, 3C7. small, 304. Introducti6n, 1. . Invertebrata and vertebrata compared, 3, Iris, 535. Irregular bones, 13. Ischium, 86. Island of Reil, 477. Isthmus faucium, 278. Iter ad infundibulum, 483. e tertio ad quartum ventriculum, 483. Jejunum, 305. Joint oil, 125. Jugular confluent, 446. ganglion, 500, gutter, 446. vein, 446. Keratogenous membrane, 55() Keratophyllous tissue, 545. Kidneys, 340. Labyrinth, 529. membranous, 531. Lachrymal apparatus, 540. bone. 59. conduit, 56. duct, 541. . fossa, 59. gland, 540. Lactiferous duct, 364. sinuses, 364. Lacunae of bone, 9, Lamina spiralis, 530. Lamprey, 4. Laneelet, 4. Larynx, 327. cartilages of, 327. intrinsic muscles of, 331. ligaments of, 329. extrinsic muscles of, 331. ventricles of, 330. Lateral cartilages. 549. sinuses, 489. ventricles, 480. cornua of, 480. Lamina cinerea, 479. cribrosa, 533. Left auricle, 392. ventricle, 393. Lenticular ganglion, 515. Levator palatl muscle, 279. Ligaments, 124. arcuate, 209. broad, I4i. calcaneo-cuboid, 150. capsular, 124. cervical, {ligamentum tiucficeX 130. check, 227, 228. common of carpus, 139. common of tarsus, 149. common vertebral, 129. crico-trachealis, 329. funicular, 124. inferior sesamoidean, 141. laryngeal, 329. obturator, 145. of bladder, 345. of liver. 314. 590 INDEX. liigamects of uterus, 360. of tympanum, 528. of vulva, 3«3. Poupart's, 202. pubio-femoral, 146. retractor of claw in cats, 267. round, 146. sacro-sciatic, 144. special carpal, 137. special tarsal, 150. special vertebral, 130. superior sesamoidean, 141. suspensory, I4i. transverse odontoid, 153. V, X, and Y. 141". Limb, bones of pectoral, 66, of pelvic, 88. Unea alba, 201. semilunaris, 200. Lips, 276. Liquor amnii, 557. Contunnii, 530. Morgagni, 537. Scarpae, 531. Liver, 312. in Omnivora, 379. ligaments of, 314. structure of, 314. Locomotion, organs of, 6, Locus niger, 478. perforans, anticus and posticus, 478. Long bones, 12. Longitudinal sinuses, 489. Low forms of vertebrata, 4. Lumbar nerves, 505. vertebrae, 30. Lunar bone, 74. Lungs, 337. Lymph, 451. corpuscles, 451. Lymphatic system, 449. vessels, 449. Lymphatics, brachial, 457, deep inguinal, 463. bronchial glands, 455. glands, 450. guttural, 457. iliac, 453. in bone tissue, 12. in ruminants, 460- of abdominal viscera, 454. of anterior region, 456. of caecum, 454. of diaphragm, 456, of large colon, 454. of liver, 455. of posterior region, 452. of rectum and floating colon, 454. of spleen, 455. of stomach, 455. of thoracic viscera, 455. of thoracic walls, 456. popliteal, 453. precrural, 453. prepectoral, 456. prescapular, 457. sublumbar, 452. submaxillary, 457. superficial inguinal. 453. valves of, 450. vein, 458. Lyra, 481. Malab Bone, 5R. Male gejiital organs. 346. in Ruminant, 375. Malleolar bone, 104. Malleus, 527. Malphigian bodies, 341. corpuscles, 321. Mammalia, 4. Mammals, domesticated, 4, Mammary glands, 263. Mammillary eminence, 478. processes, 115. Mandible, 62. Manubrium, 103. Marrow, 12. Mastoid ridge, 46. Maxillary hiatus, 57. Maxilla inferior, 62, pre-, 57. superior, 56. Maxillary nerve, inferior, 495. superior, 494, rami, 38. sinus, 44. space, 38, 62. Meatus, 14. external auditory, 51. internal auditory- 50. nasal, 62. urinarius, 354. Meckel's ganglion, 5i6. Median phalanx, 81. Mediastinum, 337. testis, 349. Medulla oblongata, 473. Medullary cone, 471. Meibomian glands, 539. Membranes, basement, 272. basilar, 531. fusca. 534. mucous, 272. nictitans, 539. of Reifesner, 531. osteogenic, 17. pupiharis, 535. serous, 273. synovial, 124. tympanic. 526. Meninges of the brain. 469. cord, 468. Meniscus, 134. 147. Mesenteries, 321. Metacarpal articulation, 140. bone, large, 77. bones, small, 78. Metacarpus, 77. Metapophyses, 115. Metatarsal bones, 97. Metatarsus, 97. Middle ear. 526. Minute anatomy, 2. structure of bone, 9. Monro, foramen of, 481. Morbid anatomy, 2. Morphology, 2. Motion in joints, 128. Motores oculorum, 492. Mouth, 276. bars of, 63. Mucous membranes, 272. Muscles, abdominal region, 200. abdncens, 177. abductor brevis pollicis, 267 abductor minimi digiti. 267, accelerator urinae, 355. acromio-humeralis, 266. adductor brevis, 238. adductor Indicis, 267. adductor longus, 239. adductor magnus, 239. adductor minimi digiti, 267. anconeus, 221. antea-spinatus, 213. anterior femoral region, 241. anterior maxillary group, 16\ anterior tibial group. 245. antibrachial extensor group. 2*2. antibrachial flexor group, 226. aryteno-pharyngeus, 298. INDEX. 591 Muscles, arytenoideus, 333. attollens anticus, 175. attollens maximus, 174. attollens posticus, 176. auricular group (extrinsic), 174. auricular group (intrinsic), 177. biceps rotator tibialis, 244. brachial group (anterior), 217. brachial group (posterior), 219. buccinator, 163. caput magnum, 220. caput medium, 220. caput parvum, 221. cervical region, 178. coccygeal region, 210. complexus major, 186. complexus minor, 187. compressor coccygis, 211. constrictores vulvae, 363. coraco-humeralis. 218- costal region, 190. cremaster, 355. crico-arytenoideus lateralis. 332. crico-arytenoideus posticus, 332. crico-pharyngeus, 298. crico-thyroideus, 332. crural group, 242. crurerus, 243. curvatoi- coccygis, 211. depressor coccygis, 210. depressor labii inferioris, 167. depressor labii superioris, 166. diaphragm. 208. digastricus, 170. dilatator naris inferioris, 166. dilatator naris lateralis, 165. dilatator naris superioris, 166. dilatator naris trausvorsalis, 166. dorso-lumbar region, 198. erector clitoridis,a63. erector coccygis, 210. erector penis. 356. extensor communis digitorum, 262. extensor metacarpi magnus, 222. extensor metacarpi obliquus, 223. extensor pedis, 223, 247. extensor pedis brevis, 252. extensor poUicis et indicis. 266. extensor proprius externus, 262. extensor proprius internus, 262. extensor suffraginis. 224. femoral abductor group, 239. femoral adductor group, 236. flexor brachii, 21?. flexor brevis pollicis. 267. flexor metacarpi externus, 225. flexor metacarpi internus, 226. flexor metacarpi medius, 226. flexor metatarsi, 245. flexor minimi digiti, 267. flexor pedis accessorius, 251, flexor pedis perforans, 228, 250. flexor pedis perforatus, 227, 249. frontalis, 261. gastrocnemius, 248. gemelli (gemini), 235. genio-hyo-glossus, 283. genio-hyoideus, 171. gluteal region, 231. gluteus externus, 232. gluteus internus, 233. gluteus maximus. 232. gracilis, 237. humeralis obliquus, 218. hyo-epiglottideus, 331. hyo-glossus brevis, 282. hyo-glossus longus. 282. hyo-glossus parvus, 282. byo-pharyngeus, 298. hyo-thyroideus, 331. Muscles, hyoidean group, 170. hyoideus magnus. 171. hyoideus parvus. 172. hyoideus transversus. 172. iliacus, 207. in birds, 269. inferior cervical group, 178. inferior oblique of eye, 538. intercostales. 194. interossei (hog), 264. interossei metacarpei, 230. intertransversales lumborum, 200. intertransversalis colli. 189. ischio-femoralis. 244, keratopharyngeus, 297. lachrymalis, 173. laryngeal, 331. lateral cervical group, 183. lateralis sterni, 197. latissimua dorsi, 191. levator alas, 269. levator ani, 312. levator humeri, 183. levator labii inferioris, 167. levator labii superioris alaeque nasi, 164. levator palati, 279. levator palpebrae superioris ex» ternus, 173. levator palpebrae superioris in- ternus. 174. levatores costarum, 193, lingual, 281. lingualis, 283. longissimus dorsi, 198. longus colli, 182. lumbricales, 231. masseter, 168. mastoido-auricularis. 177. metacarpal region, 230. metatarsal region, 252. mylo-hyoideus, 170. nasalis longus, 164. obliquus abdominis externus. 201. obliquus abdominis internus, 209, obliquus capitis anticus, 188. obliquus capitis posticus, 188. obturator externus. 234. obturator internus, 235. of dog's paw, 266. of eye, 537. of female genital system. 363, of head, 162. of larynx. 331. of limbs. 