■ 1 
 
 
 ^^ \?. 
 
TUFTS UNIVERSITY LIBRARIES 
 
 3 9090 014 531 723 
 
 I 
 
 
 Webster Family Library of Veterinary Medicine 
 Cummings Sciiool of Veterinaiv Medicine at 
 tutts University 
 ■200 VVestboro Road 
 Nortli Grafton, MA 01536 
 
VADE MECUM 
 
 OF 
 
 EQUINE ANATOMY. 
 
 FOR THE USE OF ADVANCED STUDENTS 
 AND VETERINARY SURGEONS. 
 
 BY 
 
 A. LIAUTARD. M.D.,V,S. 
 
 5 T ik/IJ 
 
 Pro/esso7' of Comparative Anatorny to the American 
 Veterinary College, Etc., Etc. 
 
 NEW YORK : 
 Published at the American Vetebinary College, 141 W. Fifty-fourth St. 
 
 1879. 
 
Press of 
 
 CHAUNCEY HOLT, 
 
 119 and 121 Nassau Street, 
 
 New York. 
 
 COPYKIGHT, 1879, 
 BY 
 
 A. LIAUTARD, M.D.,V.S. 
 
TO 
 
 GEORGE FLEMING, F.E.C.V.S. 
 
 FOR HIS UNriRING EFFORTS IX ADVANCING THE CAUSE OF 
 
 VETERINARY SCIENCE, THIS LITTLE VOLUME 
 
 IS RESPECTFULLY DEDICATED, BY 
 
 THE AUTHOR. 
 

CONTENTS 
 
 PAGE. 
 
 IntPwOductoey 9 
 
 Osteology (Generalities) 10 
 
 Myology, " U 
 
 Syjjdesmology, " 12 
 
 Splanchnology, " 14 
 
 Angeiology, " 15 
 
 Neurology, " 16 
 
 EXTREMITIES. 
 
 AntePvIor Leg 17 
 
 Osteology 17 
 
 Syndesmolog Y 21 
 
 Myology 24 
 
 Angeiology 31 
 
 Neurology 35 
 
 Appendages of the Digital Region 40 
 
 Posterior Leg 45 
 
 Osteology ! 45 
 
 Syndesmology 50 
 
 Myology 52 
 
 Angeiology 59 
 
 Neurology 63 
 
 HEAD. 
 
 Osteology 67 
 
 Syndesmology 74 
 
 Myology 74 
 
 Splanchnology 77 
 
 Nasal Cavities 77 
 
 Buccal Cavity 78 
 
CONTENTS. 
 
 PAGE. 
 
 Eye 84 
 
 Ear 88 
 
 Cranium 91 
 
 Enceplialon 92 
 
 Pharynx 97 
 
 Larynx 98 
 
 Salivary Glands 100 
 
 Angeiology 103 
 
 Netjeology 109 
 
 TRUNK. 
 
 Osteology 117 
 
 Neueology 118 
 
 NECK. 
 
 Osteology : 119 
 
 S yndesmolog Y 120 
 
 Myology 121 
 
 Splanchnology 126 
 
 Trachea 126 
 
 (Esophagus 127 
 
 Thyroid Gland 128 
 
 Angeiology ^ 128 
 
 Neueology 129 
 
 THORAX. 
 
 Osteology 131 
 
 Syndesmology 134 
 
 Myology 1 35 
 
 Splanchnology 1 39 
 
 Pleura 139 
 
 Bronchia 139 
 
 Lungs , 140 
 
 Heart 141 
 
 Angeiology 144 
 
 Neueology 150 
 
CONTENTS. 
 
 PAGE. 
 
 DIAPHRAGMATIC REGION. 
 
 Myology 151 
 
 Angeiolog y 151 
 
 ABDOMEN. 
 
 Osteology 152 
 
 s yndesmology 152 
 
 Myology 153 
 
 Splanchnology 157 
 
 Peritoneum 157 
 
 Stomach 158 
 
 Liver 159 
 
 Spleen 160 
 
 Pancreas 161 
 
 Kidneys 162 
 
 Ureters •. 162 
 
 Ovaries 163 
 
 Oviducts 163 
 
 Uterus 163 
 
 Intestines 164 
 
 Angeiology 167 
 
 Neurology 174 
 
 PELVIS. 
 
 Osteology 176 
 
 s yndesmology 177 
 
 Myology I77 
 
 Splanchnology I77 
 
 Rectum I77 
 
 Anus .'...178 
 
 Bladder ^ 178 
 
 Vagina I79 
 
 Vulva 179 
 
 Angeiology 179 
 
 Neueology 183 
 
CONTENTS. 
 
 PAGE. 
 
 CAUDAL REGION. 
 
 Osteology 183 
 
 s ynde8m0l0g y 183 
 
 Myology 183 
 
 Angeiology 184 
 
 Neurology 184 
 
 APPENDIX. 
 
 Genital Organs of Male 185 
 
 Female 190 
 
 Table of Arterial Subdivision 192 
 
 Bones, (centers of ossificationj 197 
 
PREFACE 
 
 In presenting to the veterinary profession of America tliis Vade 
 Mecum of Equine Anatomy, I fully appreciate the difficulties 
 whi ch must beset its introduction, by reason of the unbounded 
 popularity of Chauveau's and Fleming's excellent works upon 
 the subject, and it is not issued with the hope that they shall 
 thereby be supplanted, but that it may fill a vacancy long existing. 
 
 During the years I have devoted to the teacliing of veterinary 
 anatomy, the fact has grown apace, that advanced students, and 
 practitioners as well, have felt the need of an abridged work in 
 which thej could, without the loss of time, review the descriptive 
 anatomy of a region. 
 
 It was in view of this want that I assumed the responsibility 
 of attempting to supply the deficiency, and while the reader will 
 find the text of Chauveau and Fleming has been closely followed, 
 there is presented an arrangement of the subject-matter correspond- 
 ing to my adopted mode of lecturing. 
 
 If then, this little volume shall prove a saving of time to students 
 reviewing their studies, and serve to refresh the memory of the 
 busy practitioner who is about to operate, it will have accom- 
 plished all the author could desire. 
 
 A. LIAUTARD. 
 
 New York. N'ov. 1878. 
 
VADE MECUM 
 
 OK 
 
 EQUINE ANATOMY. 
 
 CHAPTER I. 
 
 INTTRODUCTORY. 
 
 Definition. — Anatomy is the Science of Structure, 
 
 Division. — Descriptive, General, Microscopical, Hu- 
 man, Yeterinary, Comparative, Surgical, Topographi- 
 cal, Vegetable, Animal, Special. 
 
 Organs. — Are the instruments of life. 
 
 Apparatus. — A collection of organs for the perform- 
 ance of one function. 
 
 Division: — Apparatus of Locomotion, Digestion, 
 Respiration, Circulation, Innervation, Urinary Depura- 
 tion, of different Senses, and of Generation. 
 
10 EQUINE ANATOMY. 
 
 OSTEOLOGY. 
 
 The study of bones, or passive organs of locomo- 
 tion . 
 
 Skeleton. — Comprises all the bones of the body; 
 natural, if articulated with ligaments ; artificial, if by 
 wire or other agents. 
 
 Division : — Trunk and extremities. 
 
 Trunk. — Includes the vertebral column, with the 
 head, ribs and sternum. 
 
 Extremities — Are divided into anterior, or thoracic, 
 and posterior, or abdominal. 
 
 The Anterior — Is divided into shoulder, arm, fore- 
 arm and digital region. 
 
 The Posterior — Into hip, thigh, leg, and digital 
 region. 
 
 Bones. — Nomenclature. — Has no base; from tlieir 
 form, as theperone; their resemblance to other objects, 
 the tibia; their position, the ribs; their use, the frontal 
 or parietal. 
 
 Situation. — Kelative 1° to the median line : single or 
 symmetrical, as the vertebrae, and double orasymetrical, 
 the bones of the limbs; or 2° to other parts of the body, 
 the radius is in front of the cubitus. 
 
 Direction. — Horizontal, vertical or oblique. 
 
 Form — is absolute : long bone, as the femur ; flat. 
 
INTRODUCTORY. 11 
 
 as the scapula ; short, as the patella ; elongated, as the 
 ribs ; or — 
 
 Kelative : triangular, as the scapula ; prismatic, 
 as the tibia. 
 
 [ r r (condyles; 
 
 M .•^, i„, ] diartlirodial: -^trochlea: 
 I I articular; ^ (facettes and head; 
 
 [^synartlirodial; denticulated; 
 
 exteexal 
 Peculiarities. 
 
 s ^ 
 
 ,. (tuberosities, crest, 
 
 _^^^^^'tic.; -^ lines, &c. 
 
 S (articular; glenoid, cotyloid; 
 
 S -< (groove, fissures, 
 
 g (nonartic; -, fossae, notches, 
 
 ( foramen. 
 
 Structure. — Tissue proper, Haversian canals, bone 
 cells, compact and spongy tissue, animal and earthy 
 matter ; periosteum, marrow, blood-vessels, nerves and 
 lymphatics. 
 
 Development. — Mucous or gelatinous matter, car- 
 tilagiiie, bone. Centres of ossirication. 
 
 MYOLOGY. 
 
 The study of muscles or active organs of locomotion. 
 
 Division. — Into those of organic life or internal 
 muscles, and of animal life or external muscles. 
 
 Size. — They are large, small and very small. 
 
 Situation. — With the median line or the other 
 organs. 
 
 Form. — Long, fusiform, conical, cylindrical, penni- 
 
12 EQUINE ANATOMY. 
 
 form, wide, elliptical, quadrilateral, triangular, etc. 
 
 Direction. — Varies : according to their axis, rectilin- 
 ear or curvilinear ; according to the plumb-line, vertical 
 or horizontal ; according to bony levers, parallel or 
 oblique. 
 
 Attachments. — Are fixed or origin, and movable 
 or insertion. 
 
 Connections. — Are with the skin, bones, muscles or 
 other organs. 
 
 Strcctdee. — Red and white fibres, cellular tissue, 
 vessels and nerves. 
 
 Uses. — Flexors, extensors, abductors, adductors or 
 rotators. 
 
 Annexes. — Such as aponeurosis of contention, serous 
 bursse, synovial sheaths. 
 
 S¥i\OESMOLOGY. 
 
 The study of joints or articulations. 
 
 Division. — Diarthrodial, or movable ; synarthrodial, 
 or immovable ; amphiarthrodial, or mixed. 
 
 Diarthrodial Joint. — Offers for study, — 
 
 Articular surfaces — Facettes, head, condyles, etc. 
 
 Cartilages of covering — Which are smooth and 
 shining. 
 
 Complementary cartilages — As the meniscus. 
 
 Ligaments. — White, being peripheric, or capsular 
 
INTRODUCTORY. 13 
 
 and funicular, as the lateral and interosseous ; or yellow, 
 all peripheric. 
 
 Synovial capsula. — A serous membrane secreting 
 tlie synovia. 
 
 Motions. — Seven : simple gliding, flexion, extension, 
 abduction, adduction, rotation and circumduction. 
 
 Classification. — Enarthrosis, with all motions, as 
 the coxo-femoral joint ; angular ginglimus, or perfect 
 hinoje, with flexion and extension, as the tibio-tarsal 
 joint ; condyloid or imperfect hinge, with flexion, 
 extension and rotation, as the femoro-tibial ; trochoid 
 or lateral ginglymus, with rotation, as the axoido-atloid ; 
 arthrodia, with simple gliding, as the carpo metacarpal. 
 
 Nomenclature. — Made from the bony pieces which 
 form them. 
 
 Synarthrodia! Joint. — Articular surfaces, irregu- 
 lar, denticulated, and on the borders or faces of flat 
 bones. 
 
 Means of union. — Interosseous ligaments and 
 periosteum. 
 
 Motions, — Very limited in young, and absent in 
 old subjects. 
 
 Classification. — Sutura vera, or dentata, as the 
 pieces of frontal bone ; sutura squammosa, as the 
 parieto-temporal joint ; sutura harmonia, as the occi- 
 pito-temporal joint ; schindylesis, mortise-like, as the 
 
14 EQUINE ANATOMY. 
 
 submaxillary and nasal bones ; gomphosis, as the teeth. 
 
 Amphiarthrodial Joint. — Articular surfaces are 
 often smooth like the diarthrodial, or rono-h and cov- 
 ered by cartilage. 
 
 Means of union. — Fibro-cartilages or menisci, and 
 peripheric ligaments. 
 
 Motions. — Limited, and varying with the thickness 
 of cartilages. 
 
 Classification. — Only one kind — the vertebral ar- 
 ticulation of the body. 
 
 SPLAXCHNOLOGY. 
 
 The study of viscerae and the annexes, or those of 
 digestion, respiration, urination and generation. 
 
 Nomenclature. — Absolute, as the liver, spleen, kid- 
 neys ; or from their form, the coecum, vagina ; their 
 situation, the intestines, epididymis; their direction, 
 the rectum; structure, the ovaries, the many leaves 
 or third stomach of ruminants ; uses — as the lungs, 
 oesophagus. 
 
 Number. — They are generally single in digestive 
 organs, and double in others. 
 
 Form — Varies ; are generally asy metrical. 
 
 Situation. — In the splanchnic cavities ; sometimes 
 outside of them. 
 
INTRODUCTORY. 15 
 
 A.\GEI0L0G1. 
 
 Study of vascular system, arteries, veins and lym- 
 phatics. 
 
 Arteries. — They form two systems, the pulmonary 
 and .aortic. 
 
 General form. — Dycotyledonic division, or two by 
 two. 
 
 Form of arteries. — Kegularly c^dindrical in their 
 wliole length. 
 
 Mode of origin. — Angular, or at right, acute or 
 obtuse angle. 
 
 Situation. — Generally deeply situated. 
 
 Direction. — Straight or fluxuous. 
 
 Connections. — With veins, nerves, muscles, bones, 
 skin and cellular tissue, which form their sheatli of 
 envelopment. 
 
 Anastomoses. — By convergence, arches or transverse 
 communications. 
 
 Mode of distribution. — Terminal and collateral 
 brandies ; the terminal form the capillary subdivision. 
 
 Structure. — They have tlu'ee coats, one internal 
 serous, one middle fibro-elastic, one external cellular ; 
 they receive nerves from the ganglionary or cerebro- 
 spinal axis, also blood-vessels forming the vasa vasorum. 
 They present some anomalies. 
 
16 EQUINE ANATOMY. 
 
 IVEUROLOGY. 
 
 The study of the nervous system. 
 
 Division. — Composed of two portions, a central or 
 cerebro-spinal, and a peripheric, or the nerves. 
 
 Central portion. — Consists of the spinal marrow, 
 and the encephalon divided into ithsmus, cerebellum 
 and cerebrum. 
 
 Nerves — Form is like fasciculated cords. 
 
 Origin. — By two roots, a superior and an inferior, 
 w^hich, in uniting, present a ganglion. 
 
 Termination. — In Ijranches to the organs of animal 
 life ; and by pairs. j)erfectly alike or symmetrical, to 
 the organs of nutrition, or of vegetable life. 
 
 Structure. — A white substance, a neurilemma, 
 nerve fibres and nerve cells. 
 
 Functions. — They conduct tlie nervous currents, 
 possessing a centripetal current for the superior root, 
 and a centrifuo-al for the inferior one. 
 
CHAPTER 11. 
 
 EXTREMITIES. 
 
 ANTERIOR OR THORACIC. 
 
 OSTEOLOGY. 
 
 Shoulder. 
 
 Scapula. — Division : Two faces, three borders, tliree 
 angles. External face : Spine of omoplate or acro- 
 mion, its tuberosity, supraspinous and infraspinous 
 fossa, medullary foramen. Internal face : sub-scapular 
 fossa, two triangular surfaces. Superior border: 
 cartilage of prolongation. Anterior border : thin and 
 sharp. Posterior border: thick and concave. Cervical 
 angle, thin. Dorsal angle, thick. Humeral angle, 
 glenoid cavity, coracoid process with its tuberosity and 
 beak. 
 
 Development : two nuclei of ossification. 
 
 Arm. 
 
 Humerus. — Division : A body and two extremities. 
 Body has four faces. Anterior face : smooth. Pos- 
 
18 EQUINE ANATOMY. 
 
 terior face : smooth and round from side to side. 
 External face : has the groove of torsion, external or 
 deltoid tuberosity with crests above and below. In- 
 ternal face : has an internal tuberosity, medullary 
 foramen. Superior extremity : has a head, the great 
 and small trochanters, bicipital groove. Inferior ex- 
 tremity : shows median trochlea ; externally, a trochlea ; 
 internally, a condyle, epitrochlea, epycondyle, coronoid 
 fossa, olecranon fossa, on each side eminences and 
 cavity for ligamentous insertions. 
 
 Development : six nuclei of ossification. 
 
 Fore-arm. 
 
 Kadius. — Body, two faces : Anterior face, convex and 
 smooth. Posterior face has triangular surface, groove 
 for radio-cubital arch, eminence of implantation. 
 Superior extremity : articular surface for humerus, 
 external and internal tuberosities, coronoid process, 
 f acettes for the cubitus. Inferior extremity : articular 
 surfaces for the carpus, external and internal tuberos- 
 ities, four grooves, a rough crest behind. 
 
 Development : three nuclei of ossification. 
 
 CuBTTLTS. — Body with three faces : Anterior face, artic- 
 ulates with the radius. External face, convex. Inter- 
 nal face, concave. Three borders which separate them. 
 
EXTREMITIES. 19 
 
 Superior extremity : olecranon, its tuberosity and beak, 
 sigmoid notch. Inferior extremity : sharp. 
 Development : two centres of ossification. 
 
 Digital Region. 
 
 Carpus. — Offers six faces ; anterior face : convex ; 
 posterior face : very rough and irregular ; superior and 
 inferior faces articular ; two lateral faces : rough. It 
 is composed of seven or eight bones arranged in two 
 rows. Superior row has four bones : the trapezium 
 with two facettes, the cuneiform with five, the lunar 
 with six, the scaphoid with four. The inferior row 
 has three bones; the unciform wdth four facettes, the 
 magnum with seven, the trapezoid with five. 
 
 Development : each one centre of ossification. 
 
 Metacarpi. — Three. Principal. — Body has an an- 
 terior face, smooth and convex ; a posterior face, with 
 nutritive foramen, articular surfaces for rudimentary 
 metacarpi ; superior extremity, flat f accettes for the 
 carpus ; inferior extremity, with two condyles, median 
 spine, cavities on each side. 
 
 Development: two nuclei of ossification. 
 
 HuDiMENTARY. — Tlircc faccs ; a superior extremity : 
 articular ; an inferior, w^ith button. 
 
 Development : one nucleus of ossification. 
 
20 EQUINE ANATOMY. 
 
 Phalanges. 
 
 1. Os suFFRAcuNis. — Bodj lias two faces; anterior 
 face : slightly rough ; posterior face : flat. Has two 
 lateral borders. Superior extremity : two glenoid cav- 
 ities, median grove ; inferior extremity : two condyles, 
 median groove. 
 
 Development : two nuclei of ossification. 
 
 2. Os CORONA. — 8ix faces; anterior face: slightly 
 rough ; posterior face : elongated f acette ; lateral face ; 
 for muscular insertions ; superior face : two glenoid 
 cavities, median eminence ; inferior face : two condyles, 
 median groove. 
 
 Development: one nucleus of ossification. 
 
 3. Coffin or pedal bone. — Three faces; anterior 
 face : preplantar fissure, patilobe eminence : inferior 
 face : semilunar crest, sole, plantar fissure, plantar 
 foramen ; superior face : glenoid cavities, antero- 
 posterior eminence. Three borders ; superior border ; 
 pyramidal eminence, f acettes of insertion ; anterior 
 border : sharp and perforated ; posterior border : 
 f iCettes for navicular bone. Two extremities with 
 basilar process above, retrosal below, notch or foramen 
 between these. 
 
 Development : one nucleus of ossification. 
 Appendages : Lateral Cartilages. 
 
EXTREMITIES. 21 
 
 Sesamoids. — Two in number, three faces ; anterior 
 face : articular, concave facettes ; external face : for 
 implantation; posterior face : covered by fibro-cartilage. 
 Base for ligamentous insertion and looking down. 
 Apex looks upwards. 
 
 Development : one nucleus of ossification. 
 
 Navicular. — Anterior face : articular, two concave 
 facettes, median eminence ; posterior face : covered 
 with iibro cartilage ; anterior border : flat facette ; 
 posterior border and two extremities for ligamentous 
 attachments. 
 
 Development : one nucleus of ossification. 
 
 SYNDESMOLOGY. 
 
 ScAPULo-HUMERAL JOINT. — Eiiartlirosis. Glenoid 
 cavity of scapula and articular head of humerus. 
 Capsular ligament with two re-enforcing bands. One 
 synovial capsula. All motions. 
 
 HuMERO - RADIAL JOINT. — Augular ginglymus or 
 perfect hinge. Condyle and double trochlea of 
 humerus, glenoid cavity and double groove of radius 
 with sigmoid notch of cubitus. One anterior capsular 
 ligament and two funicular lateral, the internal the 
 longest, the external the thickest. One synovial 
 capsula with three culs de sac. Flexion and exten- 
 sion. 
 
22 EQUINE ANATOMY. 
 
 Radio-cubital joint. — Diarthrodial and synarthro- 
 dia!. For the first arthrodia, two flat facettes on each 
 bone. For the second, two rough surfaces, having the 
 radio-cubital arch between them. Two interosseous and 
 two peripheral bands. Yery limited motion in youth. 
 
 Caepal joint. — Division: Radio-carpal, carpo-carpal, 
 carpo-metacarpal, superior inter-carpal, and inferior 
 inter-carpal. 
 
 Radio-caepal joint. — Imperfect hinge. On radius, 
 outward, a wide groove, small glenoid cavity ; inward, 
 condyle with small glenoid cavity. On carpus, superior 
 face of upper row. Three posterior ligaments. One 
 synovial capsula, common to upper part of upper 
 inter-carpal joint. Flexion and extension. 
 
 Carpo-carpal joint. — Imperfect hinge. Articular 
 surfaces irregular, those of the inferior face of the 
 bones of the upper row, and those of the superior face 
 of the bones of the lower row. Three ligaments, two 
 posterior and a third outside, from the trapezium to 
 the cuneiform bone. One synovial capsula, with culs 
 de sac to lower part of superior inter-carpal, and to 
 upper part of lower inter-carpal joint. Flexion and 
 extension. 
 
 Carpo-metacarpal joint. — Arthrodia. On both 
 bones flat facettes. !Six ligaments : two anterior, two 
 posterior, two interosseous. One synovial capsula, 
 
EXTREMITIES. 23 
 
 extending to lower part of inferior inter-carpal joint. 
 Limited gliding. 
 
 Upper inter-carpal Joint. — Arthrodia. Facettes 
 of lateral faces of the bones of the first row. Six 
 ligaments : three anterior, and three interosseous. 
 
 Lower inter-carpal joint. — Arthrodia. Facettes 
 of lateral faces of the bones of the second row. Four 
 ligaments: two anterior, and two interosseous. For 
 both of these joints, more or less gliding motion. 
 
 Ligaments common to all joints, four : one anterior 
 capsular ; one posteiior capsular ; one external and 
 one internal funicular. Motions common to all the 
 carpal joints : flexion, extension, abduction, adduction, 
 and circumduction. 
 
 Metacarpo-phalangeal joint. — Perfect hinge. On 
 metacarpus, two condyles, and antero-posterior emi- 
 nence ; on lower surface, two glenoid cavities, separated 
 by median groove on os suffraginis, extended on the 
 anterior face of the large sesamoids. Six ligaments 
 for the bones of tlic lower surface ; three inferior sesa- 
 moids ; one interosseous sesamoid, two lateral. Four 
 ligaments for the metacarpus, with the bones of the 
 lower surface ; one anterior capsular ; one posterior, 
 superior sesamoid or suspensory ; two laterals. One 
 synovial capsula. Flexion and extension. 
 
 First inter-phalangeal joint. — Imperfect hinge. 
 
24: EQUINE ANATOMY. 
 
 On OS suffraginis, two condyles and antero-posterior 
 groove. On os coron^^ two glenoid cavities separated 
 bv median eminence, and extendend backwards by 
 fibro-cartilage. Two lateral ligaments ; one synovial 
 capsula. Flexion, extension and limited rotation. 
 
 Second inter-phalangeal joint. — Imperfect hinge. 
 On OS coronae, two condyles and antero-posterior 
 groove ; on os pedis, two glenoid cavities with median 
 eminence, extended upon the anterior face of the nav- 
 icular. Five ligaments : one interosseous, two anterior, 
 and two posterior lateral ; one synovial capsula. Flex- 
 ion, extension and limited rotation. 
 
 MYOLOGY, 
 
 Scapular Region. — Division : External and internal. 
 External region, four muscles. 
 
 1. Long abductor of the arm. — Synonyms. Great 
 scapulo-humeral, (G*). Teres major, (P). Great scap- 
 ulo-trochiterius, (L). Attachments : Dorsal angle of 
 the scapula, tuberosity of the acromion, external tuber- 
 osity of the humerus. Action : Abductor and rotator 
 outwards of the arm. 
 
 2. Short abductor of the arm. — Synonyms. Small 
 scapulo-humeral, (G). Teres minor, (P). Attach- 
 ments : Posterior border of the scapula, infra spinous 
 
 * G is abbreviation of Girard; P, of Percivall; L, of Ley h. 
 
fossa — to the liiimerns between the crest of the tro- 
 chiter and the deltoid imprint. Action : Abductor and 
 rotator outwards of the arm. 
 
 3. SupERSPiNATUs. — Sjuouyms. Super acromio-tro- 
 chiterius, (G). Antea spinatus, (P). Anterior spina- 
 tus, (L). Attachments : Cartilage of prolongraent of 
 the scapula, internal face of the scapular aponeurosis, 
 supraspinous fossa, anterior border and cervical angle 
 of the scapula, summit of the trochiter and trochin. 
 Action : Extensor of the arm, and tensor of the coraco- 
 radialis aponeurosis. 
 
 4. SuBSPiNATUs. — Synonyms. Sub-acromio-trochi- 
 terus, (G). Postea spinatus, (P). Posterior spinatus, 
 (L). Attachments ; Infraspinous fossa, acromion spine 
 and tuberosity, cartilage of prolongment of the scapula, 
 the internal face of scapula aponeurosis, inside the 
 convexit}' of the great trochanter to the crest of the 
 same below. Action : Abductor and rotator outwards 
 of the humerus. 
 
 Internal region, four muscles. 
 
 1. SuBscAPULARis. — Synouyms. Subscapulo-troch- 
 ineus, (G). Attachments : Sub-scapularis fossa, trochin 
 of humerus. Action : Adductor of the arm. 
 
 2. Adductor OF THE ARM. — Synonyms. Subscapulo- 
 humeralis, (G). Teres major, (P). Great scapulo- 
 hunieralis, (L). Attachments : Dorsal angle of the 
 
26 EQUINE ANATOMY. 
 
 scapula, posterior border of the subscapularis muscle, 
 internal tuberosity of the body of the humerus. Ac- 
 tion: Adductor and rotator inward of the humerus. 
 
 3. CoEAco-HUMERALis. — Coraco-bracliialis, omo-bra- 
 chialis. Synonyms. Coraco-humeralis, (P). Middle 
 scapulo-humeralis, (L). Attachments : Beak of the 
 coracoid process, above internal tuberosity of the 
 humerus, and below it towards the anterior face of that 
 bone. Action : Adductor and rotator inward. 
 
 4. ScAPULo-HUMERAL GRELE. — Syuouyms. Not de- 
 scribed by P. Tensor of capsular ligament, (L). At- 
 tachments : Rim of the glenoid cavity of the scapula, 
 and below the head of the humerus. Action : Raises 
 the capsular ligament of the joint. 
 
 Humeral Region. — Division : Anterior and poste- 
 rior. 
 
 Anterior region, two muscles. 
 