211. of male genital organs, 355. of pectoral limb, 212. of pelvic limb, 231. of pharynx. 297. of Phillips, 224. of soft palate. 278. of Thiernesse, 224. of tongue, 281. of trunk, 178. of tympanum. 528. opponens. 267. orbicularis oris, 164. orbicularis palpebrarum, 173. palatoglossus, 280, 283. palato-staphylinus, 280. palmares, 267. palmaris brevis, 267. palpebral group, 173. panniculus carnosus, 161. pectiiieous. 237. pectoral region and group, 194. pertoralis anticus, 196. peetoralis magnus, 196. pectoralis parvus, 197. peetoralis transversus. 195. 692 Muscles, peroneus, 2il. peroneus longus lateralis, 263. pharyngeal, 297. pharjngo-glossus, 283. pharyngo-staphylinu.s, 279, 297. plantaris, 249. popliteous. 251. postea-spinatus, 2U. postea-spinatus minor, 2U. posterior femoral region. 244. posterior maxillary group, 167. posterior tibial group. 248. pronator auadratus, 266. pronator teres, 266. psoas magnus. 205. psoas parvus, 206. pterygo-pharyngeus, 297. pterygoideus externus, 169. pterygoideus intern us, 169. pyriformis, 235. auadratus lumborum, 207. Quadriceps cruralis, 242. radialis aecessorius, 230. recti oculi, 537. rectus abdominis, 204. rectus capitis anticus major, 180. rectus capitis anticus minor, 181. rectus capitis lateralis, 181. rectus capitis posticus major, 187. rectus capitis posticus minor, 187. rectus femorls, 242. rectus parvus, 234. retractor ani, 312. retractor oculi, 537. retractor penis, 356. retrahens externus, 176. retrahens internus, 177. retrahens medius, 176. rhomboideus brevis, 190. rhomboideus longus, 184. sarforius, 236. scalenus, 181. scapular group (pxternal), 212. scapular group (internal), 215, scapulo-humeralis posticus (grele). 216.. scapulo-ulnaris, 219. scuto-auricularis externus, 178. scuto-auricularis internus, 178. semispinalis dorsi et lumborum, 199. serratus magnus, 185, 192. sphincter ani, 311. spinalis colli, 189. spinalis dorsi, 199. splenius, 185. sternal group, 197. sterno-maxillaris, 179. sterno-suboccipitalis, 261. sterno-thyro-hyoideus. 179. stylo-hyoideus, 172. stylo-maxillaris, 168. subcutaneous region, 161. subscapularis, 215. subscapulo-hyoideus, 180. sublumbar region, 205. superfleialis costarum, 192. superior obliQue of eye, 538. supinator brevis, 266. supinator longus, 266. temporalis, 168. tensor fasciae latae, 241. tensor palati, 278. teres externus, 212. teres internus (major), 215. thyro-arytenoideus, 333. thyro-pharyngeus, 298. tibial region, 245. tibialis anticus, 263. tibialis posticus, 268. trachelo-altoideus, 261. ' trachelo-mastoideus, 186. Muscles, transversalis abdominis, 205. transversalis costarum, 193, trapezius cervicalis, 184. trapezius dorsalis, 190. triangularis sterni, 198. triceps abductor femoris, 240. triceps adductor femoris, 238. triceps cruralis, 242. triceps extensor brachii. 219. ulnaris accessorius. 229. vastus externus, 243. vastus internus, 243. Wilson's, 356. zygomaticus, 163. ' Muscular attachments, table of, 256. classification, 160. nomenclature, 160. tissue, 155. Myelon, 47i. Myology, 155. comparative, 260. NaBES, ANTEBIOR. 42. posterior, 39. Nasal bone, 54. chambers. 335. duct, 541. fOSSiB, 44. meati , 62. Natatores, 6. Nates, 484. Navicular bone, 83. Neck of a bone, 14. Nerve cells, 466. Nerves, 467. abducens, 497. anterior auricular, 498. anterior palatine, 494. anterior scapular, 508. anterior tibial, 514. auditory, 499. auricular plexus, 503. axillary, 508 brachial plexis, 508. bronchial plexus, 501. buccal, 496. cardiac, 518. carotid ple.xus, 518. Cauda eauina, 506. cavernous plexus, 517. cephalic portion of sympathetic, 515. cervical, 503. cervical portion of sympathetic, 516. chorda tympani, 498. circulatory depressor, in Babbit. 524. classification of, 468, 490. cochlear, 499. coccygeal, 50". cranial, 490. crural, 512. cubital, 5Q9. deep cervical plexus, 504, dental, 494, 496. digital, 511,514. dorsal. 505. external popliteal, 514. external saphenic, 514. facial, 497. facial branches of fifth, 494. gastric plexus, 520. glosso- pharyngeal, 499. gluteal aute-ior, 512. gluteal posterior, 512. great sciatic, 513. great splanchnic, 520. gustatory, 496. guttural plexus, 516. tiEemorrhoidal. 507. hepatic plexus, 520. INDEX. 593 Servos, hypogastric plexus. 507, 521. hypoglossal, 502. illiaco-muscular. 512. ilio muscular, 512. in Aves, 524. in Carnivora, 523. in the Hog, 523. in Ruminants, 522. inferior dental, 496. inferior maxillary, 495. inguinal, 506. intercostal, 505. intermediate cord of cervical ganglia, 518- internal metacarpal, 5lo. internal pudic, 507. internal saphenic. 512. ischio-muscular, 512. Jacobson's, 500. lachrymal. 494. lesser splanchnic, 521. lingual, 496. lumbar, 505. lumbar portion of sympathetic, 521. lumbo-aortic plexus, 520. lumbo-sacral plexus, 5ii. masseter, 495. median, 509. mental, 496. mesenteric plexus, 520. metacarpal, 5ii. metatarsal. 514. middle auricular, 499. motores oculorum, 492. musculo-cutaneous (fore-limb), 510. musculo-cutaneous (hind-limb), 514. mylo-hyoidean, 496. nasal, 494. obturator, 512. olfactory, 491. ophthalmic, 493. optic, 491. orbital, 494. origin and termination of, 467. parvagum,500. pathetic, 492. pharyngeal plexus, 518. phrenic, 507. pneumogastric. 500. portio dura, 497. portio mollis, 499. posterior auricular, 499. posterior crural, 514. posterior mesenteric plexus, 521. pterygoid, 496. radial, 508. recurrent laryngeal, 501. renal plexus, 520. sacral, 506. saoral portion of sympathetic, .. 521. solar plexus, 520. spermatic plexus, 521, spheno-palatine, 494. spinal, 502. spinal ascessory, 502. sp'enic plexus, 520. staphyline, 494. subscapular, 508. subzygomat'c, 496. superficial cervical plexus, 504. superficial petrosal, 498. superior dental, 494. superior laryngeal, .500. superior maxillary, 494. supraorbital. 493. suprarenal plexus, 520. sympathetic system, 615. temporo-facial, 499. Nerves, thoracic, 508. thoracic portion of sympthetio, 519. tibial, 513. tracheal plexus, 519, trifacial, 492. ulnar. 509. vestibular, 499. Vidian, 498. Wrisberg's, 498. Nervous tissue, 466. Neural canal, 3. Neuroglia, 473. Neurology, 465. comparative, 522. Nomenclature, muscular, 160. Non-articular depressions, 14. eminences. 14. Non-stnated muscular tissue, 157 Nostrils, 323. Notch, 14. carotid, 53. cotyloid, 87. inferior maxillary, 53. Notochord, 4, 557. Obtubatob foramen. 87. ligaments, 145. Occipital bone, 45. bone, segments of, 46. sinuses, 489. Ocular sheath, 541. Odontoid ligament, transverse. 153, process, 27. (Esophagus, 298. Olecranon process, 72, Olfactory bulbs, 479. Olfactory lobes in carnivora, 523, nerves, 491. Olivary bodies, 474. Omenta, 322. Omnivora, characteristics of, 3. skin in, 552. Opthalmic nerve, 493. Optic hiatus, 43, 53. lobes, 484. nerves, 491. thalami, 482, tracts, 478. Orbital fossa, 41. hiatus, 52. Organs of locomotion, 6. Oscalcis, 94. coronas, 81. hyoides, 64. innominatum, 84. magnum, 76. orbiculare, 527. pedis, 81. suffraginus, 80. triquetrum. 48. uteri, 361. Osseous tissue, 9. Ossiflc centres, 15. tentorium, 42, 47. Ossification, 15, Osteoblasts, 11. Osteology, 7. comparative, 98. Osteogenic membrane, 17. Ostium internum, 361. uterinum, 3tii. Otic ganglion, 616. Oto-conise, 531. Ovary, 357. Oviduct, 358, 386. Ovum, 358. after fecundation, o8fi. Pacinian bodies, 467. Palate, hard, 277. soft, 277. 594 INDEX. Palate, blood supply of, 280. muscles of, 278. Palatine arch, 38, 60. bone, 59. groove, 66. Pancreas, 3i8. Pancreas and liver in Avea, 384. Panniculus adiposus, 542. Papillae of the tongue, 284. Parietal bone, 47. branches of posterior aorta, 403. Parotid gland, 285. Par-ovarium, 359. Pastern bone, large, 80. bone, small, 81. joint, 142. Patella, 91. Pathetic nerves, 492. Pecten, 554. Pectoral arch, 66. arch in birds, 117. limb, 66. articulations of, 136. fascia of, 254. Peduncles of the cerebellum, 476. cerebrum, 477. Pelvic apertures 87, arch, 83. cavity, 83. limb. 88. articulations of, 143. fasciae of, 255. symphpsis, 146. Pelvis, 83. Penis, 353. arteries and nerves of, 366. Pericardium, 397. Perichondrium, 121. Pericranium, 12. Perilymph, 530. Perineal fascia. 356. Perinaeum, 356, 362. Periople, 545. Perioplic ring, 551. Periosteum, 11. Perissodactyla, 4. Peritoneum, 321. Petrosal bone, 50. ganglion, 499. sinuses, 489. Phalanx, distal, 81. median, 81. proximal, 80. Pharyngeal muscles, 297. Pharynx, 596.. Phrenic centre, 208. Physiology distinguished from Anatomy, 2. , Pia mater. 469, 471. Pineal gland. 484. Pisiform bone. 77. Pituitary gland, 478. Placenta, 557. Plantar aponeurosis, 228. strengthening sheath, 229. Pleurae, 337. Plexuses. See Nebves. Pneumatic bones, 119. Pneumogastric nerve, 500. Podophyllous tissue. 550. Pons Tarini. 478. Varolii, 475. Portio dura, 497. Portio mollis. 499. Porus opticus, 533. Posterior aorta. 402. bifurcation of, 409. parietal branches of, 403. visceral branches of, 404. nares, 39. vena cava, 436. Poupart's ligament, 202. Practical anatomy, 2. Preening in birds, 656. Fremaxilla, 57. Premaxillary symphysis, 5H. Prepubian tendon, 201. Prepuce, 355. Process, 14. basilar. 46. • crista galli, 54. olecranon, 72. olivary, 53. pyramidal, 82. Pronation, 154. Prostate gland, 35i. vesicle, 351. Proventriculus, 384. Proximal, 20. phalanx, 80. Pterygoid bone, 60. Pterygoidean fasiculus, 431. Pubio-femoral ligament, 146. Pubis, 86. Pulmonary artery, 400- Puncta lachrymalia, 540. vasculosa, 479. Pupil, 535. Pyramidal process, 82. QUADBATO-JUGAX, BONE, 117. Ouadrate bone, 117. Quarters, 545. Rachis, 554. Rachitis, 8. Radio- ulnar arch, 70 Radius, 70. Rami of the Jaw, 38. Receptaculum chyli. 451, In Carnivora, 462. Rectum, 3io. Removal of the hoof, 567. Renal-portal system, 463. Respiratory organs, 323. in Aves, 385. in Carnivora, 382. in Omnivora,379. in Ruminants, 374, Respiratory system, 323. Restiform bodies, 474. Rete mirabile, 460. mucosum, 641. Reticular cartilage, 122. Retina, 535. Ribs, 33 special, 36, Ridge, 14. mastoid, 46. semilunar, 82. Rigl^t auricle, 389. ventricle, 391. Rings, abdominal, 203. Rodentia, albinos in, 5.S3. appendicular skeleton, 116, characteristics of. 5. axial skeleton, 114 " Roosting." mechanism of, 2r,9. Ruminantia, appendicular skeleton of,106. bones of skull, 9k characteristics of, 4. horns in, 552. vertebrae of, 102. visceral skeleton of. 105. Sacculus communis, 531. proprius, 531. Paccus endoly 'nphaticus, 531. Sacral nerves, 506. vertebrae, 31. Pacro-iliac joint, 143. Sii'To-lumbar arliculation, 132. Sacro-sciatic ligament, 144. INDEX. 595 Sacrnm, 31. Saliva, 288. Salivary glands. 285. Scala intermedia, 531. tympani, 530. vestibuli, 630. Scaphoid, 73. Scapula, 66. Scapus, 554. Schneiderian membrane, 526. Sclerotic coat, 532. Scrotum, 347. Scutiform cartilage, 526. Sebaceous glands, 542. Sella turcica, 53, Semicircular canals. 530. Semilunar cartilages, 347. ganglion, 520. ridge, 82. Seminal fluid, 356. Sensation, organs of, 525. Sensitive frog, 55(i. laminae, 551. sole, 551. Separate bones of the skull, 45. Beptum lucidum, 480. pectiniforme, 354. Serous membranes, 273. Sesamoid bones, large, 80. small, 83. Sesamoidean ligaments, 141, Sharpey, fibres of, 10. Sheath, 355. Shoulder joint, 136. Sinus pocularis, 351. Sinuses, cavernous, 489. ethmoidal, 45. frontal, 44. lactiferous, 364. lateral, 489. longitudinal, 489. maxillary, 44. occipital, 489. of tne dura mater, 488. of the skull, 44. petrosal, 489. sphenoidal, 45. transverse, 489. Skeleton, 17. appendicular. 65. axial, 21. division of, 20. in Birds, 115. in Carnivora, log- in Hog, 105. in Rodentia, 114. in Ruminants, 98. Skin, 541. in Carnivora, 553. in Omnivora, 552. Skull, articulations of, 134. cavities in, 42. division of, 37. general view, 37. of Dog, 109. of Hog, 105. of Ruminant, 98. separate bones of, 45. sinuses of, 44. sutures of, 134. Snout, 379, ^ole. 546. Solidungula, 4. Space, atlo-axoid, 28. interdental, 38, 57, 63. maxillary, 62. Special anatomy, l. ligaments of carpus, 137. ligaments of tarsus, 150. . ribs, 35. vertebral articulations, 131. vertebral ligaments. 130. Speculum Helmontii, 208. Spermatic cord, 347. Spermatozoa, 356. Sphenoid bone, 52. Sphenoidal sinus, 45. Spheroidal epithelium, 271. Spinal accessory nerve, 502. Spinal cord, 471. meninges of, 468. Spine, 14. Splanchnology, 270. comparative, 365. Spleen, 319. Splint bone, 78. Squamosal bone, 49. Squamous epithelium, 270. Stapes, 527. Sternal articulations, 134. Sternebrae, 35. Sternum, 35. Stifle bone, 91. joint, 146. Stomach, 30i. in Carnivora, 381. in Omnivora, 378. in Rodents, 383, in Ruminants, 366. Strangeways on a supernumerary obliaw'' muscle of the eyeball, 575. Strengthening plantar sheath, 229. Striated muscular tissue, 156. Structure of bone, 7. minute, 9. Sudoriferous glands, 542. Superflcial fascia, 159. Superior maxilla, 56. pyramids, 475. Supination, 154. Supracondyloid fossa, 89. Suprarenal capsules, 343. Surfaces of bones, 14. Surgical anatomy, 2. Suspensory ligament, 141, Sutures, 126. of the skull, 134. Symmetry, bilateral, 19. Sympathetic system of nerves, 516. Symphysis, pelvic, 145. premaxillary, 58. inferior maxillary, 63. Synarthrosis, 126. Syudesmology, 120. Synovia, 125. Synovial bursas. 125. membranes, 124. Syrinx, 285. System, hsemal, 3. Table of muscular attachments, 256. Taenia semicircuiaris, 482. Tapetum lucidum, 534. in carnivora 658 Tarsal cartilages, 539. Tarsus, 93. Teeth 288. 'arrangement, and kinda«»f, 290. canine. 293. in Carnivora. 380. in Rodents, 383. incisor, 291. molar, 293. Temporal bone, 49. fossa, 41. Temporary cartilage, 15. Temporo-maxillary joint, 134. Tendons, 158. Tendo-Achillis, 248. Tendon, prepubian, 201. Tentorium cerebelli, 470. ossiflc, 42. 47. Testicle, 596 INDiiX. Testicle in Carnivora, 383. Tensor palati muscle, 278. Third ventricle, 483. Thorax. 33, 336. Thoracic articulations, 132. duct, 451. Thoracic duct in Omnivora, 461. Thyroid and Thymus glands, 335. Tibia, 91. Tibial arch, 93. Tibio-fibular articulation, 148. Tissue, adipose, 123. cancellated, 10. compact, 9. connective, 122. horn, 548, muscular. 155. osseous, 9. white fibrous, 122. yellow elastic, 123. Tongue, 280. muscles of, 281. papillae of, 284. Torcular Herophili, 489. Touch-hairs, 553. Trachea, 334. Transcendental anatomy. 1. Transverse sinus 489. Trapezium, 75. Trapezoid, 75 . Trifacial nerves, 492. Trochanter, 14. Trochlea, 19. True vertebrae— general view, 21. Tuber cinereum, 478. Tubercle, 14. Tuberosity, 14. Tubuli uriniferi, 341, seminiferi, 349. Tunica abdominalis, 200. albuginea, 349, 358, 553. Ruyschiana. 534. vaginalis, 348. vasculosa, 349. Tunics of the eyeball, 532. Turbinals. 61. , Turner, Professor, on a muscle connected with orbital periosteum, 577. Tusks, 5. / Tympanic membrane, 526, Tympanum, 526. Types in anatomy. 1. Ulna, 71. development of, 72. 103. Umbilical cord, 558. Umbilicus, 201. Unciform bone, 76. Ungulata, 4. Urachus, 558. Ureters, 343. Urethra, 352. Urinary system. 340. Urino-genital system in Aves, 386. in Carnivora, 382. in Omnivora, 379. in Rodentia, 383. in Ruminants, 374, Uropygeal gland, 555. Utero-gestation, 656. Uterus, 359. forms of, 384. Vagina, 361. Valve of Vieussens, 475. Vas deferens, 350. Vater, eminence of, 317. Veins, structure of, 433. alveolar, 447. angular, 447. anterior auricular, 446. Veins, anterior cava, 442. anterior mesenteric, 437. anterior radial 445. anterior tibial, 441. azygos, 444. basilic. 445. brachial, 444, 445. bronchial. 435. buccal, 449. cardiac, 435. cephalic, 445, 449. 1 common iliac, 438. coronary, 435, 448. coronary plexus, 440. cubital, 44S. deep, of arm, 445. deep, of brain, 488. deep, of posterior limb, 441. deep, or interosseous, of anterior extremity, 444. diaphragmatic. 