 1. Long flexor of the fore- arm. — Synonyms. Cor- 
 aco-cubitalis or coraco-radialis, (G). Flexor brachii,(P). 
 Scapulo or coraco-radialis, (L). Attachments : Tuber- 
 osity of coracoid process, supero-internal tuberosity of 
 radius and anterior extensor of the metacarpus muscle 
 by a tendinous band. Action: Flexor of the fore-arm, 
 and tensor of the antibrachial aponeurosis. 
 
 2. Short FLEXOR OF the fore- ARM. — Synonyms. Ob- 
 lique humero-cubital or humero-radial, (G). Humer- 
 
EXTREMITIES. 27 
 
 alls externus, (P) Humero-radialis, (L). Attach- 
 ments : Posterior face of tlie humerus below the head, 
 internal border of the radius under the lateral ligament. 
 Action : Flexor of the fore-arm. 
 Posterior region, five muscles. 
 
 1. Long extensor of the fore-arm. — Synonyms. 
 Long scapulo-olecranius, (G). Portion of the caput mag- 
 num of the triceps extensor brachii, (P). Long scap- 
 ulo-olecranius, (L). Attachments : Posterior border 
 of tho scapula, posterior border of the olecranon and 
 the antibrachial aponeurosis. Action : Extensor of 
 the fore-arm, and tensor of the antibrachial aponeu- 
 rosis. 
 
 2. Large extensor of the fore -arm. — Synonyms. 
 Great scapulo-olecranius, (G). Portion of the caput 
 magnum of the triceps extensor brachii, (P). Attach- 
 ments : Dorsal angle and axillary border of the scapula, 
 summit of the olecranon. Action : Extensor of the 
 fore-arm. 
 
 3. Short extensor of the fore- arm. — Synonyms. 
 Humero-olecranius externus, (G). Caput medium, (P). 
 Attachments : Curved line extending from the deltoid 
 tuberosity to the head of the humerus, and to the ole- 
 cranon. Action : Extensor of the fore-arm. 
 
 4. Middle extensor of the fore-arm. — Synonyms. 
 Humero-olecranius internus, (G). Caput parvum, (P). 
 
28 EQUINE ANATOMY. 
 
 Attachments : Internal face of the humerus, summit of 
 the olecranon, and a little below. Action : Extensor 
 of the fore-arm. 
 
 5. Small extensok of the fore-aem. Synonyms. 
 Anconeus. Small olecrano-humeralis, (G). Attach- 
 ments : Margin of the olecranon fossa, anterior and 
 external part of the olecranon. Action : Extensor of 
 the fore-arm. 
 
 Antibrachial Region,— Division. Anterior and pos- 
 terior. 
 
 Anterior region, four muscles. 
 
 1. Anterior extensor of the metacarpus. — Syno- 
 nyms. Epicondylo-premetacarpeus, (G). Extensor 
 metacarpi magnus, (P). Humero-metacarpeus, (L). 
 Attachments : Crest limiting downwards the groove of 
 torsion of the humerus, above and in front of the infe- 
 rior articular surface of the humerus, supero-anterior 
 tuberosity of the principal metacarpal bone. Action : 
 Extensor of the metacarpus. 
 
 2. Oblique extensor of the metacarpus. — Syno- 
 nyms. Cubito or radio-premetacarpeus, (G). Extensor 
 metacarpii obliquus vel parvus, (P). Kadio-metacar- 
 peus, (L). Attachments : External side of the radius, 
 head of the internal small metacarpal. Action : Exten- 
 sor and rotator of the metacarpus. 
 
 3. Anterior extensor of the phalanges. — Syilo- 
 
EXTREMITIES. 29 
 
 nyras. Epicondjlo-prephalangeus, (G). Extensor pedis, 
 (P). Humero-prephalangens, (L). Attachments : Be- 
 low the crest limiting the groove of torsion of the 
 humerus behind, in front of the inferior tuberosity of 
 that bone, external ligament of the elbow joint, supero- 
 external tuberosity of the radius, external border of 
 the same bone, pyramidal eminence of the os pedis. 
 Action : Extends the third phalanx upon the second, 
 this upon the first, and that upon the metacarpal. 
 
 4. Lateral extensor of the phalanges. — Syno- 
 nyms. Cubito or radio-prephalangeus, (G). Extensor 
 suffraginis, (P). Attachments : External tuberosity of 
 the radius, external lateral ligament of the elbow joint, 
 on the body of botli bones of the fore-arm, capsular 
 ligament of the fetlock joint, and superior extremity of 
 the OS suffraginis. Action : Extensor of the digital 
 region proper. 
 
 Posterior region, five muscles. 
 
 1. External flexor of the metacarpus. — Syno- 
 nyms. Epicondylo-supercarpeus, (G). Flexor metacarpi 
 extern us 5 (P). Humero-supercarpeus externus, (L). 
 Attachments : Summit of epitrochlea, the trapezium 
 and the head of the external small metacarpal. Action : 
 Flexor of the metacapus. 
 
 2. Oblique flexor of the metacarpus. — Synonyms. 
 Epitrochlea supercarpeus, (G). Flexor metacarpi med- 
 
30 
 
 EQUINE ANATOMY. 
 
 ins, (P). Humero-metacarpeus interims, (L). Attach- 
 ments: Base of the epicondyle, olecranon and the trape- 
 siiim. Action : Flexor of the metacarpus. 
 
 3. Internal flexor of the metacarpus. — Synonyms. 
 Epitrochlea metacarpeus, (G). Flexor metacarpi inter- 
 nus, (F). Humero metacarpeus internus, (L). Attach- 
 ments : Base of the epicondyle, the head of the inter- 
 nal metacarpal. Action : Flexor of the metacarpus. 
 
 4. Superficial flexor of the phalanges. — Syno- 
 nyms. Epitrochlo-phalangeus, (G). Flexor pedis per- 
 foratns, (F). Humero coronaris or phalangeus, (L). 
 Attacliments : Summit of the epicondyle, the extremi- 
 ties of the pulley behind the superior extremity of the 
 OS coronge. Action : Flexes the second phalanx on the 
 first, this on the metacarpal, and the whole digital 
 region on the fore-arm. 
 
 5. Deep flexor of the phalanges. — Synonyms. 
 Cubito or radio-phalangeus, (G). Flexor pedis perfor- 
 atus, (P). Humero-radio-phalangeus, (L). Attach- 
 ments : Summit of the epicondyle, summit and pos- 
 terior border of the olecranon, posterior face of the 
 radius, plantar crest of the os pedis. Action : Flexes 
 the phalanges on each other and on the metacarpus, 
 and the wliole foot on the fore-arm. 
 
EXTREMITIES. 31 
 
 ANGEiOLOGY. 
 
 Arteries : the superior and inferior scapular with 
 the humeral. 
 
 Superior scapular, or superscapular — collateral 
 branch of the axillary artery — I'uns upwards between 
 the subscapularis muscle and the antea-spinatus, and 
 terminates at the lower part of the scapula. 
 
 Inferior scapular, or subscapular ^ also collateral 
 branch of the axillary, runs between the subscapularis 
 muscle and the adductor of the arm to the dorsal 
 angle of the scapula; it li'is collateral branches to tlie 
 latissimus dorsi muscle, one forming the posterior cir- 
 cumflex of the shoulder, and also anterior and posterior 
 muscular branches. 
 
 Humeral artery is tlie terminal branch of the axil- 
 lary. It runs down inside of tlie arm to the inferior 
 extremity of the humerus, where it terminates by the 
 anterior and posterior radial. Its collateral branches 
 are : 1 — the prehumeral or anterior circumflex of tlie 
 shoulder going to the mastoido-humeralis muscle ; 2 — 
 the external collateral of the elbow, or deep humeral, 
 passing to the large extensor of the fore-arm, and by 
 another branch to the front of the elbow joint ; 3 — the 
 internal collateral of the elbow, epicondyloid or cubital 
 artery, terminating at the carpus anastomosing with 
 
32 EQUINE ANATOMY. 
 
 the posterior radial artery ; 4 — the principal artery of 
 the coraco radialis, dipping into that muscle by ascend- 
 ing and descending branches. 
 
 Anterior radial artery passes in front of the 
 elbow joint, under the flexor muscles of the fore-arm 
 and of the anterior extensor metacarpi, to the anterior 
 face of the radius, to the knee, where it looses itself by 
 anastomosing with tlie posterior radial and the inter- 
 osseous of the fore-arm. 
 
 Posterior radial artery runs down under the in- 
 ternal ligament of the elbow joint, under the internal 
 flexor of the metacarpus, arrives at the inferior extrem- 
 ity of the radius, and terminates by the common trunk 
 of the interosseous metacarpal and the collateral of 
 the cannon. Its collateral brandies are : 1 — articular 
 branches ; 2 — muscular braiK^hes to tlie posterior anti- 
 brachial muscles ; 3 — interosseous of the fore-arm, 
 
 which runs through the radio cubital arch under the 
 
 I* 
 extensor suffraginis ; 4 — small muscular and musculo- 
 cutaneous branches ; 5 — branches to the posterior face 
 of the radius. 
 
 Common trunk of the interosseous metacarpal. — 
 Passing inwards and behind the carpus, it reaches the 
 head of the internal small metacarpus, bends outwards 
 under the superior extremity of the suspensory liga- 
 ment, and anastomoses witli a branch from the super- 
 
EXTREMITIES. * 33 
 
 iicial arch which unites tlie cubital artery with the 
 collateral of tlie cannon, forming then the sub-carpal 
 arch — tlie super-carpal arcli being formed by the anas- 
 tomosis of the collateral of the cannoji and the epicoiir/ 
 dyloid itself. Collateral branches : two posterior 
 interosseous-metacarpal or palmar, and two anterior or 
 dorsal. The posterior run on the inside of both small 
 metacarpal bones, anastomosing downwards with the 
 collateral of the cannon. The anterior runs on the 
 outside of both small metacarpal bones, and downwards 
 anastomoses also with branches of the collateral of the 
 cannon. 
 
 Collateral artery of the cannon. — Passes under 
 the carpal arch downward on the internal side of the 
 flexor tendons to the fetlock, and ends in the digital 
 artery. Collateral branches are : 1 — to the epicondy- 
 loid artery to form the supracarpal arch; 2 — synovial, 
 tendinous^ and cutaneous ramuscules : 3 — branch to 
 the posterior interosseous of the metacarpal. 
 
 Digital artery.— On each side of the fetlock joint 
 it runs down to the basilar process and terminates in the 
 ungueal plantar and preplantar arteries. Collateral 
 branches : 1 — articular to the fetlock ; 2 — branch to 
 the tissue of the ergot; 3 — the perpendicular artery 
 of Percivall, ramifying into anterior and posterior 
 branches ; 4 — the artery of the plantar cushion run- yj-- 
 
 -C^i^MjjC y2^.««.-<.--C£o^ 
 
34 EQUINE ANA'HJMY. 
 
 iiiug downwards to that apparatus ; 5 — tendinous and 
 cutaneous branches to the lirst and second phalanges ; 
 6 — the coronary circle or two branches, anterior and 
 posterior, running round the coronet and anastomos- 
 ing with those of tlie opposite side. 
 
 Ungueal preplaktar. — Passes through the notch of 
 the lateral extremity of the os pedis, goes to the 
 preplantar fissure, runs forwards, and ends by divisions 
 dipping into the os pedis. / ^ ^<n4^v.vw^ u^ U""^ 
 
 Ungueal plantar. — Lodged in the plantar fissure, 
 then in the plantar canal, and into the semi-lunar 
 sinus of the os pedis, it anastomoses wtt^h that of the 
 opposite side, forming tlie semi-lunar arch. Collateral 
 branches ascend to form the anterior laminal of 
 Spooner, and descend to form the inferior commu- 
 nicating arteries. 
 
 Veins. — Digital veins, wliicli form in tb.e foot a rich 
 network — satellite of the arteries of that region — 
 emptying into three metacarpal or collateral of the can- 
 non ; these are two 'superficial veins on each side of 
 the flexor tendons, and a third, deep, passing under 
 the suspensory ligament. Following these are two 
 groups of autibrachial veins, one formed by tlie cubital 
 and the posterior radial, which run alongside the arter- 
 ies of the same name; the other, the median vein, 
 which receives the superficial anterior radial. These 
 
EXTREMITIES. 35 
 
 antibracliial unite with the anterior radial, satellite of 
 the artery of the same name, and form the humeral 
 vein, which receives the subcutaneous thoracic and the 
 subscapular, to form the axillary which empties into 
 the confluent of the jugular. 
 
 LymphaticSi — Coming from all parts of the limb, 
 they pass to the prescapular and brachial glands, which 
 send out numerous efferent branches, terminating in 
 the prepectoral glands. 
 
 NEUROLOGY. 
 
 Brachial plexus. — Formed by the sixth, seventh 
 and eighth cervical, and two flrst dorsal p ^irs of rach- 
 idian nerves, it lies outside of the two portions of the 
 scalenus muscle, under the shoulder near the scapulo- 
 humeral angle, and divides iiito fourt^yp ^if'Blp^^^y^ 
 "7r~l. DiaphrIgmatic NERViPruns inside the thoracic 
 cavity, along the course of the axillary artery with 
 the pncumogastric, there it receives branches from 
 the sympathetic nerve, reaches the base of tlio heart, 
 runs under tlie pleura to the phrenic mrt of the dia- 
 phragm, wliere it ends.^"^ K^xJi^t^ -^ka-*«^^ 
 
 2. Nerve of the angularis and rhomhoideus mus- 
 cles, formed by the sixth cervical pair, runs upward 
 to these two muscles. 
 
 3. Nerve oFyTUK serratus magnus or ^super^r 
 
 y ^ ^ «■ ^^^^ ^,*«*, -H-r^ • ' 
 
 ^ ^^^.KO^ 
 
36 EQUINE ANATOMY. 
 
 thoracic, from the sixtli and seventh cervical pairs, runs 
 across the serratiis niagniisiiniscle aiKJ terminates in it. 
 
 4. ^ERVE OF THE PECTORAL MUSCLES or inferior 
 thoracic: five principal; one to the sterno prescapulafis 
 muscle, another passing between the two pectoral mus- 
 cles and ramifying in the superficial pectoral, the three 
 other branches going to tlie sterno trochineus muscle. 
 
 5. Subcutaneous thoracic neryj: rises in common 
 with the cubital nerve and runs backward on the in- 
 ternal face of the long extensor of the fore arm and 
 of the panniculus carnosus, as far as the flank, where 
 it terminates in the subcutaneous muscle of that 
 region. 
 
 6. ISeRVE of THE LATISSIMUS DORSI fomicd bv tllC 
 
 eighth cervical pair, runs upwaids and backwards to 
 that muscle, where it is distributed. 
 
 7. Axillary or circumflex nerve, from the eight 
 €crvical pair, runs backwards and downwards on the 
 internal face of the subscapularis muscle, passes be- 
 tween it and the teres major, crossing tlie subscapular 
 artery ; behind the scapulo-humeral joint, passes be- 
 tween the short abductor of the arm, the great and 
 middle extensor of tlie fore arm, reaches the long al)- 
 ductor of the arm and terminates in tlie two abductors, 
 the mastoido humeralis and tlie skin. 
 
 8. Nerve of the adductor of the arm, also from 
 
EXTREMITIES. 37 
 
 the eighth cervical pair to tlie ad(hictor muscle. 
 9. Nerve of the subscapularis Muscr.E. — Two 
 braiicly3s ramifying in that muscle, y^ ^-"^^^^^^^^^ 
 
 0/Sus-scAPULAR nerve. — Formed ])y the sixth 
 and "seventh cervical pairs, running backwards between 
 tlie angnlaris scapulae, tlie sterno prescapularis and 
 the antea spinatus muscles, reaches the posterior fossa 
 of the external face of the scapula, where it termi- 
 nates in the postea spinatus muscle. 
 
 11. Anterior brachial nerve or musculo-cutane- 
 ous. — Formed hy the seventh and eighth cervical pairs 
 — situated on the inside of the scapulo humeral joint, 
 crossing the axillary artery and passing underneath it, 
 united to the median nerve, runnino- in frpnt of it to 
 the bifurcation of the omo-brachialis muscle, passing 
 between its branches and (iippin^ into,-; the coraco- 
 radialis mnscle. = 'f^^^ ^x^^.^^'H^ 
 
 12. Radial nerve. — Tlie largest of the plexus — 
 formed principally by the iirst dorsal pair. It passes 
 downwards and backwards, under and across the sub- 
 scapularis and adductor nmscles parallel to the hume- 
 ral artery and posterior to the cubital nerve. At the 
 deep humeral artery it passes behind the humerus, un- 
 der and then alongside the short flexor of the fore- 
 arm to the anterior face of the elbow joint and the 
 radius ; then under the extensors of the metacarpus 
 
38 
 
 EQUINE ANATOMY. 
 
 and extensor of the phalanges, meets the radial art- 
 ery, with which it goes to the oblique extensor of the 
 metacarpus and terminates. Collateral branches are 
 to the tendons of the great dorsal and adductor of the 
 arm, to all tlie extensors of the fore-arm, the skin, 
 the anterior extensor and external flexor of the meta- 
 carpus and to the extensors of the phalanges. 
 
 13. CuBiTO-cuTANEous or cubital nerve — Formed by 
 tlie dorsal pairs. It rims backwards and downwards, 
 behind the humeral arteiy ; crossing the deep hftmeral 
 artery, it passes between the long and middle extensors 
 of ths fore arm, to the inside of the elbow, over the 
 epitrochlea, under the cubital fasciculus of the middle 
 flexor of the metacarpus, under this muscle to the 
 trapezium bone, where it ends by two branches : one, 
 cutaneous, passing between the tendons of the exter- 
 nal and middle flexors of the metacarpus and through 
 the antibrachial aponeurosis to ramify in the skin of 
 tliis region ; the other, with a branch of the median 
 nerve, forms the external plantar nerve. Collateral 
 branches, two : one to the skin of the fore-arm below 
 the elbow on the inside, the other to some muscles of 
 the posterior antibracliial region. 
 
 14. CUBITO-PLANTAR OR MEDIAN NERVE. Fomicd by 
 
 the eiglith cervical and the dorsal pairs. Starts from 
 the posterior part of the plexus to reacli the axillary 
 
EXTREMITIES. 39 
 
 artery, there anastomoses with tlie anterior brachial 
 nerve, phices itself in front of tlie 1 mineral artery, run- 
 ning with it to its terminal bifurcation, passes down- 
 wards on the inside of the leg with the posterior ra- 
 dial artery, arrives at the elbow joint, becomes poste- 
 rior, and a])ove the inferior third of the fore-arm bifur- 
 cates to form the plantar nerve. Collateral branches : 
 1. One branch to the thoracic nerve going to the super- 
 ficial pectoral muscles. 2. In the middle of the 
 humerus, one branch wdiich passes beneath the coraco- 
 brachialis and terminates in two small branches. 3. 
 In the antibrachial region, branches to the internal 
 flexor of the metacarpal and to the flexors of the pha- 
 langes. 
 
 Plantar nerve. — External and internal. Internal 
 lies beside the collateral artery of the cannon, alons^- 
 side the perforans tendon to near the fetlock, where 
 it terminates by several digital branches. Collat- 
 eral branches to the skin of the metacarpal region, 
 and one which crosses obliquely behind the flexor ten- 
 dons and unites with the external plantar nerve. Ex- 
 ternal plantar nerve is formed by a branch from the 
 cubital and one from tlie median nerve, runs in com 
 pany with the external collateral vein of the cannon 
 and an arteriole, outside of the flexor tendons at the 
 superior extremity of the cannon, inside of the head 
 
40 EQUINE ANATOMY. 
 
 of tlie external small metacarpal bone, gives off the 
 deep palmar branch, then passes along the tendon of 
 the perforans muscle, recQives the branch , of. the in- 
 ternal plantar and at the fetlock terminates m the 
 digital branches. 
 
 Digital branches, or collaterals of the digit — three 
 in number — one anterior, one middle and a posterior. 
 The anterior placed in front of the vein goes to the 
 skin of the anterior face of the digit. The middle, 
 between the artery and vein, goes to the coronary 
 cushion and the podophyllous tissue. The posterior, 
 behind the artery and larger than the other, lies first 
 above the artery and then behind it, runs down to the 
 basilar process, into the lateral fissure of the os pedis 
 and ramifies in the podophyllous tissue and the bone. 
 Collateral branches : 1 — to the flexor tendons ; 2 — to 
 the plantar cushion ; o — to the cartilages of the os 
 pedis; 4- — to the reticulum of the podophyllous tissue; 
 5 — a plantar branch. 
 
 COMPLEMENTAKY APPENDAGES AND TeGUMENTARY COV- 
 ERINGS OF THE DIGITAL REGION. — They coiisist of the 
 fibro cartilages of the os pedis, the plantar cusliion, 
 and of the keratogenous membrane — the whole cov- 
 ered by the horn)^ apparatus or hoof. 
 
 Fibro-Cartilages of the os pedis — situated one on 
 eacli side — offer an external fnce convex, an internal 
 
 i 
 
EXTREMITIES. 41 
 
 face concave, continue downwards and backwards to 
 the plantar cushion ; tlie superior border is thin and 
 flexible, the inferior thick and attached to the basilar 
 and retrossal processes; the posterior border is slightly 
 convex, the anterior is intimately united to the anterior 
 lateral ligament of the articulation of the foot. 
 Structure : is a mixture of fibrous and cartilaginous 
 tissue, liable to calcification. 
 
 Plantar Cushion. — Is a wedge placed between the 
 cartilages of the os pedis, between the perforans ten- 
 don and the inferior wall of the horny box. It has 
 an antero-superior face covered by a cell ulo- fibrous 
 membrane, and is moulded on the aponeurotic termina- 
 tion of the perforans tendon ; its inf ero-posterior face 
 is covered by the keratogenous membrane and offers 
 in its middle the pyramidal body representing the 
 shape of the frog of tlie foot. The base looks back- 
 wards and upwards ; it shows on each side the bulbs of 
 the plantar cushion, and is also covered by a cellulo- 
 fibrous covering. The apex is fixed on the plantar 
 face of the os pedis, in front of the semilunai- crest 
 and the insertion of the perforans tendon. The la- 
 teral borders are continuous with the internal face of 
 tlie lateral cartilages. Its structure consists of a 
 fibrous network mixed with elastic fibres, connective 
 fibres with adipose cells, blood vessels and nerves. 
 
42 EQUINE ANATOMY. 
 
 Keratogenous membrane, resting upon a fibrous 
 fascia and covered by the lioof. It is composed of the 
 coronary cushion, the velvety and laminal tissues. 
 
 Coronary tissue, bourrelet or cutidura. — It is 
 lodged in a cavity at the upper border of tlie horny 
 case. Its inferior border is separated from the 
 laminae bj a white zone ; the superior border is limited 
 by the perioplic ring; its extremities are reilexed near 
 the bulbs of the plantar cushion into tlie lateral lacu- 
 nae of the pyramidal body ; its surface is covered 
 with papillae, villi and villous loops ; its structure is 
 the same as the cutaneous derma, is very vascular 
 and has many nerves ; it is red, and sometimes macu- 
 lated black by pigment. 
 
 Yelvety tissue covers tlie plantar snrface of the 
 OS pedis and the plantar cusliion. Its surface is like 
 those upon whicli it rests, having a central and a periph- 
 eric portion covered by the sole. It is provided with 
 numerous villosities, received in the porosities of the 
 sole and frog, and has the same structure as the cuti- 
 dura, 
 
 Laminal or podophyllous tissue. — This covers the 
 anterior face of the os pedis. It consists of five or six 
 hundred laminai, parallel, wider below than above, den- 
 ticulated on their free border, and having folds on 
 their lateral surfaces ; they are received between the 
 
EXTREMITIES . 43 
 
 laminpe of the kerapliyllous tisue. Its structure is like 
 that of other parts of the keratogenous apparatus. 
 
 Hoof — is composed of tliree parts : wall, sole and 
 frog. 
 
 Wall, or crust. — Covers the anterior face of the 
 foot, diminishing in width and thickness posteriorly. 
 It passes round the bulbs of the plantar cushion, is in- 
 flected inwards and becomes confounded with the lat- 
 eral borders of the sole. It is divided into toe, outside 
 and inside toe, quarter, heels and bars. Its external 
 face is smooth and covered above by the periople, 
 which is a dependance of the frog. The internal face 
 presents tlie laminae of the kerapliyllous tissue. Its 
 superior border offers the cutigeral cavity with many 
 little holes for the villosities of the cutidura ; the in- 
 ferior is united to the sole, and the extremities form 
 the bars. 
 
 Sole — is a horny plate occupying the inferior face 
 of the hoof. The inferior face is more or less concave ; 
 the superior has numerous pores for the villi of the 
 velvety tissue ; the external border is united to the 
 wall : the internal forms a V shaped notch opening 
 backwards to receive tlie frog. 
 
 Frog — is a pyramidal mass of horn lodged between 
 the bars. Its inferior face has a median lacuna separ- 
 ating the branches ; the lateral faces are united to the 
 
44 EQUINE ANATOMY. 
 
 bars and internal border of the sole ; on each side 
 are found the lateral lacunae or commissures of the 
 frog ; the superior face rests on tlie pyramidal body of 
 the plantar cushion, has a triangular excavation divided 
 by the frog stay or sjmie of the frog ; its base forms 
 the glomes of the frog ; the apex rests on the point of 
 the angle formed by the posterior border of the sole. 
 
CHAPTER III. 
 
 POSTEEIOR OR ABDOMINAL EXTREMITIES. 
 
 OSTEOLOGY, 
 
 Hip. — OssA iNNOMiNATUM OR COXA, formed of three 
 pieces, iliiiin, pubis and ischium. 
 
 Ilium. — Division: Two faces, three borders, thiee 
 angles. The external face presents tlie iliac fossa ; 
 the internal face the iliac surface and an auricular facet 
 for articulation with the sacrum. The anterior border 
 is concave ; tlie external has a medullary foramen and 
 vascular grooves ; tlie internal forms the great sciatic 
 notch. The anterior external angle has four tuberos- 
 ities, the anterior internal only one ; the posterior 
 angle offers a facette for the cotyloid cavity, the supra- 
 cotyh)id crest, the ileo pectineal eminence, and some 
 muscular imprints. Development : two nuclei of ossi- 
 iication. 
 
 Pubis. — Division : Two faces, three borders, three 
 angles. The superior face is smooth and concave ; 
 the inferior has a large groove for the pubio- femoral 
 
46 EQUINE ANATOMY. 
 
 ligament. The anterior border is thin and rough; 
 the posterior thick and concave, and co-operates to 
 form the obturator foramen ; the internal is thick and 
 articular. The external or cotyloid angle forms the 
 bottom of the cotyloid cavity ; the internal and poste- 
 rior angles are articular. Development : one nucleus 
 of ossification. 
 
 Ischium. — Division : Two faces, four borders, four 
 angles. The superior face is smooth and forms the 
 floor of the pelvic cavity ; the inferior is roughened for 
 muscular attachments, and presents the ischial crest. 
 The anterior border forms the obturator foramen, the 
 external the small sciatic notch, the posterior forms 
 the ischial arch, while the internal is articular. The 
 anterior external angle, or cotyloid presents a diarthro- 
 dial facet and the posterior extremity of the supra- 
 cotyloid crest ; the anterior internal angle is articulated 
 with the pubis ; the posterior external forms the ischial 
 tuberosity and the posterior internal articulates with 
 that of the opposite side. Development : two nuclei 
 of ossification. 
 