437. digital, 440, 444. dorsal, 443. dorsans nasi, 447, duodenum, 437. emergent veins of the cranium, 489. encephalic sinuses, 488. external iliac, 439, 442. external saphenic, 442. external subcutaneous of arm, 446. femoral, 442. gastric, 437. gastro-epiploic, 437. gastro-splenic, 437. glosso-facial, 447. hepatic, 437. humeral, 445. in Aves, 463. in Omnivora, 461. In Ruminants, 460. inferior communicating, 449. internal iliac, 442. internal maxillary, 447. internal saphenic, 441. internal subcutaneous of arm, 446, internal thoracic, 443. interosseous of foot, 440. jugular, 446. jugular, branches of, 447. jugular confluent, 446. laminal plexus, 439. lateral coronary plexus, 440. lateral nasal, 447. lesser azygos, 443. lingual, 447, lumbar. 438. maxillo-muscular, 447. metacarpal, 444. metatarsal, 440. middle coronary. 440. occipital, 447. of the brain. 488. of the foot, 439. of the Frog, 440. pancreatic, 437. parietal-temporal (confluent), 489t pedal plexuses of ante"rior limb, 444. phrenic, 437. popliteal, 442. portal, 437. posterior auricular, 447. posterior mesenteric, 437. posterior radial, 444. posterior tibial, 441. posterior vena cava, 436. pulmonary, 435. pyloric, 437. renal, 437. sa^hena major, 441. saphena minor. 442. satellite, 434. mDEX. 597 Veins, sesamoidean arch, 440. solar plexus, 439. spermatic, 437. spermatic plexus, 438. spinal, 490. spur, 445. subcutaneous thoracic, 445. sublingual, 449. subsphenoidal (confluent), 489. subzygomatic, 446. superior cerebral, 446. superior cervical, 443. superior and inferior coronary, 448, superficial of arm, 445. superficial of arm, 445. superficial of brain, 488. superficial of posterior limb, 441. superficial temporal, 446. systemic, 435. thyroid, 449.- ulnar, 445. umbilical, 559. utero-ovarian, 438. ^ valves of, 434. vena varicosa, 447. vertebral, 443. venae vorticosas 534. vetlum interpositum, 482. Ventricles of brain, 476. of heart, 389. of larynx, 330. Vermiform process, 475. Vertebrae, cervical, general features, 23. cervical, special, 26. cervical, the two last, 28, coccygeal, 32. dorsal, 28. false, general view. 23. in the Dog, ill. in the Hog 107. Vertebrae, in Ruminants, 102. lumbar, 30. sacral, 31, true, general view, 21. Vertebral column, 21. Vertebrata, 3. low forms of, 4. Verumontanum, 353. Vesiculae seminales, 350. Vessels of bone tissue, 12. Vestibule. 5-29. Veterinary anatomy, 2. Vexillum, 554. Visceral branches of posterior aorta, skeleton in Carnivora, 113. in fiuminantia, 105. Vidian fissure, 52. Vitreous humour, 535. Vomer. 61. Vulva, 361, Wall of the hoof, 545. Wattles, 655. Web-ffe>t, 555. White fibrous tissue, 122. Wind galls, 142. Withers, 30. Wolffian bodies, 557. Wormian bone, 48. xlvbocd cabtilage, 3s. Yellow elastic tissue, 128. Zonula of Zinn, 536. Zoology, 1. Zootomy, l. Zygomatic arch, 40. 49. process, 68. CATALOGUE OF William R. Jenkins Co.'s Works Concerning HORSES, CATTLE, SHEEP, SWINE, Etc. 1908 (*) Designates New Books. (f) Designates Recent Publications. ANDERSON. "Vice in the Horse" and other papers on Horses and Riding. By E. L. Anderson. Size, 6x9, cioth, illustrated .1 75 ARM STEAD. " Tlie Artistic Anatomy of tlie Horse." A brief description of the various Anatomical Struc- tures which may be distinguished during Life through the Skin. By Hugh W. Armstead, M.D., F.R.C.S. With illustrations from drawings by the author. Cloth oblong, 10 x 12^ 3 75 BACH, "How to Judge a Horse." A concise treatise as to its Qualities and Soundness ; Including Bits and Bitting, Saddles and Saddling, Stable Drainage, Driv- ing One Horse, a Pair, Four-in-hand, or Tandem, etc. By Capt. F.W. Bach. Size, 5x7^, clo., fully illus.l 00 BANHAM. "Tables of Veterinary Posology and Tliera. peutics," with weights, measures, etc. By Geo. A- Banham, F. R. G. V. S. New edition. Cloth, size 4x5 1-2, 192 pages 1 00 BAUCHER. "Metliod of Horsemanship." Including the Breaking and Training of Horses. By F. Baucher 1 00 BELL. (*)"The Veterinarian's Call Book (Perpetual)." By Roscoe R. Bell, D.V.S., editor of the American Veterinary Review. Completely revised 1907. A visiting list, that can be commenced at any time and used until full, containing much useful informa- tion for the student and the busy practitioner. Among contents are items concerning: Prescription writing; Veterinary Drugs; Poisons; Solubility of Drugs; Composition of Milk, Bile, Blood, Gastric Juice, Urine, Saliva ; Respiration ; Dentition ; Temp- erature, etc., etc. Bound in flexible leather, with flap and pocket. ,,...,,,,,, .,,.,,..,.... 1 25 BITTING. *• Cadiot's Exf rcisf s in Equine Surgery." See ''Cadioi." BRADLJEY. *' Outlines of Yeterinary Anatomy." By O.Charnock Biadlej-, Member of the Royal Col- lege of Veterinary Surgeons ; Professor of Anatomy in the New Veterinary College, Edinburgh. The author presents the most important facts of veterinary anatomy in as condensed a form as possible, consistent with lucidity. l2mo. Complete in three parts. Pakt I. : The Limbs (cloth) 1 25 Part II. : The Trunk (paper) 1 25 Pakt III. : The Head and Neck (paper) 1 25 The Set complete 3 25 CADIOT. " Exercises in Equine Sur^rery." By P. J. Cadiot. Translated by Prof. A. W. Bitting, D.V.M. Edited by Prof. A. Liautard, M.D.V.M. Size, 6 x OX- cloth, illustrated 2 50 — "Roaring' in Horses." Its Pathology and Treatment, This work represents the latest development in oper- ative methods for the alleviation of roaring. Each step is most clearly defined by excellent full-page illusti'ations. By P. J. Cadiot, Professor at the Veterinary School, Alfort. Translated by Thos. J. Watt Dollar, M.E.C.V.S., etc. Cloth, size 5 1-4x71-8, 77 pages, illustrated 75 — "Studies in Clinical Veterinary Medicine and Surgery." By P. J. Cadiot. Translated, edited, and supplemented with 49 new articles and 3t illustrations by Jno. A. W. Dollar, M.R.C.V.S. Cloth, size 7 x 9 3-4, 619 pages, 94 black and white illustrations 5 25 —(*)" A Treatise on Surgical Therapeutics of the Domestic Animals." By F. J. Cadiot and J. Almy. Translated by Prof. A. Liautard, M.D.,V.M. I. General Surgery. — Means of restraint of animals, general anaesthesia, local anocthesia, surgical anti- sepsis and asepsis, hematosis, cauterization, firing, II. Diseases Common to all Tissues.— Inflammation, abscess, gangrene, ulcers, fistula, foreign bodies, traumatic le.sions, complications of traumatic les- ions, granulations, cicatrices, mycosis, virulent diseases, tumors. III. Diseases Special to all Tissues and Affections of the Extremities. — Diseases of skin and cellular tis- sue, of serous bursae, of muscles, of tendons, of tendinous synovial sacs, of aponeurosis, of arteries, of veins, of lymphatics, of nerves, of bones, of articulations. Cloth, size 6x9, 580 pages, 118 illustrations 4 50 CHAPMAN. "Manual of the Pathological Treatment of Lameuess in the Horse," treated solely by mechanical means. By George T. Chapman. Cloth, size 6x9, 124 pages with portrait , 2 OQ CLARKE. "Chart of the Feet and Teeth of Fossil Horses." By W. H. Clarke. Card, size 9 1-2 x 12. . 25 —*< Horses' Teeth." Fourth edition, re-revised, with second appendix. Cloth, size 5 1-4 x 7 1-2, 322 pp., illus.. 2 60 CLEAVJELAND, "Pronouncing Medical Lexicon." Pocket edition. By C H. Cleveland, M.D. Cloth, size 3 1-4x4 1-2, 302 pages 75 CLEMENT. *' Veterinary Post Mortem Examina- tions." By A. W. Clement, V.S. The absence in the English language of any guide in making autopsies upon the lower animals, Induced Dr. Clement to write this book, trusting that it would prove of prac- tical value to the profession. Cloth, size 5x7 1-2, 64 pages, illustrated 75 COURTENA F. (f) " Manual of the Practice of Veterinary Medicine." By Edward Courtenay, V. S. Revised by Frederick T. G. Hobday, F.R.C.V.8. Second edition. Cloth, size 5 1-4x7 1-2, 573 pages 2 75 COX. " Horses : In Accident and Disease." The sketches introduced embrace various attitudes which have been observed, such as in choking ; the disorders and accidents occurring to the stomach and intestines ; affection of the brain ; and some special forms of lame- Hess, etc. By J. Roalfe Cox, F.R.C.V.S. Cloth, size 6 X 9, 28 full page illustrations 1 60 DALRY3IPLE. (*)"Veterinary Obstetrics." A compen- dium for the use of advanced students and Practi- tioners. By W. H. Dalrymple, M. R. C. V. S., principal of the Department of Veterinary Science in the Louisiana State University and A. & M. College; Veterinarian to the Louisiana State Bureau of Agriculture, and Agricultural Experiment Stations. Second edition revised. Cloth, si-'.e 6x9 1-4,162 pages, 51 illustrations 2 50 DALZIEL. " Breaking and Training Dogs." Part I, by Pathfinder. Part II, by Hugh Dalziel. Cloth, illustrated 2 50 — "Tlie Collie." By Hugh Dalziel. Paper, illustrated. ... 50 — "The Diseases of Dogs." Causes, symptoms and treatment. By Hugh Dalziel. Illustrated. Paper, 50c. Cloth, 1 CO — "Diseases of Horses." Paper 50 — " The Fox Terrier." By Hugh Dalziel. Paper, 50 ; clo.l 00 — "The Greyhound." Cloth, illus 1 OO — " The St. Bernard." Cloth, lUuitrated ,,,.,.,,,..:[ qQ VANA. "Tables in Comparatiye Phygiology," By Prof. C. L. Dana, M.D. Chart, 17 x 17 26 DANCE. "Veterinary Tablet." By A. A. Dance.' Chart, 17 X 24, mounted on linen, folded in a cloth case for the pocket, size 3 3-4 x 6 1-2. Shovps at a glance the eynopsis of the diseases of horses, cattle and dogs ; with their cause, symptoms and cure 75 DE BBUIN. (*)" BoTine Obstetrics." By M. G. De Bruin Instructor of Obstetrics at the Slate Veterinary School in Utrecht. Translated by W. E. A. Wyman, formerly Professor of Veterinary Science at Clemson A. & M. College, and Veterinarian to the South Carolina Experiment Station. Cloth, size 6x9, 382 77 illustrations 5 00 Synopsis of the Es»sential Features of tbe Work 1. Authorized translation. 2. The only obstetrical work which is up to date. 3. Written by Europe's leading authority on the subject. 4. Written by a man who has practiced the art a lifetime. 5. Written by a man who, on account of his eminence as bovine practitioner and teacher of obstetrics, was selected by Prof. Dr. FrOhner and Prof. Dr. Bayer (Berlin and Vienna), to discuss bovine obstetrics both practically and scientifically. 6. The only work containing a thorough differential diaK- nosis of arte and post partmn diseases. 7. The only work doing justice to modern obstetrical surgery and therapeutics. 8. Written by a man whose practical suggestions revolu- tionized the teaching of veterinary obstetrics even in the great schools of Europe. 9. The only work dealing fully with the now no longer obscure contagious and infectious diseases of calves. 10. Absolutely original and no compilation. 11. The only work dealing fully with the difficult problem of teaching obstetrics in the colleges. 12. The only work where the practical part is not over- shadowed by theory. ... A veterinarian, particularly if his location brings him in contact with obstetrical practice, who makes any pretence toward beinvc scientific and in possession of modern knowledge upon this subject, will not be without this excellent work, as it is really a very valuable treatise.— Pro/. Roscoc R. BcU, iu the American Veterinary Review. , In translating into English Professor De Bruin's excellent text- book on Bovine Obstetrics, Dr. Wyman has laid British and American veterinary surgeoTis and students under a debt of gratitude. The works represents the happy medium between the booklets which are adapted for cramming purposes by the student, and the ponderofus tomes which, although useful to the teacher, are not exactly suited to the requirements of the everyday practitioner . . . We can strongly recommend the work to veterinary students and practitioners.— The Journal uf Coi)\parative Pathology and Therapeutics. DOLLAR. f*)" Diseases of Cattle, Slieep, Goats and Swine." By G. Moussu and Jno. A. W. Dollar, M.Il.C.V.S. Size 6x9 1-2, 785 pages, 329 illustrations in the text and 4 full page plates 8 75 — (t)'*A. Hand-book of Horse-Shoeing," with Introductory chapters on the anatomy and physiology of the hor.se'8 foot. By Jno. A. W. Dollar, M.E.C.V.S., with the collaboration of Albert Wheatley, F.E.C.V.S. gioth, size 6x8 1-2, 433 pa^'es, 4C6 illustrations . .4 76 DOLLAK (continued) — (t)* 'Operative Tochnuiue." Volume 1 of "The Practice of Veterinary Surgery." Cloth, size 6 3-4 x 10, 264 pages, 272 illustrations 3 75 — *' General Suri^ery.*' Volume 2 of "The Practice of Veter- inavy Surgery." In preparation. — (f)" Regional Veterinary Surgery." Volume 3 of "The Practice of Veterinary" Surgery." By Drs. Jno. A. W. Dollar and H. MoUer. Cloth, size 6 1-2 x 10 853 and xvi pages, 315 illustrations 6 25 — "Catliot's Clinical Veterinary Medicine and Surgei'y." See " Cadiot." — "Cadiot's Roaring in Horses." See " Cadiot." DUN. "Veterinary Medicines, their Actions and Uses." By Finlay Dun, V.S., late lecturer on Materia Medica and Dietetics at the Edinburgh Veterinary College, and Examiner in Chemistry to the Eoyal College of Veterinary Surgeons. Edited by James Macqueen, F.R.C.V.S. Tenth revised English edition. Cloth, size 6x9 3 75 FLEMING. " The Contagious Diseases of Animals." Their influence on the wealth and health of nations and how they are to be combated. Paper, size 5x7 1-2, 30 pages 25 — " Human and Animiil Variolae." A Study in Comparative Pathology. Paper, size 5 1-2x8 1-2, 61 pages 25 — ' "Parasites and Parasitic Diseases of the Domesticated Animals." By L. G. Neumann. Translated by Dr. Fleming. See " Neumann." — "Operative Veterinary Surgery." Vol. I, by Dr. Geo. Fleming, M.R.C.V.S. This valuable work, one of the most practical treatises yet issued on the subject in the English language, is devoted to the common opera- tions of Veterinary Surgery ; and the concise descrip- tions and directions of the text are illustrated with numerous wood engravings. Cloth, size 6x9 1-4, 285 and xviii pages, 343 illustrations 2 75 (*)Vol. II, edited and passed through the press by W. Owen Williams, F.R.C.V.S. Cloth, size 6x9 1-4, 430 and xxxvii pages, 344 illustrations 3 25 — " Roaring in Horses." By Dr. George Fleming, F.R.C.V.S. Its history, nature, causes, prevention and treatment. Cloth, size 5 1-2x8 3-4, 160 pages, 21 engravings, 1 colored plate 1 50 — " Veterinary Obstetrics." Including the Accidents and Dis- eases incident to Pregnancy, Parturition, and the Early Age in Domesticated Animals. By Geo. Fleming. F.R.C.V.S. Cloth, size 6x8 3-4, 758 pages, iUus.6 25 OOTTHIEL. n"A Manual of General Histology. By Wm. S. Gottheil, M.D., Professor of Pathology in the American Veterinary College, New York; etc., etc. Histology is the basis of the physician's art, aB Anatomy is the foundation of the surgeon's science. Only by knowing the processes of life can we under- stand the changes of disease and the action of remedies; as the architect must know his building materials, so must the practitioner of medicine know the intimate structure of the body. To present this knowledge in an accessible and simple form has been the author's task. Second edition revised. Cloth, size 5 1-2 x 8, 152 pages, 68 illustrations. . .1 00 GBESSWELL. "Diseases and Disorders of the Horse." A Treatise on Equine Medicine and Surgery, being a contribution to the science of comparative pathology. By Albert, Jas. B. and Geo. Gresswell. Cloth, size 5 3-4x8 3 4, 227 pages, illustrated. 