 Thi^h. — Fp:muk. — Division: Bodv, and two Extrem- 
 ities. Body lias four faces. The ant^ouTYis smooth; the 
 posterior has a rounded, roughenec^surface, a slight 
 crest oblique above, in the middle a wide rough surface 
 for muscular attixhments, and below a wide vascular 
 
(r< 
 
 (t 
 
 V^ 
 
 groove; tlie external face shows tlie siibtrocliiinterian 
 crest and belo^y<-^:he suscondjloid fossa ; the internal 
 face shows the small troclianter, the medullary fora- 
 men surrounded by muscular imprints, the origin of 
 the vascular groove of the posterior face and the sus- 
 condyloid crest. Extremities : The superior lias an 
 articular head and neck, a great trochanter with apex, 
 convexity, and crest, and posteriorly the trochante- 
 rian fossa; the inferior has a wide trochlea, with inter- 
 nal border the highest, two condyles separated by 
 intercond^doid notch, two foss?e on the outside of ex- 
 ternal condyle, a rough , impression on the .inside of 
 the internal condyle, and a large tubercle outwards; 
 between the external condyle and trochlea a digital im- 
 pression for muscular attachments. Development : 
 four nuclei of ossification. 
 
 Le^.— Tibia. — Division : Body and two extremities. 
 Body has three faces and three borders. The external 
 face is smooth and concave ; the hiternal slightly con- 
 vex and with muscular imprints above ; the posterior 
 offers two trian2;ular surfaces with rouirh muscular 
 lines, and on their limits the medullary foramen. The 
 anterior border forms the tibial crest; the external, the 
 til)ial arch ; the internal is thick and rounded. Ex- 
 tremities : the superior has three tuberosities; the ante- 
 rior or the tibial tuberosity has a depressed centre ; the 
 
48 EQUINE ANATOMY. 
 
 external is articular and has a facet on the outside for 
 articulation with the fibula — it is separated from the 
 anterior by a groove ; the internal tuberosity is also 
 articular and has posteriorly a small tubercle for liga- 
 mentous attachment. On the middle of the superior 
 extremity is the tibial spine. The inferior extremity 
 lias a double articular pulley, outwards a tuberosity 
 with a vertical groove, and inwards another tuberosity 
 wdth an oblique groove posteriorly. Development : 
 four nuclei of ossification. 
 
 Fibula. — Division: Middle part and two extremities. 
 Middle part forms the tibial arch. Extremities : the 
 superior, or head, is wide and has inwards a facet for 
 articulation, outwards it shows muscular imprints ; the 
 inferior ends in a blunt point. Development : one 
 nucleus of ossification. 
 
 Patella. — Division : Three faces and a circumfer- 
 ence. The anterior face is convex and irregular ; the 
 superior roughened for muscular attachments ; the 
 posterior is moulded on the" femoral trochlea. The 
 circumference unites with the three faces. Develop- 
 ment : one nucleus of ossification. 
 
 Digital Region.— Tarsus. — Division: Six or seven 
 bones arranged in two rows. The superior row has 
 the astragalus with its six faces ; the superior, anterior, 
 inferior and posterior are articular ; the external and 
 
EXTREMITIES. 49 
 
 internal fiirnislied with ligamentous imprints. The os 
 calcis has an external face flat and smooth, an internal 
 face forming the tarsal arc.h, an anterior horder con- 
 cave, a posterior l)order thick and rough, a superior 
 extremity divided in three parts : one middle, for mus- 
 cular attachment ; one anterior, smooth, and one pos- 
 terior for the sliding of a tendon ; an inferior ex- 
 tremity, articular — it is developed by t\vo nuclei of os- 
 sification and the astragalus by onfe"<tTi^y. The inferior 
 row has four bones ;,\the cul^oid with six faces ; the 
 scaphoid, flat bone, with two faces and a circumfer- 
 ence ; the great cuneiform with two articular faces and 
 three borders ; the small cuneiform sometimes divi- 
 ded in two pieces, with four facet tes for articula- 
 lation. Development : all the bones of the inferior 
 row are dev^eloped by one nucleus of ossification . 
 
 Metatarsi. — Similar to the metacarpi. 
 
 Principal Metatarsus is longer, more cylindrical 
 than the metacarpus, and has on the outside border an 
 oblique Assure. Its superior articular surface is hol- 
 lowed by a fossa of insertion. 
 
 Rudimentary Metatarsi. — The external is always 
 the longest and the tliickest ; the internal has three 
 articular facets on the superior extremity. 
 
 Phalanges. — Almost exactly like those of the an- 
 terior extremity. 
 
50 EQUINE ANATOMY. 
 
 ^ SYi\DESWOLOGl. 
 
 Coxo-FEMORAL JOINT — Eiiartlirosis. On the ossa iii- 
 noniinatum the cotjloid cavity, on the femnr the artic- 
 nhir head, both united by the capsular, pubio and 
 coxo-femoral ligaments. One synovial capsula. All 
 motions. 
 
 Femoro-tibial joint — Imperfect hinge. On the 
 femur, the articular surface of the trochlea and tlie 
 two condyles ; on the tibia the two large f acettes at 
 the base of the tibial spine ; on the patella, its poste- 
 rior face enlarged by fibro-cartilaginous pad. Two in- 
 ter-articular menisci : the internal attached in front 
 and behind tlie tibial spine, the external fixed forward 
 near the internal meniscus, and behind by two branches, 
 one on the femur, the other on the tibia. Tliis joint 
 has three anterior patellar ligaments, two lateral, 
 two interosseous, one anterior capsular, with lateral 
 re-enforcing bands, and one posterior capsular liga- 
 ment ; three synovial capsulse. Motions : flexion, ex- 
 tension and rotation. 
 
 TiBio-FiBULAR JOINT — Artlu'odia. Irregular diar- 
 throdial facette on both bones. Interosseous and 
 peripheric ligamentous fibres, two small ligamentous 
 fasciculi and an aponeurotic membrane ; bolow a liga- 
 mentous cord. Motions very limited. 
 
EXTREMITIES. 51 
 
 7 
 
 Tarsal joint. — Division : , -Tibio-tarsal, superior 
 iiiter-tarsal, tarso-tarsal, inferior inter-tarsal, tarso-met- 
 atar^a\ ^^'^^ ^xi^'^^^ '^^'^ • 
 
 Tibio-tarsal joint — Perfect liinge. On the tibia 
 a donble pulley, on the astragalus, the trochlea of the 
 supero-anterior faces ; two lateral external, three lat- 
 eral internal, one anterior and one posterior ligaments ; 
 the last two are capsular. One synovial membrane. 
 Motions : extension and flexion. 
 
 Superior intertarsal joint — Arthrodia. Anterior 
 face of lower extremity of the os calcis and the poste- 
 rior facettes of the astragalus. Four ligaments : one 
 superior, one interosseous, one external and one inter- 
 nal. Sliding motion. 
 
 Tarso tarsal joint — Arthrodia. The facettes on the 
 OS calcis and the inferior face of the astragalus above, 
 below tlie superior face pf the scaphoid and cuboid, 
 bix ligaments : two lateral,rone calcaneo-nietatarsal, 
 one astragaio-metatarsal, one posterior tarso-metatarsal 
 and one interosseous. One synovial capsula. Motion 
 very limited. 
 
 Inferior inter-tarsal joint — Arthrodia — with al- 
 most no motion. On the cuboid two facettes for the 
 scaphoid and two for the great cuneiform ; on the sca- 
 phoid, facettes on the inferior surface for both cunei- 
 forms ; the two cuneiforms have each one small facet. 
 
52 EQUINE ANATOMY. 
 
 Two anterior and two interosseous- ligaments, with tlie 
 astj'agalo-metatarsal and posterior tarso-metatarsal liga- 
 ments are the means of nnion. 
 
 Tarso-metatarsal joint — Artlirodia.' The infer- 
 ior face of the cuboid and tlie two cuneiforms, with 
 the three metatarsi bones articulate by facettes. As 
 means of union it offers the ligaments of the tibio-tar- 
 €al joint, the calcaneo-metatarsal ligament, and the as- 
 tragalo-metatarsal and tarso-metatarsal ligaments. One 
 synovial capsula. The motions are nearlj" null. 
 
 3IY0L0G1. 
 
 Gluteal Rei?ioii, or Region of the Hip,— Three mus- 
 cles. 
 
 1. Superficial gluteus. — Synonyms, llio-trochan- 
 terius medius, (G). Gluteus externus, (P). Ilio-tro- 
 <ihanterius externus, (L). iVttachments : The internal 
 face of the gluteal aponeurosis, the posterior extremity 
 of the ischium, the ischiatic ligament, the external 
 tuberosity of the body of the femur. Action : Al)- 
 ductor of the thigh. 
 
 2. Middle gluteus. — Synonyms. Ilio-trochanterius 
 magnus, (G). Gluteus magnus, (P). Superior portion 
 of the great ilio-trochanterius, (L). Attachments : 
 The internal face of the gluteal aponeurosis, the super- 
 ior face and anterior angle of the ilium, the two ilio- 
 
EXTREMITIES. 53 
 
 «acral ligaments, the sacro-sciatic ligament, and on the 
 trochanter of the superior extremity of the femur by 
 three branches. Action : Extensor and abductor of 
 the thityh and assists in rearino^. 
 
 3. Deep gluteus. — Synonyms. Small ilio-trochan- 
 teriuSj (G). Gluteus parvus, (P). Attachments : The 
 neck of the ilium, the supra cotyloid crest, the inside 
 of the convexity of the great trochanter. Action : 
 Abductor of the thigh, and rotator inward indirectly. 
 
 Crural Region, or Region of the Thigh.— Division : 
 Anterior, posterior and internal. 
 
 Anterior Crural Region. — Three muscles. 
 
 1. Muscle of the fascia lata. — Synonyms. Ilio- 
 tiponeuroticus, (G). Tensor vaginae, (P). Ischio ro- 
 tuleus extermis, (L). Attachments : External angle of 
 the ilium, external crest of the femur, and to the 
 patella. Action : Flexor of the femur. 
 
 2. Crural triceps. — Division : Anterior straiglit, 
 vastus externus, vastus internus. 
 
 a. Anterior straight. — Synonyms. Ilio-rotuleus, 
 {G). Rectus, (P). Anterior ilio-rotuleus, (L). At- 
 tachments: By two tendous to the rim of the cotyloid 
 cavity, and to the anterior face of the patella. Action ; 
 Extensor of the leg and flexor of the thigh. 
 
 Ij. Vastus externus. — Attachments : External face 
 and external half of the anterior face of the femur, 
 
54 EQUINE ANATOMY. 
 
 superior face and external border of the patella. 
 Action : Extensor of the leg:. 
 
 c. Vastus internus. — Attachments : Internal face 
 and internal half of the anterior face of the femur, 
 superior face and internal border of the patella. Ac- 
 tion : Extensor of the leg. 
 
 - 3. Anterior grele. — Synonyms. Ilio-femoral grele. 
 (G). Crureus vel cruralis, (P). Attachments : Rim 
 of the ilium, superior part of the anterior face of the 
 femur. Action : Raises the capsular ligament of the 
 coxo-femoral joint. 
 
 Posterior trural Region,— Three muscles. 
 
 1. Long vastus. — Synonyms. Ischio-tibialis exter- 
 nus, (G). Biceps abductor femoris, (P). Anterior 
 pubio-ischio-tibialis, (L). Attachments : The anterior 
 portion to the sacral spine, sacro-sciatic ligament, 
 coccygeal aponeurosis, ischial tuberosity, behind the 
 sub-trochanterian crest and to the anterior face of the 
 patella ; the posterior portion to tlie iscliial and the 
 tibial crests. Action : Abductor of the leg and ex- 
 tensor of the tliigh ; also flexes the leg, and is a tensor 
 of the tibial aponeurosis. 
 
 2. Semi-tendinosus. — Synonyms. Ischio-tibialis me- 
 dius or posticus, (G). Adductor tibialis, (P). Pos- 
 terior sacro-ischio-tibialis, (L). Attachments : Sacral 
 spine, sacro-ischiatic ligament, the ischial tuberosity, 
 
EXTREMITIES. 55 
 
 and anterior crest of the tibia. Action : Flexor of the 
 leg and tensor of the tibial aponeurosis ; it also assists 
 
 in rearing. a^:^cCit^^,-±:::::^:^^:f^ , 
 
 3. Semi-membranosus. — Synonyms. Ischio-tibialis 
 
 internus, (G). Adductor tibialis, (F). Great ischio- 
 femoralis, (L). Attachments : to the coccygeal apon- 
 eurosis, the ischial tuberosity, inferior face of the 
 ischium and ©sternal condyle of the femur. Action : 
 Adductor of the limb, extensor of the thigh, and 
 assistant in rearing. 
 Internal Crural Region. — Mne muscles. 
 
 1. Long adductor of the leg. — Synonyms. Sub- 
 lumbo-tibialis, (G). Sartorius, (P). Internal ilio-rotu- 
 leus, (L). Attachments: To the iliac fascia, near the 
 tendon of the small psoas muscle, and to the internal 
 patellar ligament. Action : Adductor of the leg and 
 flexor of the thigh. 
 
 2. Short adductor of the leg. — Synonyms. Sub- 
 pubio-tibialis, (G). Gracilis, (P). Pubio-tibialis, (L). 
 Attachments : Ischio-pubic symphysis, internal patellar 
 ligament, and the internal face of the tibia. Action : 
 Adductor of the leg and tensor of the tibial aponeu- 
 rosis. 
 
 3. Pectineus . — Synonyms. Superpubio-femoralis, 
 (G). Anterior pubio-femoralis, (L). Attachments : 
 On the inferior face of the pubis, and around the med- 
 
56 EQUINE ANATOMY. 
 
 ullary foramen of tlie femur. Action : Adductor and 
 flexor of the tliigh and rotator inwards. 
 
 4. Small adductor of the thigh. — Synonyms. Ad- 
 diictor brevis, (P). Middle pnbio-femoralis, (L)» 
 Attachments : To the inferior face of the pubis, and the 
 posterior face of the femur. Action ; Adductor of the 
 thigh. 
 
 5. Great adductor of the thigh. — Synonyms.. 
 Adductor longus , (P). Posterior pubio-femoralis, (L). 
 Attacliments : On the inferior face of the ischium, the 
 posterior face and above the internal condyle of the 
 femur. Action : Adductor, extensor and rotator out- 
 wards of the fenuir. 
 
 6. Square Crural. — Synonyms. Ischio-femoral 
 grele, (G). Not described by P. Small ischio-femor- 
 alis, (L). Attachments : In front of the ischial tuber- 
 osity and on the posterior face of the femur. Action : 
 Extensor and adductor of the femur. 
 
 7. External obturator. — Synonyms. Subpubio- 
 trochanterius externus, (G). Attaclnnents : On tlie 
 inferior face of the pubis and ischium and in the tro- 
 chanterian fossa. Action : Adductor and rotator out- 
 wards of the femur. 
 
 8. Internal obturator. — Synonyms. Subpubio- 
 trochanterius internus, (G). Attachments : On the an- 
 terior angle of tlie sacrum, the superior face of tlie 
 
EXTREMITIES. 
 
 57 
 
 •pubis, around the obturator foramen, and in the tro- 
 chanterian fossa. Action : Kotator outward of the 
 thigh, and possibly abductor. 
 
 9. Gemelli of the pelvis. — Synonyms. Ischio- 
 trochanterius, (G). Gemini, (P). Bifemoro-calcaneus, 
 (L). Attachments : On the external border of the isch- 
 ium and in the trochanterian fossa. Action : Rotator 
 outwards of the thigh. 
 
 Tibial Region, or Region of the Leg.— Division : 
 Anterior and posterior. 
 
 Anterior region. — Three muscles. 
 
 1. Anterior extensor of the phalanges. — Syn- 
 onyms. Femoro-prephalangeus, (G). Extensor pedis, 
 (P). Attachments : In the digital fossa, situated be- 
 tween the external condyle and the external border of 
 the trochlea of tlie femur, to the capsular ligament of 
 the fetlock joint, the anterior face of the two first 
 phalanges and the pyramidal eminence of the os pedis. 
 Action : Extends the digits and flexes the whole digital 
 region. 
 
 2. Lateral extensor of the phalanges.— Synonyms, 
 Peroneo-prephalangeus, (G). Peroneus, (P). Tibio- 
 prephalangeus, (L). Attachments : On the external 
 femoro-tibial ligament, the fibula and to the tendon of 
 the anterior extensor. Action : Same as the extensor 
 pedis. 
 
58 EQUINE ANATOMY. <OL ^ >. 
 
 3. Flexor of the metatarsus. — Synonyms. Tibio-* 
 premetatarsiis, (G). Flexor metatarsi^ (P). Attach- 
 ments : In the fossa of the inferior extremity of the 
 femur with the anterior extensor pedis, the external 
 fossa of the tibia, on the anterior tuberosity of the 
 superior extremity of the principal metatarsal by two 
 tendons, to the anterior face of the cuboid and to the 
 small cuneiform. Action : Flexor of the foot on the 
 leg. 
 
 Posterior region. — Six muscles. 
 
 1. Gemelli of the leg or gastrocnemii. — Syno- 
 nyms. Bifemoro-calcaneus, (G). Gastrocnemius ex- 
 ternus, (P). Attachments : By two fleshy bodies on 
 the rough edge of the sus-condyloid fossa, on the in- 
 side .of the f emui'^nd on ^4^ ^P^^ <^ the os calcis. 
 Action : Extensor of the foot on the tibia. J ^^ "- 
 
 2. SoLEus OR SoLEARis. — Syuonyms. Peroneo-cal- 
 caneus, (G). Plantaris, (P). Attachments: Supero- 
 external tuberosity of the tibia and the tendon .of the 
 gastrocnemii. Action : Like the gemelli of the leg. 
 
 3. Superficial flexor of the phalanges.— Synon- 
 ym. Femoro-phalangeus, (G). Gastrocnemius intern- 
 nus, (P). Attachments: Sus-condyloid fossa and the 
 coronet. Action : Flexes the second phalanx on tlie-. 
 flrst and tliat on the metatarsus. 
 
 4. PoPLiTEUs. — Synonyms. Femoro-tibialis obliq- 
 
EXTKEMITIZS. 59 
 
 uiis, (G). Attachments : On the external condyle of 
 the femur, the superior triangular surface of the pos- 
 terior face of the tibia. Action : Flexor of the leg 
 and rotator inwards. 
 
 5. Deep flexor of the phalanges. — Sjnnnyms. 
 Tibio-phalangeus, (G). Flexor pedis, (P). Great 
 tibio-phalangeus, (L). Attachments : The posterior 
 face of the tibia on its lower triangular surface, the 
 supero-external tuberosity of the same bone, to the 
 fibula, the interosseous ligament of the tibio -fibular 
 joint, and the semilunar crest of the os pedis. Action: 
 Flexes the phalanges on each other and on the meta- 
 tarsus, and extends the whole digital region on the 
 tibia. 
 
 6. Oblique flexor of the phalanges. — Synonyms. 
 Peroneo-phalangeus, (G). Flexor pedis accessorius, 
 (F). Small tibio-phalangeus, (L). Attachments : To 
 the external tuberosity of the superior extremity of 
 the tibia and the tendon of the flexor perf orans. 
 Action: Congener of the deep flexor. 
 
 )f the deep fle:j 
 ANGEIOLOGY. 
 
 Arteries. — F^oral^ prplonffatjon of the external 
 
 J iliac imd^r^he^^^jgi crest between the pectineus, the 
 
 •«a^Oi4«s and th"e p^as iliacus, runs along the pectineus 
 
 and the vastus internus, passes between the two branches 
 
 *i3> 
 
 \i '^: 
 
60 EQUINE ANATOMY. 
 
 of the great adductor of the thigh, through the pos- 
 terior vascular groove of the femur, and to the superior 
 extremity of the bifemoro-calcaneus muscle where it 
 becomes popliteal. Its collateral branches are : 1 — The 
 prepubic, rising with the deep musculara-unnin^ through 
 the crural ring on the anterior face of^thecrural arch, 
 ^ l^ hohmd the nock 9f thq vagintuchoat ri, and terminates in 
 the posterior abdominal and the external pujtic arteries. 
 ' The posterior abdominal runs forward between the 
 small oblique and traiisverse muscles, of tlie abdomen, 
 along the external border of the rectus abdominis, 
 w^here it ends by anastomosis with the anterior abdom- 
 
 inal;'^ The external piAic descends on the posterior 
 wall of the in o:uinal canal, at the inferior rinoj of which 
 it ends in the', sub-cutaneous abdominal and the anterior 
 dorsal of the penis ; the sub-cutaneous abdominal 
 anastomoses with its congener at the umbilicus; the 
 anterior dorsal of the penis passes to the superior bor- 
 der of the penis and ends in ascending branches to 
 the cavernous artery, and descending branches to the 
 erectile tissue at the extremity of the organ. In the 
 female, the dorsal of the penis becomes the mam- 
 mary, distributed to the mammae. 2 — Deep mus- 
 cular, or profunda, runs backward between the psoas- 
 iliacus and pectineus muscles, then between the pec 
 tineus and the external obturator, under the adductor 
 
EXTREMITIES. 61 
 
 of the tbio-b, behind the feraui*, and disappears in tlie 
 crural mnscles. 3 — The superficial muscular, or great 
 anterior muscular, runs downwards, outwards and for- 
 wards, passing between the sartorius, psoas-magnus and 
 iliacug muscles, then between the vastus internus and 
 the straight anterior muscles, and terminates in the 
 triceps cruralis. 4 — A number of innominated branch- 
 es, or small muscular, amongst them the nutritive of 
 the femur. 5 — The saphena runs between the two 
 adductors of the leg to the internal face of the limb, 
 or to the surface of the gracilis, where it terminates 
 in two small branches. 
 
 Popliteal. — Continuation of the femoral ; it di- 
 rects its course downwards between the bodies of the 
 bifemoro calcaneus, under the popliteus muscle and at 
 the tibial arch terminates in the posterior and anterior 
 tibial. Collateral branches : 1 — femoro-popliteal, with 
 its ascending and descending terminal ramifications ; 
 2 — articular branches ; 3 — muscular branches. 
 
 Posterior tibial. — Situated under the popliteus, 
 the oblique and deep flexors of the phalanges, it runs 
 down to the hock joint and becomes more and more 
 superficial ; near the os calcis it runs through the tibial 
 aponeurosis, passes into the tibial arch and at the as- 
 tragalus ends in the plantar arteries. Collateral 
 branches : 1 — musculo-tibial branches ; 2 — the medul- 
 
62 EQUINE ANATOMY. 
 
 lary artery of the tibia; 3 — tarsal articular branches; 
 4 — cutaneous brandies. 
 
 Plantar. — One each side of the perforans tendon, 
 thej run down in the tarsal arch to the suspensory 
 ligament and anastomose with the perforating pedal 
 artery. Collateral branches : 1 — tarsal articular ; 2 — 
 superficial arteries to the tendons ; 3 — deep external 
 and internal interosseous plantar arteries. 
 
 Anterior tibial. — Runs through the tibial arcli on 
 the anterior face of the tibia, under the flexor metatarsi, 
 and at the tibio-tarsal joint becomes the pedal, after 
 sendins: off collateral muscular branches. 
 
 Pedal. — Passes in front of the hock joint, bending 
 outwards, and on a level with the lower row of bones, 
 divides into perforating pedal and metatarso-pedal 
 arteries. 
 
 Perforating pedal. — Runs through the hock joint 
 and anastomoses posteriorly with the plantar artery of 
 the posterior tibial. 
 
 Metatarso-pedal. — Passes in the fissure outside of 
 the large metatarsal bone, forward of the external 
 rudimentary one, then to the posterior face of the first 
 named bone above the sesamoid groove, and terminates 
 in the collaterals of the digit or the digital arteries. 
 Collateral branches are tendinous, ligamentous, cutane- 
 ous and articular. 
 
EXTKEMlTiES. 63 
 
 Digital. — (See the anterior extremity, page 33). 
 
 Veios* — Tiie subuno^ueal network from wliicli rises 
 tlie two digital veins. To these succeed three meta- 
 tarsal veins, common origin of all the veins of the leg. 
 These are divided into superficial and deep ; two su- 
 j)erficial — the saphena, and two deep — the tibial. All 
 empty in the popliteal, which is continued by the 
 femoral, and this by the external iliac, which re- 
 ceives only one important vein, viz. — the circumflex 
 iliac. The external iliac vein uniting with the internal 
 iliac form the primitive iliac or pelvi-crural trunk, 
 which empties into the posterior vena cava. 
 
 Lymphatics. — They all converge towards the sub- 
 lumbar ganglions and present in their extent other 
 ganglionary masses constituting the deep and super- 
 ficial ingunial, popliteal, iliac, and precrural ganglions, 
 to each of which afferent lymphatic vessels arrive, and 
 from which efferent vessels are given off. 
 
 NEUROLOGY. 
 
 Lumbar Plexus.— Formed by the two last lumbar 
 and three first sacral pairs of nerves, is divided into 
 anterior and posterior portions. The first is concealed 
 by the small psoas muscle, and lies in front of the 
 internal iliac artery. The posterior, on a level with 
 the great sciatic notch, is in connection inwards with 
 
64 
 
 EQUINE ANATOMY, 
 
 psoas mns- 
 
 Vi 
 
 tlie subsacral blood vessels, outwards and in front with 
 the gluteal vessels. The anterior portion ends in the 
 <irural and obturator nerves, and gives off the iliaco- 
 muscular. The posterior is continued by the great 
 sciatic and external popliteal-sciatic nerves, after giving 
 ■off the small sciatic including the anterior and posterior 
 
 ^■^^frftiAtJO-mjscuLAR. — Ramifying in the ps 
 -cles. 
 
 2. Crural or anterior femoral. — Descends be- 
 tween the small and the great psoas to terminate in 
 the triceps cruralis muscle. Collateral branches : Ac- 
 cessory of the internal saphena and the internal saphena, 
 both becoming sub-cutaneous before terminating. 
 
 3. Obturator. — Runs alongside the obturator artery 
 under the internal obturator muscle throuo^h the obtu- 
 rator foramen, and ramifies in the deep muscles of 
 
 w^l the internal crural region. 
 
 4. Small sciatic or anterior and posterior glu- 
 teal. — Anterior gluteal or ilio-rauscular : Four or 
 five branches from the two first sacral pairs, going to 
 the middle gluteus muscle. Posterior gluteal or ischio- 
 muscular : Two in number ; one, superior, goes to the 
 long vastus ; and one, inferior, passes under that muscle, 
 and the semitendinosus towards the ischial tuberosity, 
 where it ends in cutaneous branches. 
 
extremities. 65 
 
 5, Great sciatic, or great femoro-popliteal. — 
 Passes tlirouo^h tlie 2:reat sciatic notch outside the isclii- 
 atic ligament, over the small glutens, behind the 
 gemelli of the pelvis and the square crural, bends 
 downwards behind the femur in front of the ischio- 
 tibial muscles, passes between the bellies of the 
 bifemoro-calcaneus, behind the perforatus, reaches the 
 hock, and at the os calcis divides into the external and 
 internal plantar nerves. Collateral branches : 1 — The 
 external sciatic-popliteal, or small femoro-popliteal, 
 runs forwards and downwards between the long vastus 
 and the gastrocnemius externus, and on the outside 
 of the superior extremity of the leg terminates in the 
 musculo-cutaneous and anterior tibial branches. The 
 musculo-cutaneous passes under the tibial aponeurosis 
 between the anterior and lateral extensors of the pha- 
 langes, becoming subcutaneous to terminate. The 
 anterior tibial runs under the anterior extensor pedis 
 to the front of the hock, with the pedal artery down 
 to the fetlock, where it ends by cutaneous filaments. 
 2 — Branches to the deep muscles of the internal crural 
 region. Leaving the sciatic at the middle of the supra- 
 cutyloid crest, these branches pass behind the coxo- 
 femoral joint and branch off to the muscles. 3 — 
 Branches to the posterior crural muscles, rising from 
 the sciatic at the gemelli muscles, and then te.'minating 
 
 \ 
 
66 EQUINE ANATOMY, 
 
 by several ramifications. 4 — The external saphena 
 passes over the external body of the bifemoro-calca- 
 neoiis, downwards to the origin of the tendo-Achillis, 
 on the outside of which it passes over to the tarsus 
 and terminates in the metatarsus. 5 — Branches to 
 the posterior tibial muscles, several in number, coming 
 from the sciatic as it passes between the gemelli of 
 the leg, and then ramifying in these muscles. 6 — Cuta- 
 neous branch as it runs along the tendo-Achillis. 
 