1 75 — " The Bovine Prescriber." For the use of Veterinarians and Veterinary Students. Second edition, revised and enlarged, by James B. and Albert Gresswell, M.R.C.V.S. Cloth, size, 5 X 7 1-2, 102 pages 75 — "The Equine Hospital Prescriber." For the use of Veter- inary Practitioners and Students. Third edition re- vised and enlarged, by Drs. James B. and Albert Gresswell, M.R.C.V.S. Cloth, size 5 x 7 1-2, 165 pages 76 — Manual of "The Theory and Practice of Equine Medicine." By James B. Gresswell, F.R.C.V.S., and Albert Gresswell, M.R.C.V.S. Second edition revised. Cloth, size 5 1-4x7 1-2, 539 pages 2 75 — (t) "Veterinary Pharmacopseia and Manual of Comparative Therapy." By George and Charles Gresswell, with descriptions and physiological actions of medicines, by Albert Gresswell. Second edition revised and enlarged. Cloth, 6x8 3-4, 457 pages 3 50 HASSLOCH. " A Compend of Veterinary Materia Medica and Therapeutics." By A. C. Hassloch, V.S., Lecturer on Materia Medica and Therapeutics, and Professor of Veterinary Dentistry at the New York College of Veterinary Surgeons and School of Compa- rative Medicine, N. Y. Cloth, size 5 1-4x7 1-2, 225 pages 1 50 HEATLEY. " The Stock Owner's Guide." A handy Medi- cal Treatise for every man who owns an ox or cow. By George S. Heatley, M.R.C.V.S. Cloth, size 5 1-4 X 8, 172 pages 1 26 HILL. (I)" The Diseases of the Cat." By J. Woodroffe Hill, F.R.C.V S. Cloth, size 5 14x7 1-2, 1!!3 pages, illustrated 1 25 Written from the experience of many years' prac- tice and close pathological research into the maladies to which our domesticated feline friends are liable — a subject which it must be admitted has not found the prominence in veterinary literature to which it is undoubtedly entitled. — "The Management and Diseases of the Doff" By J. Woodroffe Hill, F.R.C.V.S. Cloth, size 5x7 1-2, extra fully illustrated . HINEBAUCH. "Veteriuary Dental Surgery." By T. D. Hinebauch, M.S.V.S. For the use of Students, Prac- titioners and Stockmen. Cloth, size 5 1-4 x 8, 256 pages, illustrated 2 00 HO ARE. (*)"A Manual of Veterinary Therapeutics and Pharmacology." By E. Wallis Hoare. F.R.C.V.S. Cloth, size 5 1-4x7 1-4, xxvi plus 780 pages 4 75 HOBDAY, (t)" The Castration of Cryptorchid Horses and the Ovariotomy of Troublesome Mares." By Frederick T. G. Hobday, F.R.C.V.S. Cloth, size 6 3-4 x 8 3-4, 1C6 pages, 34 illustrations 1 75 HUNTING, (f) The Art of Horse-shoeing. A manual for Horseshoers. By William Hunting, F.R.C.V.S., ex-President of the Royal College of Veterinary Sur- geons. One of the most up-to-date, concise books of its kind in the English language. Cloth, size 6x9 1-4. 126 pages, 96 illustrations 1 00 JENKINS. (*)" Anatomical and Physiological Model of the Cow." Half life size. Composed of superposed plates, colored to nature, showing internal organs, muscles, skeleton, etc., mounted on strong boards, with explanatory text. Size of Model opened, 10 ft. X 3 ft., closed 3 ft. x It ft 12 00 — "Anatomical and Physiological Model of the Horse." Half life size. Size of Model 38 x 41 in 12 CO These models may also be obtained in smaller sizes together with Models of the Dog, Sheep and Pig. JONES. (*)"The Surgical Anatomy of the Horse." By Jno. T. Share Jones, M.R C.V.S. Part I. To be completed in four parts. Each part — paper, $4.25 ; cloth, $5.00. Subscriptions for the four parts, pay- able in advance, paper, $15.00 ; cloth, $17.50. KOBEBT. "Practical Toxicology for Physicians and Students " By Professor Dr. Rudolph Robert. Medical Director of Dr. Brehmer's Sanitarium for Pulmonary Diseases at Goerbersderf in Silesia (Prus- sia), late Director of the Pharmacological Institute, Dorpat, Kussia. Translated and edited by L. H. Friedburg, Ph.D. Authorized Edition. Practical knowledge by means of tables which occupy little space, but show at a glance similarities and differ- ences between poisons of the same group. Also rules for the Spelling and Pronunciation of Chemical Terms, as adopted by the American Association for the Ad- vancement of Science. Cloth, 6 1-2 x 10, 201 pp.. 2 60 KOCH. "JEtiology of Tuberculosis." By Dr. E. Koch. Translated by T. Saure. Cioth, size 6x9 1-4, 97 pages 1 00 LAMBEBT. "The t}erm Theory of Disease." Bearing upon the health and welfare of man and the domesticated animals. By James Lambert, F.R.C.V.S. Paper, size 5 1-4x8 1-4, 26 pages, illustrated 25 ItAW. "Farmers' Teterinary Adriser." A Guide to the Prevention and Treatment of Disease in Domestic Animals. By Prof. James Law. Cloth, size 5 1-4x7 1-2, illustrated 3 00 LIAUTABD, (t)" Animal Castration." A concise and practical Treatise on the Castration of the Domestic Animals. The only work on the subject in the English language. By Alexander Liautard, M.D.,V.S. Having a fine portrait of the author. Tenth edition revised and enlarged. Cloth, size 5 1-4x7 1-2, 165 pages, 45 illustrations 2 00 . . . The most complete and comprehensive work on the subject in English veterinary literature.— American Agri- culturist. — **Cadiot's Exercises in Equine Surgery." Translated by Prof. Bitting and edited by Dr. Liautard. See " Cadiot." — "A Treatise on Surgical Therapeutics of the Domestic Animals." By Prof. Dr. P. J. Cadiot and J. Almy, Translated by Prof. Liautard. See " Cadiot." — " How to Tell the Age of the Domestic Animal." By Dr. A. Liautard, M.D., V.S. Standard work upon this subject, concise, helpful and containing many illustrations. Cloth, size 5x7 1-2, 35 pages, 42 illustrations 50 ~ "Lameness of Horses and Diseases of the Locomotory Apparatus." By A. Liautard, M.D.,V.S. This work is the result of Dr. Liautard's many years of experi- ence. Cloth, size 5 1-4x7 1-2, 314 pages 2 63 LIAUTARD (continued). — (*)" Manual of Operative Veterinary Surgery." By A. Liautard, M.D., V.M. Engaged for years in ttiework of teaching this special department of veterinary medicine, and having abundant opportunities of realizing the difllculties which the student who earnestly strives to perfect himself in his calling is obliged to encounter, the author formed the deter- mination to facilitate his acquisition of knowledge, and began the accumulation of material by the com- pilation of data and arrangement of memorandum, with the recorded notes of his own experience, the fruit of a long and extended practice and a careful study of the various authorities who have illustrated and organized veterinary literature. Revised edition, with complete index. Cloth, size 6 1-4 x 9, xxx and 803 pages, 5G3 illustrations 5 00 — **Pellerm's Median Neurotomy in the Treatment of Chronic Tendinitis and Periostosis of the Fetlock." Translated by Dr. A. Liautard. See " Pellerin." — "Vade Mecum of Equine Anatomy." By A. Liautard, M.D.V.S. For the use of advanced students and veterinary surgeons. Third edition. Cloth, size 5x7 1-2, 30 pages and 10 full page illustrations of the arteries . 2 00 — Zundel's " The Horse's Foot and Its Diseases." See " Zundel." LONG. " Bool£ of the Pig." Its selection, Breeding, Feeding andManagement. Cloth 4.00 LOWE. (t)" Breeding Raceliorses by the Figure System." Compiled by the late C. Bruce Lowe. Edited by William Allison, " The Special Commis- sioner," London Sportsman, Hon. Secretary Sporting League, and Manager of the International Horse Agency and Exchange. With numerous fine illustra- tions of celebrated horses. Cloth, size 8 x 10, 262 pages • 7 50 LUDLOW. "Science in the Stable"; or How a Horse can be Kept in Perfect Health and be Used Without Shoes, in Harness or under the Saddle. With the Reason Why, Second Edition. By Jacob R. Ludlow, M.D. Late Staff Surgeon, U. S. Army. Paper, size 4 1-2x 5 3-4, 166 pages 50 LUPTON. "Horses: Sound and Unsound," with Law relating to Sales and Warranty. By J. Irvine Lupton. F.R.C.V.S. Cloth, size 6 3-4 x 7 1-2, 217 3 illustrations 1 25 M'FADTEAN. (f) " Anatomy of the Horse." Second edition completely revised. A Dissection Guide. By John M'Fadyean, M.B., B.Sc, F.R.S.E. Cloth, size 6 X 8 3 4, 388 pa^es, illustrated 5 tu This book is intended for Veterinary students, and offers to them in its 48 full-page colored plates, 54 illustrations and excellent text, a valuable and practical aid in the study of Veterinary Anatomy, especially in the dissecting room. — ** Comparatiye Anatomy of the Domesticated Animals." By J. M'Fadyean. Profusely illustrated, and to be issued in two parts. Part I— Osteology, ready. Size 5 1-2x8 1-2, 166 pages, 132 illustratione. Paper, 2 50; cloth 2 75 (Part II in preparation.) MAGNEB. "Standard Horse and Stock Book." By D. Magner. Comprising over 1,000 pages, illustrated with 175G engravings. Leather binding. 6 10 MILLS. "How to Keep a Dog in the City." By Wesley Mills, M.D., D.V.S. It tells how to choose, manage, house, feed, educate the pup, how to keep him clean and teach him cleanliness. Paper, size 5x7 1-2, 40 pages 25 MOHLER. "Handbook of Meat Inspection." By Robert Ostertag, M.D. Translated by Eai-ley Vernon Wilcox, A.M., Ph.D. With an introduction by John E. Mohler, V.M.D., A M. See " Ostertag" MOLLER — DOLLAR. (f) "Regional Veterinary Surgery." See '^ Dollar." MOSSELMAN.LIENAUX. "Manual of Veterinary Microbiology." By Professors Mosselman and Lienaux, Nat. Veterinary College, Cureghem, Belgium. Translated and edited by R. R. Dinwiddle, Professor of Veterinary Science, College of Agriculture, Arkansas State University. Cloth, size 5 1 2 x 8, 342 pages, illustrated 2 00 MOUSSV. n" Diseases of Cattle, Sheep, Goats and Swine." See " Dollar." NEUMANN. (*)"A Treatise on Parasites and Parasitic Diseases of the Domesticated Animals." A work to which the students of human or veterinary medi- cine, the sanitarian, agriculturist or breeder or rearer of animals, may refer for full information regarding the external and internal Parasites— vegetable and animal — which attack various species of Domestic Animals. A Treatise by L. G. Neumann, Professor at the National Veterinary School of Toulouse. Translated and edited by Geo. Fleming, C.B., LL.D.. F.R C.V.S. Second edition, revised and edited by James Macqueen, F.R.C.V.S., Professor at the Royal Veterinary College, London. Cloth, size 6 3-4 x in, xvi + 698 pages, 365 illuatratioaa 6 76 NOCAItiy. *' The Animal Tuberculoses, and their Relation to Human Tuberculosis." By Ed. Nocard, Prof, of the Alfort Veterinary College. Translated by H. Scurfield, M.D. Ed.,Ph. Camb. Cloth, 5 x7 1-2, 143 pages.,! 00 Perhaps the chief interest to doctors of human medicine in Professor Nocard's book lies in the demonstration of the small part played by heredity, and the great part played by contagion in the propa- gation of bovine tuberculosis. NUNN. (*)"■ Veterinary Toxicology." By Joshua A. Nunn, F.R.C.V.S. The study of toxicology is intimately blended with other biological sciences, particularly physiology and chemistry, both of which it on many occasions overlaps. A carefully arranged and com- plete index is given In the front of the volume. Cloth, size 6x83-4, vii + 191 pages 1 75 OSTEBTAG. C) " Handbook of Meat Inspection." By Robert Ostertag, M.D. Authorized Translation by Earley Vernon Wilcox, A.M., Ph.D. With an intro- duction by John E,. Mohler, V.M.D., A.M. The work is exhaustive and authorative and has at once become the standard authority upon the subject Second edition, revised. Cloth, size 6 3-4x9 3-4, 920 pages, 260 illustrations and 1 colored plate 7 50 PALLIN. (*) " A Treatise on Epizootic Lymphangitis." By Capt. W. A. Pallin, F.R.C.V.S. In this work the author has endeavored to combine his own experience with that of other writers and so attempts to give a clear and complete account of a subject about which there is little at present in English veterinary litera- ture. Cloth, size 5 3-4x8 1-2, 90 pages, with 17 fine full page illustrations 1 25 PEOLEB. " Goat Keeping for Amateurs." Paper, 5x7i, 77 pages, illustrated 50 PELLEBIN. "Median Neurotomy in the Treatment of Chronic Tendinitis and Periostosls of the Fetlock." By C. Pellerin, late repetitor of Clinic and Surgery to the Alfort Veterinary School. Translated, with Addi- tional Facts Relating to It, by Prof. A. Liautard, M.D., V.M. Having rendered good results when performed by himself, the author believes the operation, which coQsists in dividing the cubito-plantar nerve and in excising a portion of the peripherical end, the means of improving the conditions, and consequently the values of many apparently doomed animals. Agricul- ture in particular will be benefited. The work is divided into two parts. The first covers the study of Median Neurotomy itself ; the second, the exact relations of the facts as observed by the author. Boards, 6x9 1-2, 61 pages, illustrated . . 1 00 PETERS. " A Tuberculous Herd— Test nith Tuber- culin." By Austin Peters, M. R. C. V. S., Chief Inspector of Cattle for the New York State Board of Health during the winter of 1892-93. Pamphlet. . . .25 REYNOLDS. "An Essay on the Breeding and Manage- ment of Draught Horses." By R. S. Reynolds, M.R.C.V.S. Cloth, size 5 1-2x8 3-4, 104 pages. .1 4u ROBERGE. " The Foot of the Horse," or Lameness and all Disea.ses of the Feet traced to an Unbalanced Foot Bone, prevented or cured by balancing the foot. By David Roberge. Cloth, size G x 9 1-4, 308 pages, illustrated 5 00 I^ESSIONS. (*)" Cattle Tuberculosis," a Practical Guide to the Agriculturist and Inspector. By Harold Sessions, F.R,C.V.S., etc. Second edition. Size 5x7 1-4, vi + 120 pages 1 00 The subject can be understood by those who have to deal particularly with it, yet who, perhaps, have not had the necessarj' training to appreciate technical phraseologj'. SEWELL. "The Examination of Horses as to Sound- ness and Selection as to Purchase." By Edward Sewell, M.R.C.V.S. Paper, size 51-2x8 1-2, 86 pages, illastrated with 8 plates in color 1 50 It is a great advantage to the business man to know something of the elements of law, and nobody ought either to buy or own a horse who does not know something about the animal. That something this book gives, and gives in a thoroughly excellent way SMITH. (*) *♦ A Manual of Yeterinary Physiology." By Vet. Capt. F. Smith, C.M.S., M.R.C.V.S.. Examiner in Physiology, Royal College of Veterinary Surgeons, author of "A Manual of Veterinary Hygiene." A completely revised and enlarged edition just pub- lished. Cloth, 6x8 3-4, 720 pp, 102 illust'ns 4 25 The whole book lias been carefully revised and brought up to date. All the important advances of tlie last few years have been embodied. The chapter on the nervous system has been specially revised by Prof. Sherrington, wliose remarkable work on the "spinal dog" has been introduced. A special point is made of the bearing of physiology on pathology, and the utilization of physiology to the better understanding of every-day practice. The book is written by a veterin- ary surgeon for veterinary practitioners and students, and is the only work in the English language which can claim to be purely veterinary. — (*)*^Manual of Yeterinary Hygiene." Third edition revised. Cloth, size 5 1-4x7 1-2, xx + 1036 pages, with 255 illustrations 4 7ft Recognizing the rapid advance and extended field of the subject since the previous issue, the author has entirely re-written the work and enlarged its scope, whi«h is brought thoroughly up to date. Con- tains over 600 more pages than the seoond edition. STRANGEWAT. (t)"Teteriiiary Anatomy-w" Edited by I. Vaughan, F.L.S., M.R.C.V.S. New edition revised. Cloth, size 6 1-4x9 1-2, 625 pages, 224 illus 5 00 SUSSDORF. " Six Large Colored Wall Diagrams." By Prof. Sussdorf, M.D. (of Gottingeii). Text translated by Prof. W. Owen Williams, of the New "Veterinary College, Edinburgh. Size, 44 inches by 30 inches. 1.— Horse. 4.— Ox. 2.— Mare. 5.— Boar and Sow. 3.— Cow. 6.— Dog and Bitch. The above are printed in eight or nine colors. Showing the position of the viscera in the large cavities of the body. Price, unmounted 1 75 each •' mounted on linen, with roller... 