 Jt^LANTAR. — Situated in the tarsal sheath, behind the 
 perforans tendon, they reach the upper extremity of 
 the metatarsus, and separating from each other run on 
 each side of the tendons of the deep fl.exors to the 
 fetlock joint, and terminate as those of the anterior 
 extremity. 
 
CHAPTER lY. 
 
 HLE^D. 
 
 OSTEOLOGY. 
 
 The HEAD is divided into cranium and face. 
 
 Cranium. — Division : Seven bones — occipital, pari- 
 etal, frontal, ethmoid, sphenoid and two temporals. 
 
 Occipital. — Division : Two faces and a circum- 
 ference. External face is divided into three parts. 
 Presents parietal crest, occipital protuberance, cervical 
 tuberosity, occipital foramen, basilar process, mastoid 
 crest, muscular imprints, condyles, styloid process, notch, 
 condyloid fossa and foramen. Internal face, concave, 
 forming the posterior cavity of the cranium. Cb*cum- 
 ference is divided into two anterior and two posterior 
 lateral borders, joined by four angles. Development; 
 four nuclei of ossification. 
 
 Parietal. — Division : Two faces and four borders. 
 External face is convex, and shows the parietal crest 
 
68 EQUINE ANATOMY. 
 
 Internal face has digital marks, and the internal parietal 
 protuberance. The borders are dirided into superior, 
 inferior and lateral, and are articular. Development : 
 three nuclei of ossification. 
 
 Fkontal. — Division : Two faces and four borders. 
 External face divided into three parts, shows the 
 orbital process, the supra-orbital foramen, and a cavity 
 for the internal oblique muscle of the eye. Internal 
 face is also divided into two parts, superiorly has a 
 median crest and a notch for the sphenoid ; inferiorly 
 it opens in the frontal sinuses. Borders : the superior 
 articulates with the parietal, the inferior with the nasal 
 and lachrymal, the lateral has a superior notch for the 
 sphenoid, and one inferior for the orbital foramen. 
 Development : two nuclei of ossification. 
 
 Ethmoid. — Division : Perpendicular lamina and 
 two lateral masses. Perpendicular lamina : Two 
 faces, flat ; four borders : the superior forms the crista- 
 galli process ; the inferior, continuous with the septum 
 nasi ; the anterior, with the septum of the frontal 
 sinuses ; the posterior, with that of the sphenoidal 
 sinuses. Lateral masses. — Division : Middle part, base 
 and apex. The external surface of the first is divided 
 into external and internal portions; the internal sur- 
 face forms the cavities of the volutes. Tlie base has 
 the cribriform plate and the ethmoidal fossa. The 
 
HEAD. 69 
 
 apex forms the inferior extremity of the cells. Devel- 
 opment: three nuclei of ossification. 
 
 Sphenoid. — Division : Body and wings, two faces 
 and four borders. The external surface, continned 
 with the basilar process, shows the vidian fissure, tlie 
 vidian canal, the sub-sphenoidal canals, the orbital 
 hiatus, a surface for the orbital cavity. The internal 
 face shows the crista-galli process, the optic fossa, tlie 
 pituitary fossa, some digital impressions, mastoid fossa^ 
 two fissures — one internal cavernous, and one external, 
 both opening in the three super-sphenoidal canals form- 
 ing the foramen lacerum orbitale,the foramen rotunduni 
 magnum and the foramen patheticum. The borders 
 are : superior, articulated wdth tlie occipital, and pre- 
 senting three notches — one internal, the carotid, contin- 
 uous with the carotid fossa, one external, for the infer- 
 ior maxillary nerve, and one outward, for the middle 
 meningeal artery ; an inferior border assists to form tlie 
 sphenoidal sinus; two lateral borders, articulated with 
 the frontal. Development : two nuclei of ossification. 
 
 Temporal. — Division : Squamous and tuberous por- 
 tions. 
 
 Squamous. — Two faces and a circumference. The 
 external face shows the zygomatic process with a base 
 having a condyle and a glenoid cavity, an external and 
 an internal face, and an apex ; the internal face has a 
 
70 EQDLNE ANATOMY. 
 
 groove for the parieto-temporal caual. The circum- 
 ference is divided into an anterior and posterior border. 
 Development : one nucleus of ossification. 
 
 Tuberous. — Four faces, four borders, a base and an 
 apex. The faces are articular, except the internal, 
 whicli offers the internal auditory hiatus, the internal 
 opening of the aqueduct of Fallopius. Of the borders, 
 one, the postero-external, forms the mastoid crest and 
 the mastoid process ; another, the antero-iuternal, gives 
 attachments to the tentorium cerebelli. The apex is 
 articular. The base shows the external auditory hiatus, 
 the stylo-mastoid foramen, a sharp subuliform process, 
 the mastoid protuberance, and hyoid process. Devel- 
 opment ! two nuclei of ossification. 
 
 Face — Division: Superior jaw, nineteen bones — 
 great superior maxillary, small superior maxillary, 
 nasal, lachrymal, zygomatic, palate, pterygoid, nasal 
 and maxillary turbinated, and vomer. Inferior jaw, 
 one bone — the inferior maxillary. 
 
 Great super-maxillary. — Division : Two faces, 
 two borders, and two extremities. The external face 
 presents the maxillary spine and the inferior open- 
 ing of the super-maxillo-dental canal ; the internal 
 face is a part of the maxillary sinus, and exhibits the 
 palatine duct, a crest for attacliment of the maxillary 
 turbinated, the palatine process and the palatine fis- 
 
HEAD. 
 
 71 
 
 sure. The anterior border is articular ; the posterior 
 has the alveolar cavities, the alveolar tuberosity and 
 the inter-dental space. The superior extremity forms 
 the maxillary hiatus, with three openings, the nasal 
 foramen, super-maxillo dental canal, and palatine canal. 
 The inferior extremity has an alveolus for the tusk. 
 Development : one nucleus of ossification. 
 
 Pre-maxillaky, or small maxillary. — Division : 
 One body and two processes. Body has three faces — 
 the external, or labial, the internal with a notch to 
 form the incisive canal, and the posterior or buccal. 
 Of the three borders, two are internal, the external 
 has three alveoli for the incisive teeth and one notch 
 for the tusk, between the\ the interdental space. 
 Processes : the external is the longest and has two 
 faces, two borders and an apex ; the internal forms 
 the incisive cleft or opening. Development : one 
 nucleus of ossification. 
 
 Palate. — Division : Two faces, two borders and 
 two extremities. The external face has three regions, 
 one superior or orbital with the staphyloid groove, one 
 inferior, forming the roof of the palate, and one mid- 
 dle, articular. The internal face belongs to the nasal 
 cavities. The anterior border has the nasal foramen, 
 the posterior the palatine crest. The superior extremi- 
 ty articulates with the sphenoid, the inferior with that 
 
72 
 
 EQUINE ANATOMY. 
 
 of the opposite side. Development : one nucleus of 
 ossification. 
 
 Pterygoid. — Two faces and two extremities ; the in- 
 ferior extremity has a tendinous pulley. Develop- 
 ment: one nucleus of ossification. 
 
 Zygomatic. — Division : Two faces^ two borders, a 
 base and an apex. The external face has two portions, 
 one anterior orbital, one posterior convex ; the in- 
 ternal face forms the maxillary sinuses. The anterior 
 border is articular, the posterior shows the zygomatic 
 crest ; the base is articular, the apex at the zygomatic 
 arch forms the jugal bridge. Development : one 
 nucleus of ossification. 
 
 Lachrymal. — Division : Two faces and a circum- 
 ference. The external face has two regions, one su- 
 perior or orbital, w^ith the orifice of the lachrymal 
 duct and the lachrymal fossa, and one inferior or facial 
 with tlie lachrymal tubercle. The internal face forms 
 the maxillary and frontal sinuses. The circumference 
 is articular. Development : one nucleus. 
 
 Nasal. — Two faces, two borders, abase and an apex. 
 Tiie external face is smooth; the internal or pos- 
 terior has a crest for the turbinated bone. The ex- 
 ternal border articulates above, but is free below to 
 form the nasal spine ; the internal is articular, as is the 
 base. Development : one nucleus of ossification. 
 
HEAD. 73 
 
 Turbinated Bones. — Tlie anterior, superior or 
 ethmoidal, and posterior or maxillarv. The internal 
 surface is divided by transverse plates ; between 
 these and the surrounding bones are found the 
 three meatuses. Development : one nucleus for 
 each. 
 
 YoMER. — Has two faces, smooth, an anterior border 
 grooved, and a posterior sharp superiorly, thick and ar- 
 ticular inferiorly ; an anterior extremity going to the 
 incisive slit, and a posterior notched and articular. 
 Development: one nucleus of ossification. 
 
 Inferior Maxillary. — Division : Two faces, two boi'- 
 ders and two extremities. External face half smooth and 
 half rough, shows below the mental foramen ; internal 
 face shows the maxillo-dental canal, the myloid ridge 
 and the glenoid surface. The anterior border is 
 alveolar and divided into two parts; the posterior 
 border has also two parts, and offers tlie maxillary 
 fissure and maxillary tuberosity. The superior extrem- 
 ity has a condyle, coronoid process and corono-condy- 
 loid notch ; the inferior forms the body, with an anter- 
 ior face, buccal, and a posterior, labial. Its circumfer- 
 ence has the alveoli for the incisive teeth. The neck 
 of the bone is at the iunction of the two branches. 
 Development : two nuclei of ossification. 
 
74 EQUINE ANATOMY. 
 
 SYIVDESIWOLOGY. 
 
 Temporo-maxillary joint— Double condyloid. On 
 the temporal, a condyle, glenoid cavity and snpra-con- 
 dyloid process ; on the raaxillary, a condyle, inter- 
 articiilar meniscus, capsula** ligament. Motions : De- 
 pression, elevation, lateral motion, horizontal gliding. 
 
 Otlier joints are all synarthrodial, sutura. 
 
 MYOLOGY. 
 
 Facial Region,— Thirteen muscles. 
 
 1. Lawai^is. — Synonyms. Orbicularis oris, (P). 
 Attachments : Ko bony attachments. Action : Con- 
 strictor of the lips. 
 
 2. Alveolo-labialis. — Synon^ans. Buccinator, (P). 
 Buccinator and molaris, (L). Attachments : Alveolar 
 tuberosity, superior and inferior /maxijlary. Action : 
 Belated to mastication. ^^<*<^^ Q^^^ ^ ' 
 
 ABiALis,-— Synonyms. Zysiamaticus, 
 3 : burracejor the mas^ei'^and com- 
 
 3. Zygomatico-labialis,- 
 (P). Attachments' 
 missure of the lips. Action : Pulls the commissure 
 backwards. 
 
 4. Lachrymo-labialis. — Synonyms. Not mentioned 
 by P. Inferior palpebral, (L). Attachments: Lach- 
 rymal and zyo'omatic'bones, cellulau fasciafj30verin2r the 
 alveolo-labialis.-^ Action : Corrugates tlie skin below 
 tl^e eye. j> ' 0' 
 
HEAD. 75 
 
 5. SuPERNASO-LABiALis. — SynonjiTis. Levator labii 
 siiperioris alceque nasi, (P). Fronto-labialis, (L). At- 
 tachments : Frontal and nasal bones, external alae of 
 the nose and commissure of the lips. Action : Elevates 
 the alee of the nose, the upper lip and tlie commissure. 
 
 6. StiPER-MAxiLLO-LABiALis. — Sjuonyms. Nasalis 
 longns labii siiperioris, (P). Attachments : Super- 
 maxillary and zygomatic bones to upper lip with its 
 congener. Action : Raises the upper lip directly or 
 sideways. 
 
 T. Great suPER-MAxiLLO-NASALis.-Synonyms. Dila- 
 tator naris lateralis, (P). Attachments : The external 
 face of the superior maxillary and the external wing 
 of the nostril. Action : Dilates the external orifice 
 of the nasal cavity. 
 
 8. Small super-maxillo nasalis. — Synonyms. Na- 
 salis brevis labii superioris, (P). Attachments : The 
 premaxillary bone, the nasal spine, and the skin of 
 the false nostrils, which it dilates. 
 
 9. Transversalis nasi. — Synonyms. Dilatator naris 
 anterior, (P), Attachments : Nasal cartilages. Action : 
 Dilatator of the nostrils. 
 
 10. Middle (intermediate) anterior. — Synonyms. 
 Depressor labii superioris, (P). Incisive muscle of the 
 upper lip, (L). Attachments : The pre-maxillary, and 
 anterior appendix of the inferior turbinated bone. 
 
76 EQUINE AN^ATOMY. 
 
 Action : Dilatator of the entrance of the nasal fossa. 
 
 11. Maxtllo-labialis. Synonyms. Depressor labii 
 inferioris, (P). Inferior maxillo labialis, (L). Attach- 
 ments : Anterior border of the lower jaw and the skin 
 of the lower lip. Action : Pulls the lower lip down 
 directly or on one side. 
 
 12. Mento-labialis. — Forms the base of the ronnded 
 protuberance beneath the lower lip. No bony attach- 
 ment. 
 
 13. Middle (intermediate) posterior. — Synonyms. 
 Levator menti, (P). Incisive muscle of the lower lip. 
 (L). Attachments : External surface of the body of 
 the lower jaw and to the mento-labialis. Action : 
 Elevator of the lower lip. 
 
 Masseterine Region.— Five muscles. 
 
 1. Masseter. — Synonyms. Zygomatico-maxillaris, 
 (G:). Attachments : Zygomatic crest, upper half of 
 external surface of inferior maxillary branch. Action: 
 Elevator of the lower jaw. 
 
 2. Temporal. — Synonyms. Temporo-m axillaris, (G). 
 Attachments : Temporal fossa, orbital hiatus, coronoid 
 process and anterior border of the branch of the lower 
 jaw. Action : Elevates the jaw. 
 
 3. Internal pterygoid. — Synonyms. Pterygoid- 
 eus internus, (P). Attachments : The palatine crest, 
 subsphenoidal process, hollow of the internal face of the 
 
HEAD. 77 
 
 brand) of the lower maxillary. Action : Elevates and 
 moves the jaw laterally. 
 
 4. External pterygoideus. — Attachments : Inferi- 
 or face of the sphenoid, subsphenoidal crest, neck of 
 the condyle of the inferior maxillary. Action : Pulls 
 the maxilla forward directly or sideways. 
 
 5. DiGASTRicus. — Synonyms. Stylo-maxillaris, (G). 
 Attachments : Styloid process of the occipital, curved 
 portion of the lower maxilla, internal face of same 
 bone, and straight portion of its posterior border. 
 Action : Fulls the jaw backwards, and at the same 
 time depresses it. 
 
 SPLAIVTMOLOGY. 
 
 IVasal Cavities.^ IS'umber, two. Division : Nostrils, 
 nasal fossa proper and sinuses. 
 
 Nostrils. — Two lips or borders united by two com- 
 missures. The superior commissure shows the false 
 nostrils ; the inferior the opening of the lachrymal duct. 
 Structure: cartilages; muscles, viz: the transversalis nasi, 
 pyramidalis nasi, super-maxillo-nasalis parvus, middle 
 anterior, and supernaso-labialis ; integuments; blood 
 vessels, viz : superior coronary, nasal and palato-labial 
 arteries ; nerves, branches of tlie fifth and seventh 
 cranial pairs. 
 
 Nasal foss^ proper. — Divisions : Four walls and 
 
'%* 
 
 78 
 
 EQUINE ANATOMY. 
 
 two extremities* The superior wall or roof ; the in- 
 ferior or floor with Jacobson's apparatus ; the lateral 
 external with the turbinated bones and meatuses ; the 
 middle meatus having an opening of communication 
 with the sinuses ; the lateral internal is formed by 
 the septum nasi. The anterior extremity forms tlie 
 nostrils ; the posterior looks into the pharynx. Struc- 
 ture : nasal, maxillary, frontal, palate, ethmoid and 
 turbinated bones, middle septum of the nose ; pituit- 
 ary membrane; blood vessels, the ophthalmic and 
 nasal arteries ; nerves, first and fifth pairs of cranial 
 nerves. 
 
 Sinuses. — Five: the frontal, sphenoidal, ethmoidal 
 and two maxillary. All communicate through the 
 middle meatus. The inferior maxillary sinus opens 
 by itself into the nasal fossa. They are all lined by 
 mucous membrane and develop with age. 
 
 Buccal Cavity. — Division : Six regions. 
 
 a. Lips. Superior and inferior, united by com- 
 missures. Two faces; two borders, one adherent 
 and one free. Structure : skin, mucous membrane, 
 muscles, viz: tlie orbicularis, super-maxillo labialis, 
 super-naso labialis, great super-maxillo nasalis, tufts 
 •of the chin and posterior intermediate ; glands, the 
 labial ; blood vessels, the palato-labial and coronary 
 arteries ; nerves, the fifth and seventh cranial pairs. 
 
HEAD. 79" 
 
 h. Cheeks. Two faces, on the internal the opening 
 of Stenon duct. Structure: skin, mucous membrane; 
 muscles, viz: the alveolo-labialis, and the masseter; 
 blood vessels, the maxillary, coronary and buccal 
 arteries ; nerves, the fifth and seventh pairs of cra- 
 nial nerves. 
 
 c. Palate. Its face is covered with about twenty 
 furrows curved backwards. Structure : bone, the pa- 
 late and great maxillary; membranes, one fibrous, one 
 mucous ; vessels, the palato-labial artery ; nerves, fifth 
 pair of cranial nerves. 
 
 d. Tongue. — Situated in the lingual canal and at- 
 tached to tlie hyoid apparatus. 
 
 Hyoid apparatus, hyoid bone. — Formed of seven 
 pieces, a body and three branches. The body has an 
 anterior process or spur, and two lateral branches. It 
 is developed by three nuclei of ossification. The 
 branches; two small, with articular facets at both ex- 
 tremities ; two long, with faces smooth ; an anterior 
 and posterior border ; one inferior extremity articulated 
 with the middle nucleus or third branch ; one superior 
 articulated with the temporal bone. 
 
 Muscles. — Five in pairs, and one single. 
 
 1. Mylo-hyoideus. — Attached to mylo-hyoid line of 
 the inferior maxillary, to anterior appendix of the body 
 of the hyoid bone, which it eleva 
 
 L'^ 
 
 "'^in^^^.^-^TX'^ ^i^M^0L4i^A^ 
 
80 jU^'^^'^'^^^ EQUlf^^Tl^r^. 
 
 2. Genio-hyoideus. — Attached to the genial surface 
 and to the anterior opening of the body of the hyoid 
 bone which it draws forward. 
 
 3. Stylo-hyoideus — Synonyms. Hyoidens magnus, 
 (P). Kerato-hyoideus magnus, (L). Attached to 
 the supero-posterior angle of the long branch, to the 
 cornua of the os hyoides, which it draws backwards. 
 
 4. Kerato-hyoideus. — Synonyms. Hyoideus par- 
 vus, (P). Small kerato-hyoideus, (L). Attached to 
 
 Vj the posterior border of the cornu^and the extremity of 
 -J the styloid bone, toSie superior border of the thyroid 
 
 wino-. Action: Brini>;s the two branches too^ether. 
 \^ 5. OcciPiTO-HYOiDEUs. — Attached to the styloid pro- 
 
 cess of the occipital, the superior border of the long 
 branch of the hyoid. Action : Swings the bone down- 
 wards and backwards. 
 
 6. Transversalis-hyoideus. — Attachments: Supe- 
 rior extremity of the small branches. Action : Brings 
 them together. 
 
 External coneormation of the tongue. — Three 
 faces, three borders and two extremities. Superior face, 
 papillae, foramen coecum of Morgagni ; lateral faces, 
 large papilla and opening of the lingual glands. The 
 two superior borders are thick; the inferior is fixed at 
 the bottom of the intermaxillary space ; the anterior 
 extremity or free part is attached to the maxillary by 
 
the anterior pillar or froenum linguae ; the posterior 
 extremity shows a median mucous fold going to tlie 
 epiglottic cartilage ; two lateral folds called the pos- 
 terior pillars of the tonp*ue, and the amvij-dalpidfcavi- 
 ties. Structure : mucous membrane with hlifonu, '^f^ ^ 
 X-fungiform and calciform papillse. Muscles : five. ^ 
 
 1. Stylo-glossus. — Synonyms. Hyo-glossus longns, 
 (P). Kerato-giossus externus, (L). Attachments : 
 External surface of the long branch of the hyoid and 
 near the tip of the tongue. Action : Fulls the tongue 
 backwards or sideways. 
 
 2. Great hyo or basio-glossus. — Synonyms. Hyo- 
 glossus brevis, (P). Hyo-glossus, (L). Attachments : 
 The extremity of the cornu and the anterior apex of 
 the hyoid bone to near the superior face of the tongue, 
 which it retracts. ^^ ^^^^^ — j /C-^t^t^ 
 
 3. Genio-glossus. — Synonyms. Genio hyo-glossus, 
 (P). Attached to the lower jaw near the symphysis, 
 and to the upper surface of the tongue. Action : 
 Carries the tongue forwards, backwards and down- 
 wards in the buccal cavity. 
 
 4. Small hyo-glossus. — Synonyms : Lingualis, (P). 
 Attachments: Inner side of the articulation of the two 
 branches of the hyoid bone, to the superior face and 
 sides of the tona'ue. Action : Contracts and retracts 
 
 C^-^ 
 
 W^^r^^ 
 
82 EQUINE ANATOMY. 
 
 5. Fharyngo-glossus. — Attachments : The lateral 
 walls of the pharynx and posterior part of the tongue. 
 Glands : racemose and follicular. Blood vessels, the 
 lingual and sub-lingual arteries. Nerves, the lingual, 
 glosso-pharyngual and gre^^t hypo-glossus. 
 
 e. Soft Palate — Velum pendulum palati. — Two 
 faces : the anterior united to the tongue by the poste- 
 rior pillars of that organ; the posterior or pharyngeal 
 with longitudinal ridges. Two lateral borders: one 
 anterior, all attached on bones ; one posterior border, 
 embracing the epiglottic cartilage with the two poste- 
 rior folds, forming the posterior pillars of the velum 
 palati. It closes the isthmus of the fauces. Structure: 
 a fibrous membrane and four muscles : 
 
 1 . Pharyngo-staphyleus. — Synonyms. Palato-sta- 
 phyleus, (P). Attachments : Coiitinujpus to the fi^'ous 
 membrane. T^^ct&f Tofretcnes the velum palati. 
 
 2. Palato-staphyleus. — Synonyms. Staphyleus,(G). 
 Circumflex palati, (P). Attaclied to the palatine arch 
 and the free border of the septum, which it raises. 
 
 3. Perystaphyleus externus. — Synonyms. Ten- 
 sor palati, (P). Attachments : The styloid process of 
 the temporal, and fibrous layer of the velum palati. 
 Action : Tensor and depressor. 
 
 4. Perystaphyleus internus. — Synonyms. Stylo- 
 pharyngeus, (P). Attachments: Same as above. Act- 
 
HEAD. 
 
 83 
 
 ion: Elevator of the soft palate. Glands: situated 
 on the anterior face directly under the mucous mem- 
 brane. Mucous membranes : two in number, one on 
 the anterior and one on the posterior face. Blood ves- 
 sels, the pharyngeal and staphyline arteries. Nerves, 
 fifth pair of cranial nerves and ganglion of Meckel. 
 
 y. Teeth. — Definition : passive organs of mastication. 
 
 General characters: general disposition form two 
 parabolic arches interrupted on each side by interdental 
 space. These arches present the incisive teeth in front, 
 the tusks behind them, and the molars in the lateral 
 and posterior parts of the dental arches. External 
 conformation : they have a root or fang encased in an 
 alveolus, and a crown exposed. Structure : Ivory or 
 dentine forming the base of the tooth, and surrounds 
 the internal cavity wdiich is filled by the pulp ; it is 
 hollowed with canaliculi, imbeded in amorphous mat- 
 ter. Enamel forms the outside covering of the free 
 part of the tooth, consisting of little prismatic hexag- 
 onal rods denticulated on theii* faces. Cement irregu- 
 larly spread over both the ivory and enamel, with 
 the structure and properties of spongy bone-substance. 
 Dental pulp, fibrillar and nuclear mass filling the in- 
 ternal dental cavity, and receiving blood vessels and 
 nerves. The gum, a portion of the buccal mucous 
 membrane, surrounds the neck of the tootii. An 
 
84 EQUINE ANATOMY. 
 
 alveolar dental periosteum lines the cavity of tlie alve- 
 olus and the external face of the cement of the fang. 
 Development : the dental follicle, or a membrane con- 
 taining at its bottom the dental pulp and having in its 
 upper part the enamel germ, attached to the guber- 
 naculum dentis. Considering their epoch of develop- 
 ment, teeth are divided into caducous, temporary or 
 milk, and replacing or persistent teeth. 
 
 Incisors. — Six in each jaw. Divided into pincers, 
 middle teeth or nippers, intermediate or dividers, and 
 corners. The superior surface exhibits the external 
 dental cavity which, when worn, shows the central and 
 surrounding enamels ; and in older animals the dental 
 star; and lattei) the >5Lternal dental cavity, obliterated. 
 
 Canines or tusks. — Two in number, are found, in 
 solipeds, in males only : they seldom are shed, and 
 grow but once. 
 
 Molars. — Twelve on each jaw; six on each side. 
 The surface of these teeth is inclined from inwards 
 outwards for the lower jaw, and vice versa for the 
 upper one. They present the aspect of a grinding 
 surface, made irregular by the arrangement and pro- 
 jection of the enamel. The first three molars are 
 caducous. "s::^^^^^^^^^«2E^5^i<sd5!>»^^^^ 
 
 Eye. — Organ of sight, is composed of accessory and 
 essential organs. c^4,^^i?g<I^ 
 
 ^ 
 
 <^%,^a^t-*.-c <r^ '^ 
 
 c - J" ^ 
 
 o 
 
 
HEAD. 85 
 
 Accessory organ — orbital cavity. — Formed by 
 the orbital process, the frontal, laclirymal, zygomatic 
 bones, and part of the zygomatic process of the tem- 
 poral. It is closed by the ocular sheatli, a fibrous en- 
 velop attached on the orbital hiatus and forward on 
 the internal face of the orbit, and surrounding the 
 seven muscles of the globe of the eye. 
 
 1. Posterior rectus or retractor-oculi — Attach- 
 ments: Rourid.tlie optic foramen, external face of the 
 sclerotic. Action : Pulls the globe backwards. 
 
 2. Superior, inferior, external and internal rec- 
 ti. — Attachments: In the bottom of the ocular sheath, 
 and external surface of the sclerotic. Action : Turns 
 the pupillary opening upwards, downwards, outwards 
 or inwards. 
 
 3. Great oblique or obliquus superior oculi. — 
 Attachments : The bottom of the orlnt and the ex- 
 ternal surface of the sclerotic. Action : Pivots the 
 •eye inwards and upwards. 
 
 4. Small oblique or obliquus jnferior oculi. — 
 Attachments : The lacrymal fossa and external face of 
 the sclerotic. Action : Pivots the eye outwards and 
 downwards. 
 
 Eye-lids. — One superior, and one inferior. They 
 have two surfaces, and are lined internally by the con- 
 junctiva forming the conjunctival sinus ; they have 
 
86 EQDINE ANATOMY. 
 
 two borders united by commissures or canthi, the free 
 border showing the openings 'of the Meibonian glands. 
 Structure : 1 — fibrous plate having on its free border 
 2 — the tarsus ; 3 — muscles, the orbicularis-palpebrum 
 and orbito-palpebrum ; 4 — integuments represented by 
 the "skin and conjunctiva; 5. — ej^e-lashes; 6 — Mebo- 
 nian glands. 
 
 Membrana nictitans or third eyelid, or winking 
 EYELID. — A fibro cartilage situated at the inner angle 
 of the eye. 
 
 Lachrymal apparatus — lachrymal gland. — Situ- 
 ated on the superior face of the globe, having numerous 
 ducts called hygrophthalmic canals. 
 
 Lachrymal cardncula. — A round body in the na- 
 sal angle of the eye. 
 
 Puncta lachrymalis. — Little openings on each eye- 
 lid at the nasal commissure. 
 
 Lachrymal ducts. — Continuation of the puncta, and 
 emptying in the 
 
 Lachrymal sac. — Little reservoir lodged in the 
 lachrymal fossa and continuous with the lachrymal 
 duct ; opening at the lower commissure of the nostrils 
 by one and sometimes two orifices. 
 
 Essential organ — globe or the eye. — Divided 
 into membranes and humours or media. 
 
 Membranes — 1. Sclerotic. — Two faces, the external 
 
HEAD. 8T 
 
 covered by the muscles and adipose tissue, the internal 
 lined by the clioroid. The anterior 0})ening is contin- 
 uous with the cornea, the posterior is run through by 
 the optic nerve. Structure : connective tissue mixed 
 with elastic fibres and pigment. 
 
 2. Cornea. — Two surfaces and a circumference. 
 Structure: three layers ; an external, the conjunctival 
 epithelium ; a middle, composed of fasciculi of con- 
 junctival fibrilla, between which is a liquid amorphous 
 substance ; and an internal, portion of the membrane 
 of the aquous humour. 
 
 3. Choroid. — Divided by the ora serrata into two 
 zones, one posterior or choroid, internally in contact 
 with the retina and externally with the sclerotic ; one 
 anterior or ciliary, formed by ciliary circle, and a ciliary 
 body, from which hangs the ciliary processes. Structure : 
 four layers ; an external, composed of connective and 
 elastic fibres with pigmentary cells; a second layer, 
 vascular and nervous, with pigmentary cells ; a third 
 layer, or of Ruysch, formed of amorphous substance ; 
 and an internal layer, composed of hexagonal cells 
 containing pigment. 
 
 4. Iris. — A septum in front of the crystalline lens, 
 with the pupil in its centre, through which appears 
 the " soot-balls " or corpora nigra, portions of the 
 uvea which covers the posterior face of the iris. 
 
88 EQUINE ANATOMY. 
 
 Structure : a proper menbrane with unstriped muscular 
 fibres, an anterior epithelial layer, and a posterior 
 epithelial or uvea. 
 
 5. Retina. — An expansion of the optic nerve. Struc- 
 ture : connective tissue forming the external and inter- 
 nal limitary membrane and nerve elements, forming 
 seven layers : 1 — one of rods and cones ; 2 — external 
 granular ; 3 — intermediate ; 4 — inner granular ; 5 — 
 molecular ; 6 — ganglionic ; 7 — of fibres of optic 
 nerves. 
 
 Humours or media. — Crystalline lens, transparent 
 lens, enveloped by the crystalline capsula ; vitrous 
 humour covered by the hyaloid membrane; aquous 
 humour secreted by the membrane of Descemet or 
 Demours. 
 
 Ear. — Division : External, middle and internal 
 ear. 
 
 External. — Composed of: 1 — external auditory 
 canal, formed by the petrous portion of the temporal 
 bone; 2 — the concha or pavillion formed by the con- 
 chal, annular and scutiform cartilages, and moved by 
 ten muscles : 1 — Zygomatico auricularis. Synonyms. 
 Attolens anterior, (P). Temporo- auricularis, (L). At- 
 tachments : Zygomatic process of the temporal base of 
 the concha and external border of the scutiform carti- 
 lage. Action : Fulls the ear forward. 2 — Temporo- 
 
HEAD. 89 
 
 auricularis externus Synonyms. Attoleris maximus, 
 .(P). Attachments : The parietal crest and the inter- 
 nal border of the scutiform and conchal cartilages. 
 Action : Adductor of the concha. 3 — Scuto-auricu- 
 laris externus. Sjmonyms. Anterior conchse, (P). 
 Attachments : External face of the scutiform and the 
 internal side of tlie concha. Action: E-otator out- 
 wards. 4 — Three cervico-auricularis. Synonyms. Re- 
 tralientesaurem, (P). Attachments : Tlie cervical liga- 
 ment, the superficial to tlie posterior face of the con- 
 cha, tlie middle on the outside of the base, and the 
 deep at the base of the conchal cartilage. Action : 
 Pull the ear backwards and in rotation outwards. 5 — 
 Parotido auricularis. Synonyms. Abducens or depri- 
 mens aurem, (P). Attachments : The parotid gland 
 and at the base of the concha. Action: abductor of 
 the external ear. 6 — Temporo-auricuhiris internus. 
 Synonyms. Attolens posterior, (P). Attachments; 
 On the median crest origin of the parietal crest, and 
 on the internal side of the concha. Action : Abductor 
 •of the ear. 7 — Scuto-auricularis internus. Synonyms. 
 Posterior conchge, (P). Attachments : On the internal 
 face of the scutiform and at the base of the concha. 
 Action : Pivots the ear outwards and backwards. 8 — 
 Mastoido-auricularis. Attachments on the rim of the 
 •external auditory hiatus and the base of the concha. 
 
90 EQUINE ANATOMY. 
 
 Action : Constricts the cartilaginous tube of the ear. 
 
 Middle ear or tympanum. — Division : An external 
 wall formed by the membrana tympani, an internal with 
 the fenestra ovale separated by the promontory from 
 the fenestra rotunda. The circumference is occupied 
 by the mastoid cells. Internally are found four bones, 
 the malleus, incus, orbiculare and stapes ; they are 
 moved by the internal muscle of the malleus and the 
 muscle of the stapes ; this cavity is lined by a tine 
 mucous membrane and communicates with the pharynx 
 by the Eustachian tube or guttural ducts of the tym- 
 panum, a long canal cleft inferiorly, through which 
 the mucous membrane escapes and descends to form the 
 guttural pouches. 
 
 Internal ear or labyrinth. — Division : Osseous 
 labyrinth ; 1 — a vestibule with eight orifices, the fen- 
 estra ovale, five openings of the semi-circular canals, 
 the opening of the seala cochlea and the forami- 
 na for the branches of the acoustic nerve ; 2 — the 
 semi-circular canals, divided into superior, posterior and 
 external. 3 — The cochlea or snail shell twisted round 
 the modiolus and divided by the lamina spiralis into 
 superior and inferior scalse. 
 
 Membranous labyrinth. — 1. Membranous vetibule : 
 formed by two sacs, the superior or utriculus, and the 
 inferior or sacculus ; and composed of two layers, the 
 
HEAD. 91 
 
 external cellular, the internal epithelial. 2 — Mem- 
 branous semi-circular canals, corresponding to the 
 osseous canals. 3 — Membranous cochlea, forming 
 three cavities: one inferior tympanic, one superior or 
 vestibular, one middle or auditory, containing the organ 
 of Gos^. € cn^ 
 
 Fluids of labyrinth: that of the membranous laby- 
 rinth, or endolymph ; that of the osseous labyrinth, 
 or peri-lymph. 
 
 Cranium* — Formed by the frontal, parietal, occipi- 
 tal, ethmoid, sphenoid and temporal bones. Division : 
 Four planes and two extremities. Superior plane 
 presents the internal occipital protuberance with its 
 lateral and median crests. Inferior plane, the basilar 
 groove, pituitary fossa, optic fossa, foramen lacerum, 
 cavernous sinuses, maxillary fissures and mastoid fossa. 
 Lateral planes covered with digital impressions. Poste- 
 rior extremity, occiptal foramen. Anterior extremity, 
 the crista-galli process, the ethmoidal fossa and the 
 cribriform plate of the ethmoid. 
 
 It is lined by three meninges : The external or dura 
 MATER, a fibrous membrane forming three folds: the 
 falx cerebri between the cerebral hemispheres, which, in 
 old animals, has as its posterior extremity the Pacchi- 
 onian glands or meningeal granulations ; the tentorium 
 cerebclli between the cerebrum and cerebellum ; the 
 
92 EQUINE ANATOMY, 
 
 suprasphenoid or pituitary fold, which circumscribes- 
 the sella turcica. The cranial dura mater is more or 
 less adherent to the bone, and is lined by the parietal 
 layer of the arachnoid ; it gives prolonged sheaths to 
 the nerves. 
 
 The middle or arachnoid is a serous membrane 
 with a parietal and a visceral layer, enclosing a cavity 
 by its internal face, perforated by the roots of the 
 nerves and blood vessels. It shows iilaments uniting 
 it to the pia mater ; passes over the circumvolutions of 
 the encephalon, leaving spaces or confluents containing 
 the sub-arachnoid fluid, a slightly yellow or colorless 
 but limpid and transparent liquid. 
 
 The internal or pia mater, a cellulo-vascular struc- 
 ture, which, by its external face, furnishes the neuril- 
 emma of the nerves and filamentous threads to the 
 dura mater. From its internal face rise blood vessels 
 dipping into the nervous substance. 
 
 Encephalon. — Yolume, closely that of the cranium. 
 Weight, about twenty-two or twenty-three ounces. Di- 
 vision : Isthmus, cerebrum and cerebellum.*^ yL^>v^ 
 
 Isthmus. — a. External surface : four faces and two 
 extremities. Inferior face presents annular protuber- 
 erance or pons Varolii or mesocephalon, crura-cerebri 
 or pedunculum cerebri, rachidian bulb or medulla ob- 
 longata ; superior face shows the upper face of the 
 
HEAD. 93 
 
 medulla oblongata, peduncnliim cerebelli or crura cere- 
 belli, valve of Yieussens, corpora quadrigemina and thai- 
 ami optici; lateral faces present the proiile of the 
 medulla oblongata, of the pons Varolii, of the pcdunc- 
 ulum cerebri and cerebelli, of the corpora quadrigemina 
 and thalami optici ; posterior extremity is continuous 
 with the spinal marrow ; anterior extremity passes into 
 the corpora striata. 
 
 1. Medulla OBLONGATA. — Division: Four faces: in- 
 ferior shows the corpora pyramidalia, a transverse band, 
 some arciform fibres, the corpus olivare, the origin of 
 the sixth cranial pair, of glosso pharyngeal and of the 
 pneumogastric ; superior face is covered by the cerebel- 
 lum, forms the floor of the fourth ventricle and shows 
 the calamus scriptorius and the corpora restiforma; 
 lateral face exhibits the profile of the corpora resti- 
 forma and corpora pyramidalia. 
 
 2. Pons Yarolii with its two borders and two ex- 
 tremities, which form the middle crura cerebelli. 
 
 3. Crura cerebri. — Separated from each other by 
 the interpeduncular fissure which bifurcates to circum- 
 scribe forward the mamillary or pisiform tubercle, lim- 
 ited behind by the pons Yarolii, in front by the optic 
 nerves, laterally and above by the corpora quadrigem- 
 ina and thalami optici; it forms laterally the band of 
 Keil or lateral triangular fasciculus. 
 
94 equine anatomy. 
 
 4. Crura cerebelli. 
 die is the largest; the posterior tne sii^aiiest f tney cim^/ 
 
 dh-ectly into the cerebellum. ' ^ ^y^ZJi^^^^^^^^^f!^^ 
 
 5. Yalve of Vieussens. — Thin lamella, uniting the / 
 two anterior cerebellar peduncles. 
 
 6. Corpora quadrigemina. — Anteriorly the tuber- 
 cula nates, and posteriorly the testes uniting outwardly 
 to the corpus geniculatum externum. 
 
 7. Thalami optici. — Inclined inwardly to form a 
 deep fissure containing the anterior peduncles of the 
 pineal gland ; this fissure presents at its extremities 
 the anterior and posterior common openings ; outward- 
 ly shows the corpus geniculatum externum and inter- 
 num ; in front it exhibits the semi-circular band or taenia 
 semi-circularis. 
 
 8. Pineal gland or conarium. — Reddish-brown 
 mass resting on the posterior common opening. 
 
 9. Pituitary gland. — Synonyms. Hypophysis cer- 
 ebri, supra sphenoidal appendage ; fixed to the inter- 
 pedunculum fissure by the pituitary stem and tuber- 
 cinereum. 
 
 (h.) Internal conformation. — Three cavities. 1. — 
 Middle ventricle of the thalami optici. Division : Two 
 walls, a floor, a roof with the anterior and posterior 
 common openings separated by the grey commissure. 
 The posterior extremity is continuous with the aque- 
 
. (P>/'^^ HEAD. 95 
 
 duct of Sylvius ; the anterior presents the lamina cine- 
 rea or grey root of the optic nerves ; 2 — Aqueduct of 
 Sylvius posteriorly opens into the fourth ventricle ; 
 3 — Posterior cerebellar or fourth ventricle closed su- 
 periorly by the valve of Yieussens and of Renault. 
 
 {c.) Stkucture : formed of three fasciculi of white 
 substance, a superior or corpora restiforma, an inferior 
 or corpora pyramidalia and a lateral or intermediate; 
 the grey substance is found in the floor of the fourth 
 ventricle, the crura cerebri, the lateral or intermediate 
 fasciculi of the bulb, the corpora quadrigemina, the 
 thalami optici and in the annular protuberance. 
 
 Cerebellum. — {a.) External surface : one middle 
 lobe forming the anterior and posterior vermiform 
 processes ; two lateral lobes, beneath which the cho- 
 roid cerebellar plexus is applied. Its external surface 
 is covered with sulci ; (Z>.) Internal surface on section 
 shows the arbor vitae and corpus rhomboideum. 
 Structure : the white substance is internal and ramify- 
 ing, the grey substance forms cortical layer. 
 
 Cerebrum. — Division : Two lateral hemispheres. 
 {a.) External surface shows: 1 — Interlobularor longitu- 
 dial fissure, whicli extends down to the corpus callosum 
 and is bound posteriorly by the fissure of Bichat, and 
 lodges the great vena Galeni and falx cerebri ; 2 — ce- 
 rebral hemispheres, with four faces covered with con- 
 
06 EQUINE ANATOMY. 
 
 volutions, and showing the mastoid lobe, the fissure of 
 Sylvius and the olfactory or ethmoidal lobes ; an ante 
 rior extremity lodged in the ethmoidal fossa, a posterior 
 resting on the cerebellum. 
 
 (h.) Internal surface. 1 — Corpus callosum, an arch 
 thrown over the lateral ventricles uniting the two 
 hemispheres, and offering on its superior face the 
 tractus longitudinalis ; 2 — lateral or cerebral ventricles. 
 Division : An anterior and a posterior or reflexed por- 
 tion ; they are separated by the septum lucidum, a thin 
 median lamella, standing vertically between them, and 
 by the fornix or trigonum cerebralis, which serves to 
 support the septum. On the floor of the lateral ven- 
 tricles are seen from forward backwards ; 1 — the cor- 
 pora striata, showing inwardly and posteriorly the 
 taenia semi-circularis in which floats the choroid plexus ; 
 2 — the hippocampi or cornu Ammonis, occupying the 
 floor of the anterior region of the lateral ventricle, and 
 is prolonged in its reflected portion and having their 
 external extremities resting on the mastoid lobes ; 3 — 
 the velum interpositum or choroid plexus, a vascular 
 expansion of the pia mater penetrating in the ventri- 
 cles by the transverse fissure. A fine membrane, the 
 ventricular arachnoid, lines the cavity of the ventricles ; 
 it secretes a liquid analogous to the cerebro-spinal fluid. 
 Structure : the grey substance forms the cortical layer 
 
HEAD. 97 
 
 of the cerebral convolutions. The white substance 
 
 forms in the hemisphere the centrum ovale of Yieussens. 
 
 Intermaxillary space or throat.— Pharynx. — Its 
 
 cavity presents seven openings : two for the nasal cav- 
 ities ; two for the Eustachian tubes ; one for the larynx ; 
 one for the oesophagus, and one for the isthmus of the 
 throat or of the fauces. Structure : 1 — a mucous mem- 
 brane covered bv yel low el astic fibres ; 2 — seven muscles : 
 a. palato pharyni^eus or pharyngo-staphyleus (described 
 in soft palate) 'Jj^h. Pterygo pharyngeus or superior 
 constrictor. S^^^iiyins. Pallito pharyngeus. At- 
 tachments : Pterygoid process, posterior and superior 
 face of the pharynx. Action : Perfect constrictor of 
 the pharynx 'A4c. Hyo-pharyngeus or first middle con- 
 strictorfcrZ. Thyro-pharyngeus or second middle con- 
 strictor iJe. Crico-pharyngeus or inferior constrictor. 
 Attachments ; The first to the corner of the os hyoides, 
 the second from the external surface of the thyroid 
 cartilage, the third from the cricoid cartilage, and all 
 
 three endino; on the median fibrous line above the 
 
 * I* 
 pharynx, are all constrictors of the pharynx jU-y. Ai'yte-^-^fcJt** 
 
 no-pharyngeus. Attachments : The posterior border of 
 
 the arytenoid to the origin of the oesophagus 'Jfg. Styio- 
 
 pharyngeus. Attachments : Inside the great branch of 
 
 the hyoid bone to the side of the pharynx. Action : 
 
 Dilator.jro 3 — Blood vessels, the pharyngeal and thyroid 
 
98 EQUINE ANATOMY. 
 
 arteries. 4 — Nerves : glosso-pharyngeal, pneumo-gas- 
 tric, great sympathetic. 
 
 Larynx* — Structure : five cartilages. 1 — Cricoid, 
 with an external face, presenting two conca^'e articular 
 f acettes, and an internal face smooth ; a superior and in- 
 ferior circumference ; 2 — Thyroid. Division : A body 
 and two wings, the superior border of which presents 
 a mean of articulation with the hyoid and a notch for 
 the superior laryngeal nerve ; 3 — Epiglottic, with 
 two faces, two borders, a summit and a base, the bor- 
 ders having prolongations or cartilages of Wrisberg 
 extending backwards ; 4 — Arytenoid, two, whose exter- 
 nal face is divided by a ridge in two portions ; superior 
 and anterior borders unite with their congeners ; pos- 
 terior border projects into the larynx ; and inferior 
 gives attachments to the vocal cord. 
 
 Articulations. — 1 — the thyroid cartilage to the 
 hyoid bone, by the extremities of the cornua and 
 through the medium of the thyro-hoid membrane ; — 2 
 the thyroid and cricoid cartilages by two small arthro- 
 dia and the crico-thyroid membrane ; 3 — the two ary- 
 tenoids by their superior borders; 4 — the arytenoid 
 and the cricoid cartilages by small movable arthrodia ; 
 5 — arytenoid to the thyroid by the vocal cords ; 6 — 
 the epiglottic to the thyroid cartilages by amphiar- 
 throsis ; T — the epiglottic to the arytenoids by the 
 
HEAD. 99 
 
 superior vocal cords ; 8 — the cricoid cartilages to the 
 tracliea by the crico-tracheal elastic membrane. 
 
 Muscles. — Three extrinsic : 1 — Sterno-thyroideus 
 (see inferior cervical region) ; 2 — Hyo-tliyroidens. 
 Attachments : "Whole extent of the hyoid cornu, exter- 
 nal face of the thyroid cartilages. Action : Carries 
 the larynx forward and upward ; 3 — Hyo-epiglottideus. 
 Attachments : Superior face of the body of the hyoid 
 bone, and antero-inferior face of the epiglottic cartil- 
 ages. Action : Pulls the epiglottic cartilage to normal 
 position. Five intrinsic : 1. — Crico-thyroideus. At- 
 tachments : from the cricoid to the posterior border of 
 the thyroid, it shortens the larynx ; 2. — Posterior cri- 
 co-arytenoideus. Attacliments : bezel of the cricoid, 
 the median crest and the posterior tubercle of the ary- 
 tenoid, it dilates the entrance of the larynx ; 3 — 
 Lateral crico-arytenoideus. Attachments : Side of the 
 anterior border of the cricoid, and tubercle of the ary- 
 tenoid cartilage, it constricts the larynx ; 4 — Thyro- 
 arytenoideus. Attachments : Internal surface of the 
 ala of the thyroid and on the arytenoid ; it is a con- 
 strictor of the larynx; 5 — Arytenoideus. Attachments : 
 Median raphe and the superior part of the external face 
 of the arytenoid ; it constricts the larynx. 
 
 Mucous membrane covered with stratified tessalated 
 epitelium on the epiglottis and the vocal cords, ciliated 
 
100 EQUINE ANATOMY. 
 
 elsewhere. Blood vessels : laryngeal arteries. ]N^erves : 
 the superior and inferior laryngeal, furnished by the 
 pnenmo-gastric. 
 
 The external surface of the larynx offers four planes : 
 a superior, inferior and two laterals. 
 
 The internal surface offers three regions: a middle, 
 the glottis; a superior, the supra-glottis, and an infe- 
 rior, the sub-glottis. Tlie first is comprised between 
 the vocal cords; the second shows the two ventricles 
 of tlie larynx, the sub-epiglottic sinus and the entrance 
 of the larynx ; the third exhibits the posterior border 
 of the vocal cords and the sub-arytenoid sinus. 
 
 Salivary glands.— 1. Parotid. Division: Two faces, 
 two borders and two extremities. External face shows 
 a longitudinal groove for the jugular vein, and is cov- 
 ered by the parotido auricularis muscle. Internal face 
 covers the guttural pouch, the insertion of the small 
 oblique muscle of the head and mastoido humeralis, 
 occipito-hyoideus, styloid bone, digastricus, sterno-max- 
 illaris, maxillary gland, external carotid artery and 
 facial nerve. Anterior border rests on the teraporo- 
 maxlllary joint, subzygomatic vessels and nerves and 
 maxillo-muscular vessels. Posterior border is separated 
 from the wing of the atlas by the levator humeri. 
 Superior extremity embraces concha. Inferior extrem- 
 ity is comprised in the angle formed by the jugular 
 
HEAD. 101 
 
 and glosso-facial veins. Blood vessels : small arteri- 
 oles. I^erves : facial, inferior maxillary and carotid 
 plexuses. 
 
 Duct of S tenon lays on tendon of the sterno-max- 
 illaris, enters the intermaxillary space, alongside the 
 internal masseter, above the glosso-facial vein ; reaches 
 the maxillary lissure ; runs up in front of the anterior 
 border of the external masseter, obliquely forward 
 under the glosso-facial vein and artery ; passes through 
 the cheek to open opposite the third upper molar. 
 
 2. Maxillary or sub-maxillary. — Division : Two 
 faces, two borders and two extremities. External face 
 corresponds to the internal pterygoideus, the digastri- 
 cns, the sterno-m axillaris and the cellulo aponeurosis, 
 which separates it from the parotid. Internal face 
 applied to the side of the larynx, the guttural pouch, 
 the carotid artery and nerves accompanying it. Supe- 
 rior border margined by the digastricus. Inferior bor- 
 der is in contact with the glosso-facial vein. Posterior 
 extremity rests on the wing of the atlas. Anterior ex- 
 tremity is between the pterygoideus internus and the 
 hyo-thyroideus muscles. Vessels : innominate branches. 
 Is erves : from the carotid plexus. 
 
 Duct of Wharton runs from between the mylo-hyoid- 
 eus and great hyo-glossus, crossing outwards the glosso- 
 facial artery and great hypo-glossal nerve, inwardly, 
 
102 EQUINE ANATOMY. 
 
 the digastricus and the lingual nerve, passes between 
 the stjlo-glossus and the sub lingual gland, to end in 
 front of the frsenum of the tono-ue. 
 
 3. Sublingual. — Division : Two faces, two borders, 
 and two extremities. External face covered by the 
 mylo-hyoideus. Internal face rests on the duct of 
 Wharton, the stylo and genio-glossus muscles. Su- 
 perior border forms the lingual crest. Inferior border 
 lays between the mylo-hyoideus and the genio-glossus 
 muscles. Posterior extremity receives the lingual 
 nerve. Anterior extremity runs to the angle of the 
 inferior maxillary bone. 
 
 Duct:8 of Rivinus, fifteen or twenty open on the 
 
 11" , ■ II '_ - - Mil - II — I — fr — -' -*- 
 
 lingual crest. Blood vessels, sublingual artery. 
 ^Nerves, lingual and carotid plexus. 
 
 4. Molar. — Superior, along the superior border; 
 and inferior along the inferior border of the buccinator. 
 
 5. Labial, lingual, staphtline or palatine, in the 
 lips, tongue and velum palati. 
 
 AXGEIOLOGY. 
 
 Arteries. — The three terminal branches of the prim- 
 itive, or common carotid : 1 — occipital : 2 — internal ; 
 ■3 — external carotid. ■ 
 
 a. Occipital artery runs under the transverse pro- 
 'Cess of the atlas, behind the guttural pouch, between 
 
HEAD. 
 
 loa 
 
 the maxillary gland and the anterior straight muscle 
 of the head, reaches the anterior foramen of the atlas^ 
 runs through it into the fissure of the external surface 
 and terminates by the occipito-muscular and cerebro- 
 spinal arteries. Its collateral branches are : 
 
 1. Prevertebkal. — Terminating by muscular and 
 meningeal branches. 
 
 2. Mastoid. — Going to the parieto-temporal canal 
 to anastomose with the spheno-spinal. 
 
 3. Atloido muscular. — Running backwards and 
 throus:h the atlas to anastomose with the verte- 
 bral. 
 
 Terminal branches : Occipito muscular. — Termin- 
 ating by asceTrdrng and descending branches, the last 
 anastomosing with the superior cervical. 
 
 Cerebro-spinal. — Penetrates the antero-internal 
 foramen of the atlas, enters the vertebral canal, and 
 terminates by two branches — one forming the basilar 
 trunk, the other the median spinal. 
 
 Basilar trunk. — Situated on the inferior face of 
 the bulb and pons Varolii, and dividing into two 
 branches wliich give off the posterior cerebral artery. 
 It sends collateral branches to the bulb and pons Var- 
 olii, the posterior arr^s4l^r"Ki^ Ts^'efegllar arteries and 
 two^lwasciie^-tothe-mt^'ntrl cai*odT4-. 
 
 PosTERioRs^ERKBR54* tBr»inate"Tit€ 'Bltsiiar^'btfmfev 
 
104 EQUINE ANATOMY. 
 
 Tli^are given off behind the maxilla^r tub^cle ^an-d 
 receive the posterior communicating arterjN 
 
 Median spinal follows the spinal marrow, back- 
 wards to its end, being supplied by branches from the 
 vertebral, intercostal, lumbar and lateral sacral. 
 
 h. Internal carotid. — Ascends beneath the cra- 
 nium to the foramen lacerum, reaching through the 
 carotid fossa of the external surface of the sphenoid, 
 the carotid notch of the superior border, and then 
 into the cranium by a double flexure, terminates by 
 ^ke^pofete^r eo m - mii tTTcati ttg artery, which ana.yl;omQac.* 
 -wrri^ the posterior cerebral, and by a&ot - h e r branoh 
 w hich furnichca the middle and anterior cerebral. 
 
 c. External carotid. — Continuation of the prim- 
 itive carotid, runs forward to the posterior border 
 of the long branch of the hyoid bone, passes between 
 it and the stylo-hyoideus, bends upward, and near the 
 neck of the maxillary bone divides into its terminal 
 branches — the superficial temporal and internal maxil- 
 larj. Its collateral branches are the glosso-facial, the 
 maxillo-muscular and posterior auricular. 
 
 1. Glosso- facial. — Rises from the external carotid 
 as it passes beneath the stylo-hyoideus, turns down- 
 wards on the side of the pharynx in the intermaxillary 
 space, enters the maxillary groove, becomes superficial 
 on the anterior border of the masseter muscle, to the 
 
HEAD. 105 
 
 lateral surface of the face, and divides into ascending 
 and descending branches ramifying in the muscles of 
 that region. Its collateral branches are : 1 — Pharyn- 
 geal, terminating in the velum palati and the walls of 
 the pharynx; 2 — Lingual, goes to the tongue in its 
 upper portion, anastomosing in front with that of the 
 opposite side, forming a large arch ; 3 — Sublingual, 
 supplies lower part of the tongue and the buccal mu- 
 cous membrane; 4 — Inferior coronary, supplies the 
 lower lip and muscles of the inferior part of the lat- 
 eral surface of the face ; 5 — Superior coronary, goes 
 to the upper lip, where it anastomoses with the 
 palate. 
 