3 50 " VAN MATEB, <' A Text Book of Veterinary Oph- tlialmology." By George G. Van Mater, M.D., D.V.S., Professor of Ophthalmology in the American Veterinary College; Oculist and Auristto St. Martha's Sanitarium and Dispensary ; Consulting Eye and Ear Surgeon to the Twenty-sixth Ward Dispensary ; Eye and Ear Surgeon, Brooklyn Eastern District Dispen- sary, etc. Illustrated by one chromo lithograph plate and 71 engravings. Cloth, 6x9 1-4, 151 pages.. .3 00 . . . We Intend to adopt this valuable work as a text book.— B. J. Creely, D.V.S., Dean of the San Francisco Veterinary College. VETERINARY DIAGRAMS in Tabular Form. Size, 28^ in. x 22 inches. Price per set of five 4 00 Mounted and folded in case 7 «0 Mounted on roller and varnished 10 00 No. 1. 'The External Form and Elementary Ana- tomy of the Horse." Eight colored illustrations — 1. External regions ; 2. Skeleton ; 3. Muscles (Superior Layer) ; 4. Muscles (Deep Layer) ; 5. Respiratory Ap- paratus ; 6. Digestive Apparatus ; 7. Circulatory Ap- paratus ; 8. Nerve Apparatus ; with description 1 25 Mounted on roller and varnished 2 25 No. 2. "The Age of Domestic Animals." Forty-two figures illustrating the structure of the teeth, indicat- ing the Age of the Horse, Ox, Sheep, and Dog, with full description 75 Mounted on roller and varnished 2 00 No. 3. " The Unsoundness and Defects of the Horse." Fifty figures illustrating— 1. The Defects of Confor- mation ; 2. Defects of Position ; 3. Infirmities or Signs of Disease ; 4. Unsoundnesses ; 5. Defects of the Foot ; with full description 75 Mounted on roller and varnished 2 00 VETERINARY DIAGRAMS (continued). No. 4. "The Shoeing of the Horse, Mule and Ox." Fifty figures descriptive i>f the Anatomy and Physio- logy of the Foot and of Horse-shoeing 75 Mounted on roller and varnished 2 00 No. 5. ''The Elementary Anatomy, Points, and But- cher's Joints of the Ox." Ten colored illustrations —1. Skeleton ; 2. Nervous System ; 3. Digestive System (Right Side) ; 4. Respiratory System ; 6, Points of a Fat Ox ; 6. Muscular System ; 7. Vascular System ; 8. Digestive System (Left Side) ; 9. Butcher's Sections of a Calf ; 10. Butcher's Sections of an Ox ; with full description 1 25 Mounted on roller and varnished 2 25 WALLET. " A Practical Guide to Meat Inspection," By Thomas Walley, M.R.C.V.S., late principal of the Edinburgh Royal (Dick) Veterinary College; Pro- fessor of Veterinary Medicine and Surgery, etc. Fourth Edition, thoroughly revised and enlarged by Stewart Stockman, M.R.C.V.S., Professor of Pathology, Lecturer on Hygiene and Meat Inspection at Dick Veterinary College, Edinburgh. Cloth, size 5 1-2x8 1-4, with 45 colored illus., 295 pages 3 00 An experience of over 30 years in his profession and a long official connection (some sixteen years) with Edinburgh Abattoirs have enabled the author to gather a large store of information on the subject, which he has embodied in his book. While Dr. Stockman is indeed indebted to the old for much useful information, this up-to- date work will hardly be recognized as the old '* Walley 's Meat Inspection." WILCOX. (*)'' Handbook of Meat Inspection." By Robert Ostertag, M.D. See " Ostertag." WILLIAMS. "Principles and Practice of Veterinary Medicine." Author's edition, entirely revised and illustrated with numerous plain and colored plates. Bv W. Williams, M.R.O.V.S. Cloth, size 5 3-4x8 3-4, 865 pages 7 50 '* Principles and Practice of Veterinary Surgery." Author's edition, entirely revised and illustrated with numerous plain and colored plates. By W. Williams, M.R.O.V.S. Cloth, size 6 1-2x9 1-4, 756 pages .7 50 THE MOST COMPLETE, PROGRESSIVE AND SCIENTIFIC BOOK ON THE SUBJECT IN THE ENGLISH LANGUAGE (•) WINSLOW, "Veterinary Materia Medica and Therapeu- tics." By Kenelm VVinslow, B.A.S., M.D.V., M.D., (Harv.) ; formerly Assistant Professor of Therapeutics in tlie .Veterinary Sciiool of Harvard University ; Fellow of tiie Massachusetts Medical Society ; Surgeon to the Newton Hospital, etc. Fifth Edition, Revised and Enlarged Cloth, size 6 1-4x9 1-4, x + 804 pages 6 00 In accordance with the hitherto expressed desire of the author and publishers to keep this work at its highest point of efficiency, it has been deemed incumbent upon them to again present a new and revised edition— the fourth edition of 1906 being exhausted. In the present revision the most notable feature is the substitution of a section on Condensed Treatment of Diseases of the Domestic Animals for the Index of Diseases and Remedial Measures, at the end of the book. In the preparation of this matter, very considerable time and pains have been taken to render this section a reflection and epi- tome of all that is most modern and progressive in veterinary thera- peutics. Special indications for treatment, including drugs and therapeutic agents other than drugs, in the different phases and stages of all the important diseases of the domestic animals are to be found. These dis- eases embrace not only medical and surgical disorders, but those of the EYE, SKIN and EAR. If the attempt has been in any degree successful, this new edition to the book should prove one of its most valuable features both to practitioners and students. Moi'eover, many changes have been made in the text in consonance with recent advances in our knowledge of the action of drugs. — (*) " The Production and Handling- of Clean Milk." A complete, plain, practical and authoritative guide to the production and distribution of clean milk for farmers, health officers, milk inspectors, students of agriculture and dairying, country gentlemen, physi- cians and others interested in matters pertaining to dairying and hygiene. The book also contains a general outline of a scheme for the control, supervi- sion and inspection of a city milk supply. Cloth, 6 3-4 X 9 3-4, xii plus 207 pp. many illustrations, in- cluding 1 colored and 15 full page plates 2 50 WYMA.N. (*)"BoTine Obstetrics." By M. G. De Bruin. Translated by W. E. A. Wyman, M.D.V.,V.S. See also " De Bruin." — (*)" Catechism of tlie Principles of Veterinary Surgery." Bv W. E. A. Wyman, M.D.V.,V.S. Cloth, size 6x9, 321 pages 3 50 Concerning ibis ne>v work attention is called to the follo^viui^ points : 1.— It discusses the subject upon the basis of veterinary investigations. 2.— It does away with works on human pathology, histology, etc. 3.— It explains each question thoroughly both from a scientific as well as a practical point of view. 4.— It is writen by one knowing the needs of the student. WYMAN (Continued) 5.— It deals exhaustively with a chapter on tumors, heretofore utterly neglected in veterinary pathology. 6.— The only work in English specializing the subject. 7.— The only work thoroughly taking into consideration American as well as European investigations. 8.— Offering practical hints which have not appeared in print, the result of large city and country practice. — (t/' The Clinical Diagnosis of Lameness in tlie Horse." By W. E. A. Wyman, D.V.S., formerly Professor of Veterinary Science, Clemson A. & M, College, and Veterinarian to the South Carolina Experiment Station. Cloth, size 6x9 1-2, 182 pp., 32 illus. . . .2 50 (t)"Tibio-peroneal Neurectomy for the Relief of Spavin Lameness." By W. E. A. Wyman, M.D.V., V.S. Boards, size 6 s 9, 30 pages, illustrated....' 50 Anyone wanting to perform this operation should procure this little treatise ; he will tind it of considerable help.— TTie Veterinary Journal. ZUILL. "Typhoid Fever; or Contagions Inflnenia in the Horse." By Prof. W. L. Zuill, M.D.,D.V.8. Pamphlet, size 6x9 1-4, 29 pages 25 ZUNDEL. "The Horse's Foot and Its Diseases." By A. Zundei, Principal Veterinarian of Alsace Lorraine. Translated by Dr. A. Liautard, V.S. Cloth, size 5x7 3-4, 248 pages, illustrated 2 00 Any booh sent prepaid for the price WILLIAM R. JENKINS CO. 851 and 853 Sixth Avenue, NEW YORK.