 2. Maxillo-muscular. — Passes between the parotid 
 gland and the posterior labial border of the maxillary 
 bone, where it divides into an external superficial and 
 an internal deep, branches going to the masseter 
 muscles. 
 
 3. Posterior auricular. — Passes upwards under the 
 parotid to the base of the concha, passing on its pos- 
 terior face to the superior extremity, sending off a few 
 glandular and muscular branches. , 
 
 Superficial temporal — Pas^'''*trp^rds' between 
 the parotid, guttural pouch and the condyle of the max- 
 illary bone, to terminate in the anterior auricular ancj 
 8ub-zygomatic trunk. 
 
106 EQUINE ANATOMY. 
 
 Anterior auricular. — -liunning behind the temporo- 
 maxillary joint beneath the parotid, to reach the cro- 
 taphite muscle, and after giving glandular, auricu- 
 lar and mus(;ulai: branches tern>inate&r/; — J ^ 
 
 SuB-zYGOMATic. — 1 asscs outwards between the an- 
 terior border of the parotid and the posterior border 
 of the maxillary bone with the facial nerve, and divides 
 into the transversal artery of the face, which rims hor- 
 izontally on the superior border of the external masse- 
 ter and ramifies in it, and into the masseteric, going to 
 the same muscle. , • _ , >^ -^^ fe, , , ^uoAAytUy 
 
 Internal maxillary. — Running to tlie subsphenoi- 
 dal canal, it passes through to the orbital hiatus and 
 arriving at the maxillary opening dips into the pala- 
 tine canal as the palato-labial. Collateral branches : 
 1 — inferior dental, traverses the inferior maxillo 
 dental canal to end at the mental foramen in two small 
 twigs, one external anastomosing with the inferior 
 coronary, one deep to the roots of the incisive teeth 
 and tusk. It sends collateral branches to the molar 
 teeth and muscles of the masseteric regions ; 2 — ptery- 
 goid, going to the pterygoid and peristaphileus muBcles ; 
 
 3 tympanic, 'to the tympanum with branches to the 
 
 guttural pouches; 4 — spheno-spinal, enters the temporo- 
 parietal canal to anastomose with the mastoid artery 
 /C^lLdlSp^ the occipital ; 5 — posterior deep temporal, to the 
 
HEAD. 
 
 107 
 
 crotapliite muscle in the temporal fossa ; 6 — anterior 
 deep temporal, in the crotaphite also, and the adipose 
 tissue of the fossa; 7 — ophthalmic, from the ocular 
 sheath, return into the cranium through the orbital 
 foramen, and divides into meningeal and nasal branches. 
 The orbital portion gives off muscular branches, cen- 
 tral artery of the„ reiinat ciliary, supra orbital and 
 lachrymal ; the cranial portion, the cerebral branches ; 
 8 — buccal, supplies the molar glands, the buccinator 
 and the maxillo-labialis rnuscles; 9 — staphyline, to the 
 velum palati ; 10 — superior dental, goes to the supe- 
 rior raaxillo-dental canal, and distributed like the infe- 
 rior dental; 11 — nasal, runs through the nasal foramen 
 into the nasal fossa, where it ends by external and 
 internal branches, ^j ^ ' " '^z; 
 
 Palato-labial, passesrrom the inaxfflai^ hiatus to ^ 
 tlie palatine canal, through it to the front part of the 
 palate, to the incisive foramen where it anastamoses 
 with the opposite one, forming a single trunk, which, 
 passing through the incisive foramen, reaches the upper 
 lip and terminates by anastamoses witli the superior 
 coronary. 
 
 Veins. — Three principal trunks : superficial temporal, 
 internal maxillary and sinuses of the encephalic dura 
 mater ; they form the root of the jugular. 
 
 1. Superficial temporal. — Satellite of the temporal 
 
108 EQUINE ANATOMY, 
 
 arterial trank with two principal roots, the anterior 
 auricular and the sub -zygomatic. 
 
 2. Internal maxillary. — Supplied by the buccal 
 vein. It receives numerous collateral branches, viz : 
 the lingual, inferior dental, a deep temporal trunk and 
 a pterygoid. 
 
 3. Cephalic sinuses of the dura mater. — Four 
 principal : the sinuses of the falx cerebri, the cavern- 
 ous or sphenoidal, the occipito-atloid and the rudiment- 
 ary sinuses, divided into lateral and inferior median. 
 These sinuses are supplied from the dura mater or from 
 nervous substance ; some of the last are superficial, 
 the others, internal, are provided by the great vein of 
 the brain or vena G-aleni. All the sinuses collect through 
 the means of the parieto-temporal and subsphenoidal 
 confluents, and empty into the temporal, pterygoid and 
 occipital veins. 
 
 Other veins of the head considered as affluents of 
 the jugular, are : 1 — the maxillo-muscular ; 2 — the 
 posterior auricular ; 3 — the occipital ; 4 — the external 
 maxillary or glosso-facial, formed by the angular of 
 the eye and another small branch, by the alveolar, 
 labial or coronary, buccal and sublingual as collateral 
 branches. 
 
 LymphaticSi— Two groups: 1 — The pharyngeal, sit- 
 uated on the lateral sides of the pharynx below the 
 
HEAD. 109 
 
 guttural poncli, and receiving all the lympliatics of the 
 head ; 2 — Tlie submaxillary, situated in the intermax- 
 illary space, and receiving the lymphatics of the tongue, 
 cheeks, lips, nostrils and nasal fossae. 
 
 IVEUROLOGY. 
 
 Twelve pair of cranial nerves. 
 
 1. Olfactory. — Formed by the olfactory lobe, 
 which has the appearance of a ganglion, grey inferiorly, 
 and white superiorly. It rises by two roots of white 
 substance, which unites into one band, and is situated 
 in the ethmoidal fossa, where through the foramina of 
 the cribriform plate of the ethmoid, it sends the true 
 nerves. The olfactory lobes are hollowed, and com- 
 municate with the cavity of the lateral ventricules. 
 The nerves, varying in number, ramify in the mu- 
 cous membrane of the septum nasi and ethmoidal vol- 
 utes. They are the special nerves of the organs of 
 smell. 
 
 2. Optic. — E.ise on the external side of tlie thalami 
 optici by white bands, and from the corpora quadri- 
 gemina. Course : Pass in front of the cerebral pedun- 
 cles, arrive at the inferior face of the brain, form the 
 chiasma, reach the optic duct, and perforate the ocular 
 envelope at the bottom of the ocular globe, and enter 
 
110 EQUINE ANATOMY. 
 
 the eye as the retina. They are exclusive to the sense 
 of sight. , ^ 
 
 3. Common oculo motor. — Emanates from the cere- 
 bral peduncles near the peduncular fissure by eight 
 branches. Course : The single trunk of the nerve runs 
 outwards to the smallest supra sphenoidal canal, passes 
 through the orbital liiatus, and ramifies in the muscles 
 of the eye, except the external and posterior recti and 
 the great obliqiie. Functions : Essentially motor. 
 
 4. Fathetic^rinternal oculo motor. — Kises from 
 the band of E,eil behind the corpora quadrigemina by 
 two roots. Its course is outwards, downwards and for- 
 wards to reach the smallest of the susphenoidal canak, 
 penetrate the- outer sheath and ramify in the great 
 oblique muscle of the eye. Functions : Motor. 
 
 5. Trigemini or trifacial. — Is a mixed nerve, hav- 
 ing an external root, sensitive, and an internal, motor. 
 
 Sensitive root. — The largest comes from the an- 
 nular protuberance ; it runs forward and downwards 
 to the occipito-spheno-temporal hiatus, and terminates 
 in the Gasserian ganglion. This ganglion is crescent 
 shape, and situated in the cartilaginous substance 
 which closes the foramen lacerum ; it gives origin to 
 two branches, one passes out of the cranium, the other 
 is lodged in the external fissure of the cranial face of 
 the sphenoid and bifurcates; thus at its origin is divided 
 
HEAD. Ill 
 
 into three branches, the ophthahnic and superior naaxil- 
 lary nerves, the inferior maxillary nerve. 
 
 Motor root. — Runs forward from the pons Yarolii 
 under the inferior face of the ganglion of Gasser, and 
 soon mingles with the inferior maxillary branch of the 
 sensitive root. 
 
 a. Ophthalmic. — Course : Enters the susphenoidal 
 canal with the third and fourth pairs, and in it divides 
 into the frontal, lachrymal and nasal or palpebro-nasal 
 nerves ; the frontal going to the orbital foramen, the 
 lachrymal ramifying in tlie lachrymal ghmd, the nasal 
 reenters the cranium with the ophthalmic artery, runs 
 through the plate of the ethmoid into the nasal fossa, 
 where it divides. 
 
 h. Superior maxillary. — Origin : Internal and su- 
 perior portion of the Gasserian ganglion. Course : 
 Placed in a groove on the internal face of the sphe- 
 noid, soon reaches the largest sphenoidal canal, runs 
 to the orbital hiatus, passes through the supra-maxillo- 
 dental canal, where it dips and runs as far as the lateral 
 surface of the face, where it terminates by suborbital 
 branches. Collateral branches : The orbital to some 
 muscles of the eye ; the great or anterior palatine to 
 the palatine groove and to the palate ; the staphyline 
 or posterior palatine to the velum palati ; the nasal or 
 spheno-palatine to the pituitary membrane; the dental 
 
112 EQUINE ANATOMY. 
 
 to the teeth of the superior jaw. Termmal branches : 
 The suborbital to the skin and muscles of the nostrils 
 and upper lip. 
 
 c. Inferior maxillary. — Course : leaving the cra- 
 nium, it passes inside the temporo-maxillary joint, runs 
 forwards and downwards towards the maxillo-dental 
 canal, through which it passes and comes out at the 
 mental foramen and terminates in the mental nerves. 
 Collateral branches : 1 — the masseterine, to the mas- 
 seter muscle after giving off the posterior deep and 
 middle deep temporal ; 2 — the buccal, for the lateral 
 face of the cheek after furnisliing the anterior deep 
 temporal ; 3 — the nerve of the internal pterygoid 
 muscle ; 4 — the superficial temporal or sub-zjgomatic, 
 which anastamoses with the facial ; 5 — the lingual, to 
 the tongue ; 6 — the nerve of the mylo-hyoideus mus- 
 cle ; 7 — dental branches to the teeth of the inferior 
 jaw. Terminal branches to the inferior lip united 
 with a branch of the facial nerve. 
 
 6. External oculo-motor. — Origin : on the rachi- 
 dian bulb behind the annular protuberance. Course : 
 runs through the sphenoidal canal to the orbit, ramify- 
 ing in the external rectus of the eye. 
 
 7. Facial. — Motor at its origin, it becomes mixed 
 afterwards. Origin : from the bulb immediately be- 
 hind the pons Varolii. Course : outwards, takes the 
 
HEAD. 113 
 
 iaternal auditory hiatus to the aqueduct of Fallopius, 
 through the stjlo-mastoid foramen, then under the 
 parotid, to the posterior border of the maxillary bone, 
 on the external face of the masseter and terminates by 
 the zygomatic plexus. Collateral branches : 1 and 
 2 — the great and small superficial petrosal nerve ; 3 — 
 the nerve of the muscle of the stirrup ; 4: — the nerve 
 of the corda tympanii, all to the internal ear ; 5 — an 
 anastomotic branch to the pneumogastric ; 6 — the 
 nerve of the stylo-hyoideus muscle ; 7 — of the digas- 
 tricus ; 8 — of the great kerato-hyoideus ; 9 — a cervical 
 branch ; 10 — nerves to the guttural pouches and to 
 the parotid gland ; 11 — the three auricular nerves, 
 posterior, middle and anterior. Terminal branches 
 form the sub-zygomatic plexus, over the external sur- 
 face of the masseter muscle and ramifying in the tissue 
 of the cheeks, lips and nostrils. 
 
 8. Auditory or acoustic. — Origin : From the bulb 
 by two branches, one from the restiform bodies, the 
 other from the floor of the fourth ventricle. Course : 
 Passes behind the seventh into the internal auditory 
 hiatus, and divide in two branches, anterior and pos- 
 terior, ramifying into the cochlea, the vestibulum and 
 semicircular canals. 
 
 9. Glosso pharyngeal. — Origin: On the side of 
 the bulb between tlie restiform bodies and the lateral 
 
114 EQUINE ANATOMY. 
 
 fasciculus of the bulb, by eight or ten roots, uniting to 
 forjn the petrous ganglion. Course : Downwards with 
 a curve concave forward, behind the great branch of 
 the hyoid bone, between the guttural pouches and mas- 
 seter muscle, runs alongside the hyoid bone and reaches 
 the base of the tongue, where it terminates. Collateral 
 branches : 1 — The nerve of Jacobson, giving off the 
 great and small deep petrosal ; 2 — Branches to the 
 superior cervical ganglion ; 3 — Branch to the cartiod 
 plexus ; 4 — a pharyngeal nerve to the superior wall 
 of the pharynx. 
 
 10. — Fneumogastric or par vagum. — Origin: Two 
 roots: the sensitive from the grey mass near the floor 
 of the fourth ventricle behind the glosso-pharyngeal, 
 then passes out of the cranium to the jugular ganglion ; 
 the motor root rises more posteriorly from the middle 
 of the respiratory track, runs also outwards and goes 
 to the jugular ganglion, which is elongated, flattened 
 from above below and imbedded in the cartilaginous 
 mass closing the foramen lacerum. Course : After its 
 ■connection with the ganglion, the mass is united to the 
 spinal, but soon separates from it, leaves the glosso- 
 pharyngeal pass between them alongside and behind 
 the guttural pouches, crosses the occipital artery, unites 
 with the cervical portion of tlie great sympathetic, 
 passes into tlie tliorax, and then separates from this 
 
HEAD. 115- 
 
 last nerve. In the chest the right nerve turns obliquely 
 round the axillary artery to place itself outside the 
 trachea until the root of the bronchia, where it ends ; 
 the left nerve remains attached to the artery, crosses 
 outv^ards the origin of the aorta, and terminates by 
 branches which give rise to the bronchial plexus and 
 oesophageal nerves. Collateral branches : 1 — Branches 
 to the superior cervical ganglion ; 2 — The pharyngeal 
 to the superior face of the pharynx; 3 — The superior 
 laryngeal to the susglottic portion of the larynx ; 4 — 
 Branches to inferior cervical ganglion ; 5 — Inferior 
 laryngeal or recurrent nerves, which rise from the tenth 
 into the thoracic cavity, and run forwards and upwards 
 into the larynx, where they divide into the muscles and 
 mucous membrane of the subglottic portion. Terminal 
 branches : Bronchial plexus going to the mucous mem- 
 brane of the bronchia ; oesophageal, divided into supe- 
 rior and inferior, the last terminating in the walls of 
 the stomach ; the former into the left sac of that organ, 
 and the solar plexus. 
 
 II. Spinal OR ACCESsoRius. — Origin: from the cer- 
 vical marrow, runs upwards and forwards in the verte- 
 bral canal till it reaches the tenth pair, with which it 
 comes out of the cranium. Course : first united to 
 the par vagum, it soon leaves it, runs backwards, passes 
 under the maxillary gland, arrives at the posterior 
 
116 EQUINE ANATOMY. 
 
 border of the levator humeri ; downwards to the front 
 of the shoulder, then turns upwards under the cervical 
 trapezium muscle and terminates in the dorsal portion 
 of the same; while it gives several muscular branches, 
 it receives some from the first, second, tliird, fourth 
 and fifth, and sometimes sixth, cervical pairs. 
 
 12. Gkeat hypoglossus. — Origin: from the inferior 
 face of the bulb, by twelve roots, which run through 
 the dura mater by two or three fasciculi and then 
 unite into one trunk. Course : after first communi- 
 cating with the first cervical pair, it passes between the 
 tenth and eleventh cranial pairs, runs downwards 
 alongside the guttural pouches, communicates with 
 the superior cervical ganglion, goes outside the exter- 
 nal carotid on the side of the pharynx and larynx, dips 
 between the mylo-hyoideus and basio-glossus and ter- 
 minates in the tongue. 
 
 Sympathetic IVerve— Cephalic portion is composed 
 of three ganglions : the ophtlialmic, resting on the 
 common oculo-motor nerve, is very small ; the spheno- 
 palatine or ganglion of Meckel, varying in disposition, 
 generally found under the superior maxillary nerve, it 
 is the largest of the three ; the otic or ganglion of 
 Arnold, not always present ; when it exists, it is inside 
 the origin of tlie inferior maxillary nerve. 
 
CHAPTER V. 
 
 T RU isr K. 
 
 Supporting the head at the anterior extremity and 
 terminating posteriorly by the tall ; it has for base, od 
 the median line a series of bones called vertebrae, and 
 is composed of three cavities; the thoracic; the ab- 
 dondnalj separated by the diaphragm muscle ; and the 
 pelvic cavity, a dependance of the abdominal. 
 
 Vertebrie — General characters. — They are single 
 bones perforated by the vertebral foramen, which in the 
 series forms the vertebral canal. Division : A body 
 and annular portion. TJie body has two faces : one 
 superior with two triangular surfaces and two grooves« 
 for venous sinuses ; the inferior with a crest sometimes 
 called the inferior spinous process. It has two ex- 
 tremities : an anterior with a round head more or less 
 prominent, one posterior with a cavity for the reception* 
 of the head. The antudaafcportion has an internal 
 surface, concave and forrifetg the vertebral foramen '; 
 
118 EQUINE ANATOMY. 
 
 and ail external, presenting the superior spinous pro- 
 cess and two transverse processes. In front and be- 
 hind are found two articular facets, and at their base 
 notches for the formation of the foramina of conjuga- 
 tion. Development : two principal and five secondary 
 centers. 
 
 In the vertebral canal is found the spinal makkow. 
 It is covered by the three membranous envelopes, dura 
 mater, arachnoid and pia mater. It is a thick, white, 
 hollow mass, continuation of the medulla oblongata, 
 and ending in a point at the anterior third of the sacral 
 canal. Weighing about ten ounces, it is slightly de- 
 pressed from above below, and presents a brachial and 
 lumbar enlargements or bulbs where the nerves of the 
 fore and hind extremities are given off. Its external 
 surface shows on the superior and inferior face a deep 
 fissure, and on each side of these, two others scarcely 
 noticeable. Its internal structure shows that it is hol- 
 low, and presents in its middle a mass of grey matter 
 surrounded by white substance. They are so arranged 
 that the superior and inferior fissures of the external 
 surface are separated by a white and a grey commis- 
 sure, the last tending upwards and downwards towards 
 the surfaces of the organ prolongations or cornua. The 
 medulla receives blood from arteries of the pia mater, 
 and branches of the median spinal artery. 
 
CHAPTER YL 
 
 IS^ E C K . 
 
 OSTEOLOGY. 
 
 Seven cervical vertebrae. 
 
 General characters: They are the longest and thick- 
 est of all ; the inferior spinous process of the body is 
 well developed ; the head well detached ; the cavity 
 very deep and larger than the head it receives ; the 
 superior spinous process is a rough crest ; the trans- 
 verse processes are very large, bending downwards and 
 perforated at their base by the trachelian foramen ; 
 the articular facets are plano-convex and very wide ; 
 the foramen of conjugation very large. 
 
 Specific characters : Firsts or atlas is very large and 
 more flat ; the body is quite small ; its inferior spinous 
 process is replaced by a tubercle ; its superior face is 
 divided into a surface for ligamentous attachment, and 
 an articular surface ; it has no head nor cavity behind ; 
 in their stead are found forward two deep cavities 
 formed by four concave facets for articulation with 
 
120 EQUINE ANATOMY. 
 
 tlie occipital ; beliind are two piano convex facets for 
 articulation with the axis ; it has no superior spinous 
 process, but a rough surface ; its transverse processes 
 are very wide and have three foramina. Development : 
 six nuclei of ossification. 
 
 Second^ or axis. — The longest of all ; has no head but 
 the odontoid process ; the inferior spinous process is 
 fiharp ; the superior thick and bifid behind ; the trans- 
 verse process is sharp and has a single tubercle ; it 
 iias no articular facets forward, and shows a deep 
 notch sometimes a foramen in front of the body. 
 
 Third. The space between the anterior and posterior 
 articular processes is deep. 
 
 Fourth. These are then united by a thin edge. 
 
 Fifth. There by a rough, thick crest. In all three 
 the transverse processes are bitubercular. 
 
 Sixth. Transverse processes tritubercular. 
 
 Seventh, or prominent has a superior spinous process 
 VQvy high, no inferior one, a concave facet on the 
 border of tlie posterior cavity ; the transverse processes 
 are unitubercular ; no trachelian foramen ; the vertebral 
 canal is very large. 
 
 SYIVDESMOLOGY. 
 
 General articulations. — That of body : Amphiar- 
 thosis. Articular surfaces : Head and cavity of the 
 
NECK. 121 
 
 body. Means of union : Fibro-cartilnge and a supe- 
 rior and inferior common v^ertebral liii'Mment. 
 
 That of tlie annular part : Double artlirodia. Artic- 
 ular surfaces : Articular facets. Means of union : Inter- 
 spinal ligament, inter annular ligament, two capsular, 
 superior spinal ligament (cervical portion) or ligamen- 
 tum nuclise, composed of a funicular cord and two 
 median sheets of yellow elastic tissue. Motion : Sliding. 
 
 Special articulations — Atloido-occipital : Condy- 
 loid. Articular surfaces : Two condyles of tlie occipi- 
 tal, two cavities in front of the atlas. Ligaments : One 
 capsular with four reinforcing bands. Two synovial cap- 
 sulse, one for each condyle and cavity. Motion : Flex- 
 ion, extension, lateral inclination and circumduction. 
 
 AxoiDO-ATLOiD. — Troclioid or lateral ginglymus. Ar- 
 ticular surfaces : A groove on tlie superior face of the 
 body of tlie atlas, and two facets on each side of it, the 
 inferior face of the odontoid process of the axis and the 
 two facets laterally. Ligaments : Superior and inferior 
 atloido-axoid ligaments, odontoid ligament, one capsu- 
 lar. One synovial capsnla. Motion: Rotation. 
 
 MYOLOGY. 
 
 Superior region : Seventeen muscles. 
 1. Cervical trapezium. — (See dorsal region, de- 
 scribed as cervical portion of t^e trapezium.) 
 
 /^tUU^. 
 
v^ 
 
 122 EQUINE ANATOMY. 
 
 2. IIhom:boideus. — Synonyms. Kliomboidens longns 
 and brevis, (P). Ccrvico-subscapularis, (G). Dorso- 
 scapularis, (L). Attachments : The funicular portion 
 of the cervical ligament, tlie apex of the spinous pro- 
 cesses of the second, third, fourtli, fifth or sixth dorsal 
 vertebrae, the internal face of the cartilage of the scap- 
 ula. Action : Draws the shoulder upwards and for- 
 wards. 
 
 3. Anoularis scapula. — Synonyms. Trachelo-sub- 
 scapularis, (G). Anterior portion of the serratus 
 magnus, (P). Attachments : The transverse processes 
 of the five last cervical vertebrse, the anterior triangu- 
 lar surface of the internal face of the scapula. Action : 
 Pulls the scapula forward, may assist in the lateral 
 inclination of the neck. 
 
 4. Splenius. — Synonyms. Cervico-trachelian, (G). 
 Attachments: The ligamentum nuchse, the summit of 
 the spinous processes of the first dorsal vertebrae, the 
 mastoid crest of the occipital, the transverse processes 
 of the atlas, and that of the third, fourth and fifth cer- 
 vical vertebrfB. Action : Extensor of head and neck. 
 
 5. Great complexus. — Synonyms. Dorso-occipi 
 talis, (G). Complexus major, (P). Attachments : 
 The summit of the spinous processes of the first dorsal 
 vertebrse, the transverse processes of the two first dor- 
 sal, the articular tubercles of the cervical vertebrae, 
 
NKCK. 123 
 
 tlie posterior face of the occipitfil protuberance, on 
 eacli side of the cervical tuberosity. Action : Extensor 
 of the head. 
 
 6. Small complexus. — Synonyms. Dorso-niastoid- 
 ens, (G). Traclielo-mastoidens, (P). Attachments • 
 The transverse processes of the two first dorsal verte- 
 brae, the articular tubercles of tlie cervical vertebrae, 
 the mastoid process of the temporal, the transverse 
 process of the atlas. Action: Extensor of the head, 
 which is carried sideways. 
 
 7. Transverse spinous of the neck. — Synonyms. 
 Dorso-spinalis, (G). Spinalis colli, (P). Attachments ; 
 On the five last articular tubercles of the cervical ver- 
 tebrae, the superior spinous processes of the sixth, fifth, 
 fourth, third and second cervical vertebrae. Action: 
 Extensor and inclinator of the neck. 
 
 8. Six intertransyeesal of the neck. — Synonyms. 
 Inter-cervical, (G). Not described by P. Attach- 
 ments : Upon the transverse and articular processes of 
 the cervical vertebrae, except the first. Action : Incline 
 the neck on one side. 
 
 9. Great oblique OF THE HEAD. — Synonyms. Axoido- 
 atloideus, (G). Obliquus capitis inferior, (P). At- 
 tachments : The spinous process of the axis, the trans- 
 verse process of the atlas. Action : Kotator of the 
 atlas and head. 
 
124 EQUINE ANATOMY. 
 
 10. Small oblique of the head. — Synonyms. At- 
 loido-mastoideus, (G). Obliquus capitis superior, (P). 
 Lateral atloido-oecipitalis, (L). Attacliments : To the 
 styloid process and external face ,of the occipital bone, 
 near and on the mastoid crest. Action : Inclines and 
 -extends the head. 
 
 11. Posterior gkeat steaight of the head. — Syn- 
 onyms. Long and short axoido-occipitalis, (G). Kec- 
 tns capitis posticus major and complexes minor, (P). 
 Attachments : Spinous process of the axis, on tlie oc- 
 cipital bone. Action : Extensor of the head. 
 
 12. Posterior small straight of the head. — Syn- 
 onyms. Atloido-occipitalis, (G). Rectus capitis posti- 
 cus minor, (P). Atloido-occipitalis superior, (L). At- 
 tachments : The superior face of the atlas, external 
 face of the occipital. Action : Extensor of the head. 
 
 Inferior region.— Eleven muscles. 
 
 1. Subcutaneous of the neck. — Synonyms. Por- 
 tion of the panniculus carnosus, (P). Attachments : 
 Trachelian cartilage of the sternum, the lateral surfaces 
 of the superior cervical muscles, the zygomatic crest. 
 Action ; Braces tlie muscles of the neck and pulls the 
 commissure of the lips backwards. 
 
 2. Mastoido-humeralis. — Synonyms, Levator hu- 
 meri, (P). Attachments: The mastoid process and 
 crest, the humerus, tlie transverse processes of the 
 
NECK. 125 
 
 four first cervical vertebrae. Action : Carries tlie an- 
 terior leg forward or inclines the head and neck to one 
 side. 
 
 3. Sterno-m AXILLARIS. — Attachments : The anterior 
 extremit}^ of the sternum, the posterior border of the 
 maxillary. Action : Flexes the head directly or to 
 one side. 
 
 4. Stern 0-HY0IDEU8. 6. Sterno-thyroideus. — 
 Synonyms. Sterno-thyro-hyodens, (P). Attachments : 
 The anterior extremity of the sternnm, the body of 
 the iiyoid bone, the thyroid cartilage. Action : De- 
 pressors of the hyoid bone and of the larynx. 
 
 6. Omo or subscapulo-hyoideus — Synonyms. Sub- 
 scapnlo-hyoidens, (P). Attachments: On the inner 
 surface of the subscapularis muscle, body of hyoid 
 bone. Action : Depressors of the hyoid and larynx. 
 
 7. Great anterior straight of the head. — Syno- 
 nyms. Traehelo-snb-occipitalis, (L). Kectus capitis 
 anticus major, (P). Trachelo-occipitalis, (L). At- 
 tachments : The transverse processes of the third, 
 fourth and fifth cervical vertebrae, the sphenoid bone 
 and basilar process of the occipital. Action : Flexes 
 tlie head directly or to one side. 
 
 8. Small anterior straight of the head. — Syno- 
 nyms. Atloido-sub occipitalis, (G). Rectus capitis 
 a.iticus minor, (P). Atloido-occipitalis inferior, (L). 
 
126 EQUINE ANATOMY. 
 
 Attachments: The body of the atlas, the basilar pro 
 cess of the occipital. Action : Cooperates to flex tlio 
 head. 
 
 9. Small lateral straight. — Synonyms. Atloido- 
 styloideuSj (G). Obliqnus capitis anticus, (P). Attach- 
 ment : To the atlas, tlie styloid process of the occipital. 
 Action : Congener of the other straight muscles. 
 
 10. Scalenus — Synonyms. Costo-tracheleus, (G). 
 Attachments : The transverse processes of the four last 
 cervical vertebrae, the superior extremity, anterior bor- 
 der and external face of the first rib. Action : Flexes 
 the neck directly or to one side, or acts as an assistant 
 to respiration. 
 
 11. Long muscle of the neck. — Synonyms. Sub- 
 dorso-atloideus, (G). Longus colli. (P). Dorso-at- 
 loideus, (L). Attachments : The body of tiie first six 
 dorsal vertebrae, tlie transverse processes, and the in- 
 ferior spinous processes of tlie first six cervical verte- 
 brae, the tubercle of the inferior face of tlie atlas. 
 Action : Flexor of the neck and of the cervical verte- 
 brae individually. 
 
 SPLAMH^OLOGY. 
 
 Trachea. — Cartilaginous tube extending from tlie 
 larynx to the base of the heart, whore it divides into 
 the right and left bronchia. Form : Cylindroid, slightly 
 
NECK. 127 
 
 flattened from above below. Connections : In the neck^ 
 with the oesophagus, carotid arteries, pneumo-gastric,. 
 sympathetic and recurrent nerves ; in the thorax, 
 above to the longus colli and oesopliagus, below to the 
 bronchial trunks, the anterior aorta, anterior vena cava,, 
 cardiac and recurrent nerves, base of the heart ; on tlie 
 sides, to the inferior cervical ganglion of the symp- 
 athetic, to tlie vertebral, superior cervical and dorsal 
 arteries and to the antei'ior mediastinum ; on the right 
 to the vena az3^gos ; on the left, to tlie cross of the 
 aorta and the thoracic duct. Structure : It consists of 
 about fifty cartilaginous rings, united by inter-cartila- 
 ginous ligament, lined by a mucous membrane covered 
 by ciliated epithelium, containing muscular fibres, and 
 receiving blood vessels from the carotid and the bron- 
 chial trunks, nerves from the recurrent and sympathe- 
 tic. 
 
 Qilsophagiis. — Form : A long membranous tube con- 
 necting the pharynx with the stomach, it is placed 
 above and to the left of the trachea, passes into the 
 thorax over the base of the heart, to the right pillar of 
 the diaphragm, terminating at the stomach in the car- 
 diac opening. Connections : At its origin, is situated 
 between the guttural pouches and the larynx ; in the 
 neck, above between the trachea and the longus colli ; 
 on each side the carotid artery and its nerves ; below, 
 
128 EQUINE ANATOMY. 
 
 with the trachea, scalenus muscle, blood vessels and 
 nerves of the neck ; and on the left side with the jug- 
 ular vein ; in the tliorax with the inferior cervical gan- 
 glion and its branches ; the vertebral, superior cervical, 
 and dorsal arteries and veins, with the left bronchia, 
 aorta, lung, oesophageal arterj and nerves. Structure : 
 Two coats of muscular fibres, a mucous membrane with 
 longitudinal folds, oesophageal arteries and branches of 
 the pneumo-gastric nerve. 
 
 Thyroid Gland.— Composed of two ovoid lobes, one 
 on each side of the lirst two rings of the trachea, united 
 by a small band running in front of the trachea. Struc- 
 ture : A fibrous envelope, parenchymtous mass, branches 
 of the thyro-laryngeal and thyroid accessorius arteries 
 and nerves from the first and second cervical pairs. 
 
 AXGEJOLOGY. 
 
 Arteries. — Fsimitive carotid. — Branches of the 
 cephalic trunk : E-unning along the trachea to the gut- 
 tural pouches and the larynx, where it terminates in 
 the arteries of the head. (See page 102.) Collateral 
 brandies: Innominated to the oesophagus, the trachea 
 and the cervical muscles ; the thyro-laryngeal, whicli 
 runs downwards to the thyroid gland and sends branches 
 to the larynx, and the thyroid accessorius to the thyroid 
 body by its posterior extremity. 
 
NECK. 1 29 
 
 Veins. — The jugular, formed by the superiicial tem- 
 poral and the internal maxillary vein, runs downwards 
 
 and backwards in the inferior extremity of the neck, 
 and terminates with the axillary vein to the gulf of 
 the jugulars. In connection above with the parotid 
 gland, below with the subscapulo hyoideus, panniculus 
 carnosus, trachea and to the left side the oesophagus. 
 Lymphatics. — They come from the pharyngeal to 
 the prepectoral ganglion or directly to the* great lym- 
 phatic vein. 
 
 NEUROLOGY. 
 
 Eight cervical rachidian pairs. — The superior 
 roots go to the muscles of the superior cervical region 
 and the cervico and tempero-auricularis muscles ; the 
 inferior roots of the six first pairs anastomose and 
 form by their branches the superficial cervical plexus ; 
 they ramify upon the sides of the neck and the mus- 
 cles of the chest. The seventh and eighth unite to- 
 gether, and with the two first dorsal form the brachial 
 plexus. 
 
 Sympathetic — Superior cervical ganglion. — Elon- 
 gated and fusiform ; it runs along the internal carotid 
 artery in a fold of the guttural pouches in front of 
 the transverse process of the atlas, and in connection 
 with the ninth, tenth, eleventh and twelfth pairs of 
 
130 EQUlNJfi ANATOMY. 
 
 cranian nerves forming the guttural plexus. Afferent 
 branches come from the cranian nerves ; efferent 
 branches, to the internal carotid to form the cavernous 
 plexus; to the primitive carotid, to form the carotid 
 plexus ; to tlie fauces and the pharynx, forming the 
 pharyngeal plexus. Uniting cord, single without col- 
 lateral branches united intimately to the pneumogas- 
 trie, runs down with it and ends at the inferior cervi- 
 cal GANGLION. This ganglion, larger than the superior, 
 is situated on the inside of the scalenus muscle, is of 
 various forms, sometimes single or double forming the 
 middle inferior ganglion. Afferent branches come 
 from the cervical pairs ; efferent branches, form the 
 cardiac nerves (five in number), and in front of the 
 trachea the tracheal plexus. 
 
CHAPTER YIL 
 
 THORAX. 
 
 OSTEOLOGY. 
 
 Dorsal Vertebrae. — Genp:ral characters: Body 
 very short ; head wide and somewhat flattened ; cavi- 
 ty is not deep, two small concave articular surfaces on 
 each side ; superior spinous processes are very high and 
 inclined hackwards ; transverse processes are unituber- 
 cular with a flat diarthrodial facet; the articular 
 facets are situated at tlie base of the spinous process ; 
 the posterior notches are very deep. 
 
 Specific characters. — The vertical diameter in- 
 creases and the lateral diminishes from forward back- 
 wards, the articular surfaces of the body are wider and 
 flatter as they go backwards, the inferior spinous pro- 
 cess is well developed forward, disappears from the 
 sixth to the ninth, reappears and increases to the last, 
 the intervertebral cavities diminish from the first to 
 the last, the superior spinous processes increase to tlie 
 
132 EQUINE ANATOMY. 
 
 fifth, then diminish to the last ; their obliquity is less 
 pronounced as it is more posterior, the articular facets 
 are closer to the median line, going towards the tenth, 
 and increase to the last ; the transverse processes, as well 
 as the articular surfaces, diminish from forward back- 
 wards ; the last has no facets on the posterior border. 
 
 Ribs. — Elongated bones, eighteen on each side, leaving 
 between them the intercostal spaces, and being pro- 
 longed downwards by the costal cartilages. 
 
 General characters. — Division : A middle part 
 and two extremities. Middle part : External face has 
 a groove in front and muscular impressions above. 
 Internal face is concave and smooth. The anterior 
 border is concave and sharp, the posterior convex, thick 
 and with vasculo-nervous fissure. The superior ex- 
 tremity has a head formed of two convex facets, 
 separated by a groove and a tuberosity with a flat dia- 
 throdial facet. Tlie inferior extremity has a small 
 irregular cavdty. Development : three nuclei, one for 
 the head, one for the tuberosity, one for the balance 
 of the bone. 
 
 Specific characters. — Division : Eight sternal or 
 true ribs, ten asternal or false ribs ; their length in- 
 creases from the first to tlie ninth, then diminishes to 
 the last, their width increases from the first to the sixth, 
 then diminishes backwards, their curve is shorter and 
 
THORAX. 133 
 
 more marked as it is more posterior, the groove of 
 the external face becomes less marked as th& rib is 
 narrower. 
 
 First rib — Has no groove on the external face, no 
 fissure between the facets of the head, shows large 
 muscular impressions on the external face, and an ar- 
 ticular facet on the inferior extremity of the internal 
 face. 
 
 Last rib — Has no groove externally, the facet of 
 the tuberosity and the posterior facet of the head 
 are united. 
 
 Costal Cartilages.— Those of the eight first ribs rest 
 on the sternum by a facet after articulating above 
 with the inferior extremity of the rib. Those of the false 
 ribs are united with their corresponding ribs by their 
 inferior extremity, which terminates in a point, and 
 rests directly upon each other. 
 
 Sternum.— Situation: under the thorax. Division: 
 Three faces, three borders, two extremities. The su- 
 perior face is concave and triangular ; the lateral face 
 is divided into a superior portion which shows diar- 
 throdial cavities and an inferior portion for muscular 
 attachments. The lateral border separates the latter 
 from the superior face ; the inferior border is convex, 
 thin and resembles tlie keel of a ship. The anterior 
 extremity forms tlie trachelian prolongation ; the pos- 
 
134 EQUINE ANATOMY. 
 
 terior extremity forms the x^^phoid cartilage flattened 
 from above below. Structure : bony and cartilaginous. 
 Development : six nuclei, 
 
 SYIVDESmOLOOY. 
 
 Intervertebral joints. (See cervical region, page 
 120.) 
 
 Vertebro-costal. — Arthrodia. — Formed by the fa- 
 cets of the head of the ribs and the cavities on each 
 side of the body of two adjacent vertebrse. Ligaments : 
 interarticular and inferior peripheric. Two synovial 
 capsulse. Motion, sliding. 
 
 CosTO-TRANSVERSAL. — Arthrodia. — Articular sur- 
 faces. Facets on the tuberosity of the rib and trans- 
 verse process of the posterior vertebrse. Ligaments : 
 posterior and anterior transverse costal ; one synovial 
 capsula. Motion, sliding. 
 
 Chondro-costal. — Synarthrodial. Articular sur- 
 faces, inferior extremity of the rib and superior ex- 
 tremity of the cartilage. Ligament : the periosteum. 
 
 Chondro-sternal. — Arthrodia. Articular surfaces : 
 the inferior extremity of the true I'ibs and the cavities 
 of the sternum. Ligaments : superior and inferior 
 sterno-costal. One synovial capsula. 
 
 Chondro-chrondral. — Attached by some yellow 
 elastic ligament. 
 
THORAX. 135 
 
 MYOLOGY. 
 
 Spinal Region. — Seven pairs. 
 
 1. Trapezium. — Synonyms : Dorso and cervico-acro- 
 mialis, (G). Attachments : The funicular cord of the 
 cervical ligament, the apex of the superior spinous pro- 
 cess of the first dorsal vertebrae, the tuberosity of the 
 acromion and external surface of the scapular aponeu- 
 rosis. Action : Raises the shoulder and carries it for- 
 wards or backwards. 
 
 2. Greatdorsal — Synonyms: Dorso-humeralis, (G). 
 Latissimus dorsi, (P). Attachments : The apex of the 
 spinous process of all the lumbar and fourteen or fif- 
 teen last dorsal vertebrae, internal tuberosity of the hu- 
 merus. Action : Carries the arm backwards and up- 
 wards. 
 
 3. Small anterior serrated. — Synonyms : Dorso- 
 costalis, (G). Superficialis costarum, (P). Anterior 
 serrated, (L). Attachments: The summit of the spi- i 
 nous process of the tliirteen dorsal vertebrae follow- ! 
 ing the first, the external face of the anterior border of i 
 tlie nine ribs following the fourth. Action : Inspir- \ 
 atory. ' 
 
 4. Small posterior serrated. — Synonyms. Lumbo- 
 costalis, (G). Superficialis costarum, (P.) Posterior • 
 serrated, (L). Attachments : The spinous processes of \ 
 
136 EQUINE ANATOMY. 
 
 the last dorsal vertebrae from the tenth, the lumbar 
 vertebrae, posterior border and external face of the 
 nine last ribs. Action : Expiratory. 
 
 5. Ilio-spinalis. — Synonyms. Longissimus dorsi, 
 (P). Attachments : The lumbar border, external an- 
 gle and internal face of the ilium, sacro-iliac ligament, 
 sacrum, spinous processes of all the lumbar, dorsal, and 
 last four cervical vertebrae, articular facets of the 
 lumbar vertebrae, the transverse processes of all the 
 dorsal and last four cervical vertebrae, costiform pro- 
 cesses of the lumbar vertebrae, external surface of the 
 fifteen or sixteen last ribs. Action : Extensor of the 
 vertebral column ; may act as an expirator. 
 
 6. Common intercostal. — Synonyms. Trachelo- 
 costalis, (G). Transversal costarum, (P.) Attach- 
 ments : The external face of the ribs, transverse pro- 
 cess of the last cervical vertebrae. Action : Depresses 
 the ribs. 
 
 T. Transverse spinous of the back and loins. — 
 Synonyms. Transverso-spinous, (G). Spinalis and 
 semi-spinalis dorsi, (P). Attachments: The lateral 
 border of the sacrum, the articular processes of the 
 lumbar and transverse processes of the dorsal vertebrae, 
 spinous processes of the sacral, lumbar, dorsal and last 
 cervical vertebrae. Action : Extensor of the spine. 
 
 Costal Region.— Fifty-four pairs. 
 
THORAX. 137 
 
 1. Great serratus. — Synonyms. Costo-siibscapu- 
 laris, (G). Posterior portion of the serratus magniis, 
 (P). Attachments : The external face of the eight 
 true ribs, the anterior and posterior triangular surfaces 
 of the internal face of the scapula. Action : Suspen- 
 sor of the trunk, and may act as inspirator. 
 
 2. Transverse of the ribs. — Synonyms. Costo- 
 sternalis, (G). Lateralis sterni, (P). Attachments : 
 Sternum, fourth costal cartilage and external face of 
 the first rib. Action : Expiratory. 
 
 3. Seventeen external intercostals. — Attach- 
 ments : Posterior border of the preceding to external 
 face of succeeding rib. Action : Inspiratory. 
 
 4. Seventeen internal intercostals. — Attach- 
 ments : Anterior border of the posterior to posterior 
 border and internal face of the anterior rib. Action : 
 Expiratory. 
 
 5. Seventeen supercostals. — Synonyms. Trans- 
 verso-costalis, (G). Levatores costarum, (P). Attach- 
 ments: Trans\^erse processes of the dorsal vertebrae 
 and external face of the ribs. Action : Inspiratory. 
 
 6. Triangularis of the sternum. — Synonyms. Ster- 
 no-costalis, (G). Sterno-costalis, (P). Attachments : 
 Superior face of the sternum and internal face of the 
 cartilages of the true ribs except the first. Action : 
 Expiratory. 
 
138 EQUINE ANATOMY. 
 
 Muscular attachments of the anterior extremity 
 to tlie trunk. 
 
 Pectoral or Axillarj jpeg|on.--J. Superficial pec- 
 TORAL. — Synonyms, ^ ^e^t orfiho trftnoFcron s , (P). Divis- 
 ion : 1 — Sterno-li^eralis. Attachment^: Anterior ap- 
 pendix and inferior border of tlie sternum, anterior crest 
 of theh^Kfiery^^^Aotion : Adductor of the forearm. 
 2— SSrn^ap^^ii^oticus^ Attachments: Entire inferior 
 boroerof tlie sternum, anterior ridge of the humerusj 
 fascia of tlie external face of the anti-brachial aponeu- 
 rosis. Action : Adductor of the leg and tensor of the 
 aponeurosis. 
 
 2. Deep pectoral. — Division : 1 — Sterno-trochineus. 
 Synonyms. Fectoralis mao^n us, (P). Attachments: 
 Tunica abdominalis, two posterior thirds of the inferior 
 border of the sternum, internal tubercle of the superior 
 extremity of the humerus. Action : Draws the leg back- 
 wards. 2 — Sterno-prescapularis. Synonyms. Pectoralis 
 ^aiivns , (P). Attachments : On the side of the sternal 
 keel, the cartilages of the three or four first ribs, the 
 aponeurosis covering the antea-spinatus muscle, the 
 cervical angle of the scapula. Action : Draws the 
 shoulder backwards and downwards, and tensor of 
 the scapular aponeurosis. 
 
THOKAX. 139 
 
 SPLAXCHIVOLOGV. 
 
 Pleura. — Serous membriine lining tlie thoracic cavity, 
 forming two sacs resting on each otlier and the medi- 
 astinum. The anterior mediastinum is that portion sit- 
 uated in front of the heart ; tlie posterior is the one 
 posterior to tliat organ. The costal pleura lines the 
 internal face of the ribs; the diaphragmatic pleura lines 
 the anterior face of the diaphragm muscle. With the 
 mediastine pleura, they form the parietal layer of tliat 
 serous membrane. The pulmonary pleura covers the 
 external face of the lungs and forms the viceral layer. 
 This membrane receives blood vessels, and also nerves 
 from the sympathetic, pneumogastric, diaphragmatic 
 and intercostals. 
 
 Bronchia. — Terminal branches for the trachea, one 
 for each luug, they divide in this tissue, aifecting the 
 dichotomic division. The right bronchia is the largest. 
 They are perfectly cylindrical to their end, and'^Fe 
 composed of cartilaginous rings formed by elongated 
 small pieces of cartilages resting upon each other by 
 their extremities, (tliese disappear in the smallest tube,) 
 and of a muscular layer lining the whole extent of the 
 tube, which is covered by a mucous membrane. They 
 receive divisions of the bronchial arteries, veins and 
 nerves. Lymphatics pass to the bronchial glands. 
 
140 EQUINE ANATOMY. 
 
 LungSi — General disposition: Essential organs of 
 respiration, divided in two lateral moieties, described 
 as the right and left lung, tlie former being the larger. 
 Form : Together they have the form of the thoracic 
 cavity, each representing half of a cone with two faces, 
 three borders, a base and an apex. 
 
 Faces. — External is convex; internal offers an ante- 
 rior part resting on the anterior mediastinum, an exca- 
 vation for the reception of tlie heart, the root of the 
 lungs ; a posterior part resting on the posterior medias- 
 tinum, the thoracic groove and oesophageal fissure. The 
 right lung has also a small lobule on that face. Base : 
 Concave and moulded on the anterior face of the 
 diaphragm ; on the right lung it has a deep notch for 
 the posterior vena cava. Apex : Forms tlie anterior 
 lobule of the lung. Borders : Superior is convex 
 and rests in the vertebro-costal groove ; the inferior 
 is thin, with a large notch on the left lung for the 
 heart ; tlie posterior bounds the base or diaphragmatic 
 face. Structure : Serous envelope, the pleura. Tissue 
 proper, of a rose color, soft but resisting, elastic, very 
 light, divided in small lobules by conjunctive partitions, 
 each lobule being formed of pulmonary vesicles col- 
 lected and comnmnicating together witli a bronchial 
 tube ; each vesicle has a membrane proper lined by 
 pavimentous epithelium and is covered with capillajy 
 
THORAX. 141 
 
 vessels on its surface. The blood vessels of the lungs 
 are functional branches of the pulmonary artery and 
 nutritive divisions of the bronchial arteries and veins ; 
 the nerves come from the sympathetic and pneumo- 
 gastric; the lymphatics are arranged in superficial and 
 deep layers. 
 
 Heart. — General view: Hollow muscle divided by 
 a longitudinal septum in two masses, and each of these 
 by a transverse groove in two others, forming four cav- 
 ities, two superior, the auricles, two inferior, the ven- 
 tricles. Situation : opposite the third and sixth ribs, 
 in front of the diaphragm. Form: conoid. Direction: 
 obliquely, backwards, downwards, and slightly from 
 right to left. Size and weight : ten and one quarter 
 inches long, seven and a lialf at its base from back- 
 wards forwards, and five to five and a half from side 
 to side ; the average weight is six and three-quarter 
 pounds. 
 
 External aspect. — Yentricular mass: has two faces, 
 right and left, both divided by a super o-inferior fissure 
 in two portions, the posterior of which forms the left 
 ventricle. Connected through the pericardium to the 
 pleura and hmgs, this mass has two borders, one ante- 
 rior, obliquely backwards ; one posterior, almost verti- 
 cal. Its apex is formed by tlie left ventricle. Its base 
 has two arterial and two auriculo-ventricular openings. 
 
142 EQUINE ANATOMY. 
 
 Auricular mass. — This has three faces, a superior 
 with the openings of the anterior vena cava and azy- 
 gos in front, and pulmonary veins behind ; right face 
 with the openings of the posterior vena cava, coronary 
 and brachial veins ; and a left face embracing the aorta 
 and pulmonary arteries. Its extremities are anterior 
 ciud posterior, its base resting on the ventricular mass. 
 
 Internal aspect. — Cardiac septum divided into au- 
 ricular, with the cicatrix of the foramen of Botal ; and 
 ventricular much thicker. The right ventricle has 
 two walls, known as anterior and posterior. They have 
 fleshy columns of three kinds ; an apex, not extending 
 to the point of the heart ; a base, with the pulmonary 
 opening furnished with sigmoid valves, and the auri- 
 culo-ventricular opening presenting the tricuspid valve 
 secured by its borders to ventricular walls by the cordse 
 tendinosse. 
 
 The right auricle presents an anterior cul de sac 
 furnished with fleshy columns of the second and 
 third kinds : a posterior wall showing the fossa ovalis, 
 an external wall with venous openings, and internal 
 wall smooth, a superior wall with venous openings, a 
 base having the auriculo- ventricular opening. 
 
 The left ventricle has its walls covered with 
 fleshy columns ; its apex forms the point of the heart ; 
 the base presents the aortic opening, with tlie sigmoid 
 
THORAX. 143 
 
 valves and the auriculo-ventricular, witli the mitral 
 valve. 
 
 The right auricle covers the auriculo-ventricular 
 opening, and on its superior face has the openings 
 of the pulmonary veins, from four to eight in number. 
 
 Structure : Annular fibrous frame, made of four 
 bands, one for each orifice at the base of the ventricu- 
 lar mass. Muscular tissue composed of uniting and 
 proper fibres of the ventricles and auricles. The fibres 
 proper of the ventricles form a cone open at both ends. 
 The uniting fibres cover the external surface of the 
 ventricles, twist around them and penetrate into and 
 line the inside of the ventricular cavities. In the auri- 
 cles the uniting fibres form two thin bands goin^from 
 one to the other ; tlie proper fibres divide into fasci- 
 culi disposed in rings, round the auriculo-ventricular 
 openings, or in sphincters round the openings of the 
 veins. Blood vessels are represented by the coronary 
 arteries and veins. The nerves come from the great sym- 
 pathetic and pneumogastric. It has two serous mem- 
 branes, an internal or endocardium, lining the cavities 
 and extending into the cavity of the blood vessels ; an 
 external or pericardium, having a fibrous cone for a 
 frame, on the inside of which is spread the serous mem- 
 brane proper or two layers, parietal covering the 
 fibrous cone, and a visceral resting on the lieart itself. 
 
144 EQUINE ANATOMY. 
 
 This membrane receives blood from the mediastinal 
 arteries ; it has also some lymphatics. 
 
 AXGEIOLOGY. 
 
 Arteries, — Pulmonary. — Kisesf rom the right ventri- 
 cle, runs upward and backwards in a cm*ved direction 
 and above the left auricle divides in two branches, one 
 for each lung, where thej ramify. Connections : To 
 the right with the aorta, in front and behind is em- 
 braced by the auricles and cardiac vessels ; near its 
 middle is united to the aorta by the obliterated ductus 
 arteriosus. 
 
 Primitive aorta. — Rises from the left ventricle, 
 where it forms the sinuses of the aorta, runs upwards 
 and slightly forwards, and after two or two and a half 
 inches divides into the anterior and posterior aorta, its 
 terminal brandies. Connections : On the right with 
 the auricular mass ; on tlie left with the pulmonary 
 artery. Its collateral branches are the cardiac or cor- 
 onary arteries, divided into right and left. The right 
 rises in front of the primitive aorta, passes under the 
 anterior auricle and divides into a vertical branch 
 placed in the right vertical fissure of the ventricular 
 mass, and one horizontal running in the horizontal 
 groove. The left rises opposite the right, passes be- 
 hind the pulmonary artery under the left auricle, and 
 
THORAX. 145 
 
 divides into two brandies, one horizontal and one ver- 
 tical, disposed like the ri2;ht cardiac. These tv7o arteries 
 anastomose with those of the opposite side, and from 
 their division send collateral branches to the muscular 
 tissue of the heart. 
 
 Anterior aorta. — Tiie shortest of the terminal 
 branches, runs obliquely upwards and forwards above 
 the right auricle, under the trachea on the left side of 
 the anterior vena cava, and terminates by the two 
 branches : 
 
 1. Brachial OR axillary artery. — Running a course 
 forward, between the layers of the mediastinum under 
 the trachea, it reaches the entrance of the thorax, twists 
 round the first rib, into the axillary space and becomes 
 humeral (see page 31). 
 
 It gives off eight collateral branches : 
 
 1 The DORSAL. — Synonyms. Dorso-muscular, run- 
 ning towards the second intercostal space, through 
 it outside the thorax, bends slightly backwards and 
 ramifies into the muscles of the anterior part of the 
 dorsal region, having a larger branch passing for- 
 ward and upwards near the superior border of the neck 
 to anastomose with the superior cervical. It gives oif 
 one collateral branch, the subcostal, which passes into 
 the costo- vertebral groove backwards, giving off the 
 second, third and fourth intercostal arteries, and tcrmi- 
 
146 EQUINE ANATOMY. 
 
 n:ites in forming the iiftli alone or with another branch 
 from the first posterior intercostal. ■ 
 
 2 The SUPERIOR CERVICAL. — Synonyms. Cervico-mus- 
 cular ; runs outside the thorax through the first inter- 
 costal space, passing upwards and forwards under the 
 complexus major muscle, reaches the second cervical 
 vertebrse and anastomoses with the occipito-muscular 
 and the dorsal arteries. It gives for collateral branches 
 the first intercostal, muscular and tegumentary brandies 
 to the superi'.)r cervical regions. 
 
 3. The VERTEBRAL. — Passiug inside the first rib, out- 
 side the trachea and the inferior cervical ganglion, and 
 under the transverse process of the seventh cervical 
 vertebrae, enters the trachelian foramen, runs forwards 
 and upwards to the atlas, where it anastomoses with 
 the occipital. Its external, superior and inferior collat- 
 erals go to the muscles of the neck ; its internal to form 
 the median spinal. 
 
 4. The INTERNAL THORACIC OR MAMMARY. — Descending 
 inside the first rib to the sternum, then backwards upon 
 its superior face, it terminates at the base of the xyphoid 
 cartilage by the anterior abdominal, which passes out- 
 side the thorax under that cartilage, on the superior 
 face of the rectus abdominis muscle, where it ramifies 
 and finally anastomoses with tlie posterior abdominal, 
 and by the asternal artery, which lies inside the cartil- 
 
THORAX. 147 
 
 aginous circle of the false ribs, runs upwards, sending 
 intercostal collateral branches, and anastomoses with 
 the thirteenth intercostal. The mammary furnishes 
 superior brandies to the pericardium and pleura, inferi- 
 or branches to the pectoral muscles, and external rami- 
 fications to anastomose with the intercostals. 
 
 5. The EXTERNAL THORACIC. — Tumiug over the an- 
 terior border of tlie first rib, it runs backwards inside 
 the two portions of the deep pectoral muscles in which 
 it ramifies. 
 
 6. Tlie inferior cervical or trachelo-muscular. — 
 Passing outside the gulf of the jugulars, inside the 
 sterno-prescapularis, it terminates by an ascending and 
 descending muscular branch. 
 
 7 and 8, — Sus and subscapular. Described in tlie 
 arteries of the anterior extremity (see page 31). 
 
 Posterior aorta. — True continuation of the primi- 
 tive aorta. It passes upwards and backwards, forming 
 a curve called the arch of the aorta, reaches the left 
 side of the inferior face of the vertebral column, fol- 
 lows the vertebral bodies, gradually coming to the 
 median line, passes through the diaphragm, into the 
 abdomen as far as the last intervertebral articulation, 
 and terminates by the four iliac arteries. Its collaterals 
 are divided into thoracic and abdominal branches. 
 
 Thoracic collaterals. — 1. Intercostal arteries: Sev- 
 
148 EQUINE ANATOMY, 
 
 enteen in number. Thirteen are from the thoracic por- 
 tion of the posterior aorta, the iirst from the cervical 
 artery, and the three following from the subcostal (see 
 page 145) ; they run through the intercostal space and 
 divide into a superior or dorso-spinal artery, an ascend- 
 ing branch going to the muscles of the dorsal region ; 
 and an inferior, intercostal proper, or descending 
 branch running along the posterior border of tlie rib 
 downwards to anastomose with branches of the inter- 
 nal thoracic, of the anterior and posterior abdominal 
 and even circumflex iliac arteries. The intercostal ar- 
 teries form the parietal branches of the thoracic 
 aorta. 
 
 2. Broncho- (ESOPHAGEAL. — Visceral branch of the 
 thoracic aorta, rises from the convexity of the arch 
 of the aorta and near the bifurcation of the trachea, 
 gives off the two bronchial arteries ramifying with the 
 bronchia ; and the oesophageal, divided into superior 
 and inferior, which run above and below the oesophagus 
 backwards to anastomose with branches of tlie gastric. 
 
 3. Diaphragmatic — See description of diaphrag- 
 matic region, page 151. 
 
 Abdominal collateral. — See description of the ab- 
 dominal cavity, page 59. 
 
 Terminal branches. — See arteries of the hind ex- 
 tremity and pelvic cavity, pages 59 and 151. 
 
THORAX. 149 
 
 Veins. — Cardiac or coronary. — The small cardiac 
 empties from the walls of the right ventricle into the 
 right auricle. The great cardiac empties also into the 
 right auricle inside of the opening of the posterior vena 
 cava, after receiving the bronchial veins. 
 
 Anterior vena cava. — Formed by the two jugulars 
 and the two axillary veins, terminates on top the right 
 auricle, receiving in its course the internal mammary, 
 the vertebral, the superior cervical, the dorsal and the 
 great vena azygos, which last receives the first lumbar 
 and intercostal veins. 
 
 Posterior vena cava. — See description of the ab- 
 domen, page 172. 
 
 Lymphatics. — Those of the thoracic cavity consist of 
 three ganglions: 1 — A series of small granulations 
 placed near the oesophagus and receiving the posterior 
 lymphatics of this organ ; 2 — The bronchial ganglions, 
 situated at the bifurcation of the trachea and receiving 
 the pulmonary lymphatics ; 3 — Two long masses of 
 lobules at the inferior face of the trachea, into whicli 
 the lymphatics of the pericardium, heart and a part of 
 those from the trachea and oesophagus empty. The 
 lymphatics of the tlioracic walls are : 1 — A mass of 
 small granules on each side of the dorsal column ; 2 — 
 A large mass at the base of the xyphoid appendix ; 
 3 — Some small ones attached to the thoracic vessels. 
 
150 EQtJINE ANATOMY. 
 
 NEUROLOGY. 
 
 Seventeen pairs of dorsal nerves from the spinal mar- 
 row, all of which are alike, having a superior branch, 
 running towards the spinous process of the dorsal ver- 
 tebrae, ramifying in the spinal muscles and the skin of 
 the dorso-lumbar region; and an inferior branch which 
 runs downwards between the intercostal spaces and end 
 in the intercostal, pectoral and abdominal muscles. The 
 first and second pair cooperate to form the brachial 
 pelxus (see page 63). 
 
 Dorsal portion of the sympathetic. — From the 
 inferior cervical ganglion to the diaphragm it forms 
 a double chain of ganglions, seventeen in number, situ- 
 ated in the costo-vertebral groove, continued posteriorly 
 by the lumbar sympathetic. It has afferent branches 
 coming from the dorso-spinal nerves and efferent 
 branches in small number, among which the small and 
 great splanchnic only are important. The latter leaves 
 the main trunk near the sixth or seventh ganglion, 
 runs backwards, penetrates the abdomen, where it ter- 
 minates in the semi-lunar or solar plexus (see abdomnal 
 cavity, page 174). 
 
CHAPTER YIIT. 
 
 DIAPHRAGMATIC RKOION. 
 
 Diaphragm.— Situated between the thoracic and ab- 
 dominal cavities, obliquely downwards and forwards. 
 In form it is flattened from forwards backwards, wider 
 above, convex on its anterior, aud concave on its pos- 
 terior faces. It is divided into a phrenic, central or 
 aponeurotic portion, and a peripheric or fleshy portion. 
 Attachments : By the tendons of its two fleshy pillars 
 on the bodies of all the lumbar vertebrse, by its fleshy 
 peripheral digitations on the superior face of the xyphoid 
 cartilage and the internal face of the last twelve ribs 
 near their inferior extremity. Structure : In the centre 
 of the phrenic portion is a foramen for the posterior 
 vena cava ; through the right pillar, one for the oeso- 
 phagus; between the two pillars another for the pos- 
 terior aorta and tlioracic duct. Action : Essentially 
 inspiratory. 
 
 ArterieSt — Diaphragmatic: Two or three small 
 branches coming from the posterior aorta and ramify- 
 ing in the muscle. 
 
CHAPTER IX. 
 
 ABDOMEN. 
 
 OSTEOLOGY. 
 
 Lumbar VERXEBRji:. — ^S^ls^^i. General characters : 
 They are longer and wider than the dorsal ; tlie supe- 
 rior spinous process is short, thin, with a rough crest 
 on the apex ; the transverse processes are very large, 
 liorizontal and flattened from above below ; the ante- 
 rior articular facets are liollow and the posterior prom- 
 inent and tooth-like. 
 
 Specific characters. — The vertical diameter of the 
 body diminishes and the transverse diameter increases 
 from forwards backwards ; the transverse processes of 
 the first and second incline backwards, the third and 
 fourth are nearly straight, the fifth and sixth are bent 
 forward and are quite thick ; the posterior border of 
 the fifth has a wide articular facet, the sixth has one 
 on both the anterior and posterior borders. 
 
 SYJVDESMOLOGY, 
 
 Articulation of the two last lumbar vertebrji:. — 
 By wide facets o^ the bordei'S of the transverse processes 
 forming planiform diarthrosis, united by ligamentous 
 fibres and with one synovial capsula. 
 
ABDOMEiN^. 153 
 
 MYOLOGY. 
 
 The muscles of the abdomen are supported exter- 
 nally by the abdominal tunic. They nnite on the medi- 
 an plane forming the white line, and are four in num- 
 ber. 
 
 1. Tunica abdominalis. — A vast expansion of yel- 
 low elastic tissue, spread over the external muscles, 
 thick near the pubis and along the wliite line, and be- 
 coming tliinner towards its circumference. Posteriorly 
 it becomes lost in the inguinal region, and gives origin 
 to the testicular envelope known as the dartos. Ac- 
 tion : assists the abdominal muscles in supporting the 
 intestinal mass. 
 
 2. White line. — Linea alba. Formed by the inter- 
 crossing of the aponeurosis of the abdominal muscles, 
 it extends from the xyplioid cartilage of the sternum 
 to tlie anterior border of the pubis. 
 
 3. Great or external oblique of the abdomen. — 
 Synonyms : Costo-abdominalis, (G). Qbliqus externus 
 abdominis, (P). Structure : fleshy and aponeurotic por- 
 tions. Attachments : fleshy portion, on tlie external 
 face of the thirteenth or fourteenth last ribs, on the 
 aponeurosis of the great dorsal muscle ; by its internal 
 border it gives origin to its aponeurosis ; aponeui-otic 
 portion, on the linea alba, the anterior border of the 
 
154 EQUINE ANATOMY. 
 
 pubis, posteriorly it divides and gives origin to the 
 crural aponeurosis and the crural arch. Action : Ex- 
 piratory. 
 
 Internal crtjbal aponeurosis. — Lines the internal 
 face of the leg, covering the muscles of that re- 
 gion. 
 
 Crural arch, Fallopius or Poupart's ligament. — 
 Extends from the anterior border of the pubis to the 
 external angle of the ilium. Inside of the pectineal 
 insertion of the small psoas muscle it forms the anterior 
 line of the crural ring. 
 
 Inguinal canal. — An inf undibuliform canal through 
 which the means of support for the testicles or the 
 external mammary vessels pass from the abdomen. It 
 presents a superior and an inferior opening. 
 
 4. Small or internal oblique of the abdomen. — 
 Synonyms. Ilio-abdominalis, (G). Obliquus internus 
 abdominis, (1*). Structure : like the preceding. Attach- 
 ments : Fleshy portion, to the external angle of the 
 ilium and the crural arch ; aponeurotic portion, to the 
 internal face of the cartilages of the false ribs, and the 
 linea<ilba. Action: Expiratory. 
 
 5. Great straight of the abdomen. — Synonyms. 
 Sterno-pubialis, (G). Rectus abdoniin is, (P). Attach- 
 ments : the cartilages of the four last sternal and first 
 asternal ribs, inferior face of the sternum, the internal 
 
ABDOMEN. 155 
 
 face of the great oblique and the anterior border of the 
 pubis. Action : Principal flexor of the vertebral 
 column. 
 
 6. Transverse muscle of the abdomen. — Syno- 
 nyms. Lumbo-abdominalis, (G). Transversalis abdom- 
 inis, (P). Costo-abdominalis internus, (L). Situated on 
 the most internal part of the abdominal walls. It is 
 attached to the internal face of the false ribs, transverse 
 process of the lumbar vertebra8e,|xyphoid cartilage of 
 the sternum and linea alba. Action : Compresses the 
 abdominal organs against the spine. 
 
 Muscles of the Sub-Lumbar Region.— Nine in num 
 ber, covered by the iliac fascia or lumbo-iliac aponeu- 
 rosis. 
 
 1. Great psoas. — Synonyms. Sub-lumbo-trochineus, 
 (G). Lumbo-femoral, (L). Psoas magnus, (P). Sit- 
 uation : under the transverse processes of the lumbar 
 vertebrge. Attachments : On the body of the two last 
 dorsal and all the lumbar vertebrse, inferior face of the 
 two last ribs, transverse processes of the lumbar vertebrae 
 and internal trochanter of the femur. Action : Flexor 
 and rotator of the thigh, flexor of the lumbar 
 region. 
 
 2. Iliac psoas. — Synonyms. Ilio-trochineus, (G). 
 Iliacus, (P). Composed of two fleshy bodies. Attach- 
 ments : On the iliac surface, external angle of the ili- 
 
156 EQUINE ANATOMY. 
 
 uni, sacro-iliac ligament, ilio-pectineal crest and the 
 internal trochanter. Action : Flexor and rotator of 
 the thigh. 
 
 3. Small psoas. — Synonyms. Psoas of the loins, 
 (B). Sub-lumbo pubialis or iliacus, (G). Psoas par- 
 vus (P). Lumbo-iliacus (L). It is semi-penniform. 
 Attachments : On the body of the three or four last 
 dorsal and of all the lumbar vertebrae, ilio-pectineal 
 eminence, and lumbo-iliac aponeurosis. Action : Flexor 
 of the pelvis on the spine, arches directly or laterally 
 the ischio-lumbar region, tensor of the lumbo-iliac 
 aponeurosis. 
 
 4. Square muscle of the loins. — Synonyms. Sacro- 
 costalis, (G). Sacro-lumbalis, (P). Attachments : The 
 sacro-iliac ligament, posterior border of the last rib, 
 the transverse processes of the lumbar vertebrae, the in- 
 ternal face of the three or four last ribs. Action : 
 Draws the ribs backwards and inclines the lumbar por- 
 tion of the spine. 
 
 5. Inter-transversal of the loins. — Synonyms. 
 Inter-transversalis lumborum, (P). Atta3hments : The 
 anterior and posterior border of the transverse processes 
 of the lumbar vertebrae. Action : These five muscles 
 incline the lumbar region laterally. 
 
ABDOMEN. 157 
 
 SPLAlVCHi\OLOG¥. 
 
 Peritoneum. — A serous membrane lining the abdom- 
 inal cavity and forming a parietal and visceral layer. 
 The former passing over the different regions of the 
 abdomen, gives rise to the ligaments, mesentery and 
 epiploon, viz: in the sus- sternal region it forms a fal- 
 ciform band extended from the umbilicus to the liver ; 
 passing over the diaphragmatic region, it forms the 
 right, left and common ligaments of the liver, the car- 
 diac ligament surrounding the oesophagus; behind the 
 liver it furnishes the hepato-gastric ligament, from 
 which rise the great or gastro-colic and gastro-splenic 
 epiploon; in the lumbar region, it presents the hepa- 
 tico-renal ligament, that of the lobe of Spigel, the great 
 mesentery proper supporting the small intestine, the 
 colic mesentery, meso-coecum and meso-colon. Tovrards 
 the pelvic cavity it forms the three ligaments of the 
 bladder ; in males it covers the dilated portion of the 
 efferent canals, the vesicula seminalis and reflex 
 round the rectum. In females it forms three liga- 
 ments, called wide, round, or ligaments of the 
 ovary. 
 
 The visceral layer forms an external envelope to all 
 the abdominal organs except the kidneys. 
 
 Structure : connective tissue covered with pavimen- 
 
158 EQUINE ANATOMY. 
 
 tous epithelium, blood vessels, lymphatics, and nerves 
 from the diaphragmatic, lumbar, intercostal and great 
 sympathetic systems. 
 
 ABDOMINAL ORGANS. 
 
 In the anterior region : stomach, liver and spleen. 
 In the superior region : pancreas, kidneys, superre- 
 nal capsules and ureters. In the right and left hy- 
 pochondriac, the flanks and inferior region, the in- 
 testines. In the posterior region : the pelvis and its 
 contents. 
 
 Stomach. — Situation : posterior face of the dia- 
 phragm. Dimension : twelve to fifteen quarts. Form : 
 elongated, laterally flattened from forward backward, 
 curved upon itself and constricted in its middle. Divi- 
 sion : Two faces, two curvatures and two extremities. 
 Faces, convex and smooth. Curvatures, the great in- 
 ferior, convex and gives attachments to the great epip- 
 loon ; the smaller concave, and attached to the liver by 
 the hepato-gastric ligament. Extremities : the left 
 forms a large conical tuberosity, the right is continued 
 with the duodenum. 
 
 The internal face is lined by mucous membrane, 
 varying in aspect in the left and right portion, and pre- 
 sents two openings, the cardiac and pyloric. 
 
 Structure. — Serous membrane envelops the whole 
 
ABDOMEN. 159 
 
 organ, and furnishes the great epiploon, cardiac liga- 
 ment and hepato-gastric ligament. Muscular coat formed 
 of three layers, one of which belongs essentially to the 
 right extremity ; the left has three coats. Mucous mem- 
 brane, in the left extremity is covered with white, thick 
 epithelium, in the right with fine simple cylindrical 
 epithelium. In its structure we find tubular, mucous, 
 and pepsine glands. Arteries : gastric, splenic, right and 
 left epiploic and pyloric. Yeins : satellites of the ar- 
 teries. Lymphatics, emptying in the reservoir of Pec- 
 quet. Nerves, from the pneumogastric and solar plexus. 
 Liver.— Situation : obliquely downwards and to the 
 left, to the right of the diaphragmatic region. Weight, 
 about eleven pounds. Form : irregularly elliptical, flat- 
 tened from forward backward, thick in its centre, thin 
 at its borders. Division : In three lobes. The whole 
 organ has two faces and a circumference. The ante- 
 rior face is convex, and lias a groove for the posterior 
 vena cava; the posterior is smooth and convex, with a 
 groove for the portal vein, hepatic blood vessels, nerves 
 and ducts. The circumference is divided into a 
 supej'ior or left border, offering from right to left the 
 right ligament of the liver, the groove for the vena 
 cava, a notch for the oesophagus, the left ligament of 
 the liver. The inferior or right border presents the 
 two notches separating tlie three lobes. The right lobe 
 
160 EQUINE ANATOMY. 
 
 is the medium in size, and has on its posterior face the 
 lobule of Spigel ; the left lobe is the largest. Mode of 
 attachment : Four ligaments, one for each lobe, and one 
 to the phrenic portion of the diaphragm. {Structure : 
 Serous membrane covering the faces entirely, except 
 over the fissures. Fibrous or Glisson's capsule, an en- 
 velope dipping into the hepatic tissue, and sending 
 from its internal face numerous partitions, which pen- 
 etrate between the hepatic granulations. Proper tis- 
 sue of the liver, composed of polyhedric granulations 
 or lobules, in each of which are found the hepatic or 
 biliary cells, biliary ducts, afferent vessels, branches 
 of the portal vein and hepatic artery, the ramifications 
 of the first being called the interlobular or sub hep- 
 atic veins ; an effervent vessel with a lobular or supra 
 hepatic vein, lymphatic and connective tissue. Excre- 
 tory apparatus : ductus choledochus, emptying in the 
 duodenum. It is composed of a fibrous membrane, a 
 cylindrical epithelium and racemose glands. Blood 
 vessels: hepatic artery. Yeins: postal and supra hep- 
 atic. Lymphatic : abundant, empty in the sub-lumbar 
 reservoir of Pecquet. Nerves : from the solar plexus, 
 pneumogastric and diaphragmatic filaments. 
 
 Spleen. — Form: falciform. Direction and situation: 
 to the left of the diaphragmatic region, obliquely 
 downwards and forwards. Division : Two faces, two 
 
ABDOMEN. 161 
 
 borders, a base and an apex. Faces : external, convex ; 
 internal concave, it touches the large colon. Borders : 
 posterior thin and convex ; anterior concave, has a lon- 
 gitudinal fissure for the blood vessels and nerves, and 
 gives attachment to the great epiploon. The base rests 
 on the left kidney, and receives tlie suspensory liga- 
 ment. The apex is thin. Weight, thirty-two ounces. 
 Mode of attachments: The suspensory ligament and 
 the great epiploon. Structure : A serous membrane, 
 peritoneal covering ; a fibrous tunic, wliich from its in- 
 ternal surface send trabecules, dividing the organ into 
 numerous spaces, in which tlie splenic pulp is con- 
 tained, as well as the Malpighian bodies. Artery : 
 the splenic. Yeins : its satellites. Lymphatics : on the 
 external surface of the organ. Nerves : from the solar 
 plexus. 
 
 Pancreas. — Abdominal salivary gland. — Situa 
 tion : sub-lumbar region, forward of kidneys, poste- 
 rior to liver and stomach. Weight : seventeen ounces. 
 Form : irregular and variable, flattened from above be- 
 low and traversed by the pancreatic ring. Faces : 
 superior is in connection with the aorta, posterior vena 
 cava, coeliac trunk, solar plexus, right kidney and su- 
 pra-renal capsule ; inferior is related to base of coecum 
 and tlie colon. Borders : anterior is in connection with 
 the duodenum and left sac of the stomach ; posterior 
 
162 EQUINE ANATOMY. 
 
 has a notch for posterior vena cava. Extremities : right 
 adheres to the duodennm, left looks towards base of 
 spleen. Structure : Like the salivary glands. Excre- 
 tory apparatus consists of two canals, that of Wirsung 
 and its accessorius ; they open in the duodenum, oppo- 
 site each otlier. 
 
 Kidneys.— Situation : To the left and right of the 
 sub-lumbar region, the right being more forward than 
 the left. Form : riglit is like the heart on a playing 
 card, the left resembles a haricot bean. Division : Two 
 faces, smooth ; three borders, internal forms the fissure 
 or hilus. Weight: right, about twenty-seven ounces, 
 left, twenty-five. Internal aspect : a horizontal sec- 
 tion sliows : 1. The renal pelvis with the sinus renalis, 
 the crest, and laterally the arms of the pelvis. 2. Cor- 
 tical, and 3. Medullary layers of the tissue proper. 
 Structure : a fibrous membrane, external envelope ; 
 tissue proper divided into cortical and medullary layer. 
 In the first are found the Malpighian corpuscles, in the 
 latter, the tubuli urinriferi. Blood vessels : renal ar- 
 tery and vein. Lymphatics : numerous. Nerves : from 
 the solar plexus. Development : they appear early in 
 the foetus. 
 
 Ureters. — Form, membranous canals. Origin: the 
 inf undibulium of the pelvis. Termination : obliquely 
 into the bladder, through its muscular coat. Structure : 
 
ABDOMEN. 165 
 
 three coats, an external of connective and elastic tis- 
 sue, a median muscular, an internal mucous. 
 
 Ovaries. — Situated in the abdominal cavity, hang- 
 ing to the sub-lnmbar region, a little posterior of the 
 kidneys. Modes of attachments : a fold of peritoneum 
 or broad ligament. Structure : a serous coat perito- 
 neal, a tunica albnginea and a tissue proper divided 
 into medullary and cortical layers ; in the latter are 
 found the Graafian vesicles, composed of a fibrous en- 
 velope and a granular membrane, which contains the 
 ovulam or ovum. Blood vessels : ramification of the 
 utero-ovarian artery. Lymphatics : go to the sub-lumbar 
 ganglion. Nerves come from the small mesenteric 
 plexus. ^. 
 
 Oviducts. — Fallopian or uterine tubes. Situation : 
 in the broad ligament, near its anterior border ; begins 
 at the ovary by the pavilion or ostium abdominale, and 
 terminates in the cul de sac of the uterine horn by the 
 ostium uterinum. Structure: an external layer of se- 
 rous membrane, a middle muscular and internal mu- 
 cous. Functions : carries the ovulum to the uterus and 
 tlie seminal fluid to the ovulum. 
 
 Uterus, — Situation : in the abdominal cavity, sub- 
 lumbar regions at tlie entrance to the pelvic cavity. 
 Division : A body and two cornua. Body has two 
 faces, superior and inferior ; an anterior extremity or 
 
164 EQUINE ANATOMY. 
 
 fundus, and a posterior separated from the vagina by 
 the neck or cervix of the uterus. Tlie cornua have an 
 inferior curvature, a superior, shorter ; an anterior and 
 posterior extremity. Modes of attachment : A sus- 
 pensory or broad ligament. Interior offers many mu- 
 cous folds and three compartments or cavities, one for 
 the body, two for the cornua. Tlie former is prolonged 
 in the vagina hy the Jleur epanouie. Structure: a se- 
 rous tunic peritoneal, a muscular coat with longitudi- 
 nal and circular fibres, a mucous membrane raised, into 
 folds, containing many simple or ramified glands. 
 Blood vessels : branches of the uterine and utero-ova- 
 rian arteries. Lymphatics, numerous. Nerves sup- 
 ported by the small mesenteric and pelvic plexuses. 
 
 Intestines« — Division : Small and large. 
 
 Small intestine. — Length, twenty-four yards. Form, 
 cylindrical. Course, from the right sac of the stomach, 
 runs forward, turns backwards round the base of the 
 ccecum, passes to the left flank, forms many circumvo- 
 lutions, returns to the right and ends in tlie ccecum, 
 below the origin of the large colon. Mode of attach- 
 ments: by the stomach, coecum, and principally the 
 mesentery. Interior has longitudinal folds, villi, glan- 
 dular and follicular openings, communicates with the 
 stomach by the pyloric opening, and with the coecum 
 by the ileo-coecal valve ; near the former it shows the 
 
ABDOMEN. 165 
 
 openings of the ducts of the liver and pancreas. Struc- 
 ture : a serous coat expansion of the mesentery ; a mus- 
 cular coat of two layers, one longitudinal superficial, 
 the other circular deep ; a mucous membrane soft, 
 spongy, vascular with thin cylindrical epithelial cells 
 and numerous villi. Glands : of Brunner, of Lieber- 
 kulm or Galcati, solitary glands, aggregated follicles 
 or glands of Feyer. Blood vessels : arteries, from the 
 great mesentery and coeliac trunk. Yeins empty into 
 the portal vein. Lymphatics from three superposed 
 networks in the mucous membrane, l!^erves, from 
 tlie solar plexus. 
 
 Large intestine. — Division : Coecnm, colon and 
 rectum. Ccecum — Situation : the right hypocondriac 
 region, obliquely downwards and forwards. Dimen- 
 sion, little over three feet. Capacity, seven and a half 
 gallons of fluid. Form : conical, terminating in a 
 point inferiorly, with circular furrows interrupted by 
 four longitudinal muscular bands. Mode of attach- 
 ment : adhering directly to the sub-lumbar region, and 
 to the origin of the colon, by the meso-ccecum. In- 
 terior presents valves or transverse ridges, the ileo- 
 coecal valve, and above it the opening of the colon. 
 Structure : a serous coat, longitudinal and circular 
 muscular fibres, a mucous membrane with solitary fol- 
 licles, glands of Lieberkuhn, and a few villi. Blood 
 
166 EQUINE ANATOMY. 
 
 vessels : the coecal arteries and veins. Lymphatics, 
 emptying into the sub-himbar receptacle. Nerves, from 
 the great mesenteric plexus. 
 
 Colon. — Division : Large, double or fixed, and small 
 or floating. 
 
 Laege colon. — Length, ten to thirteen feet. Capacity, 
 eighteen gallons. Form and general disposition : rep- 
 resents a large canal with dilatations and contractions, 
 its surface being crossed by longitudinal bands of mus- 
 cular tissue and folded in two; each part being itself 
 doubled in its turn, thus forming four portions. Course: 
 from the arch of the eoecum, the first portion runs for- 
 ward to the posterior face of the diaphragm, forms the 
 suprasternal flexure, turned downwards and to the left; 
 the second portion continues backwards to the entrance 
 of the pelvis, where inflected to the left it forms the 
 pelvic flexure ; the third portion, running forward above 
 and to the left of the second, reaches the diaphragm 
 and forms the diaphragmatic or gastro-hepatic flexure ; 
 the fourth portion bound to the first, extends upwards 
 and backwards to a level with the base of the eoecum, 
 where it ends in the small colon. Modes of attach- 
 ment : by the meso-coecum and meso-colon, by its ad- 
 herence to the pancreas and eoecum directly. Internal 
 surface : like that of the eoecum. Structure : a serous 
 or peritoneal layer, a muscular coat in two layers, and 
 
ABDOMEN. 167 
 
 a mucous coat like the coecum. Blood vessels : the co- 
 lic arteries and satellite veins. Lymphatics, empty in 
 the reservoir of Pecquet. Nerves, from the great mes- 
 enteric plexus. 
 
 Small colon. — Length : ten feet. Form : like the 
 small intestine with its external surface bosselated, and 
 provided with tw^o wide longitudinal muscular bands. 
 Course : from the terminal end of the large colon into 
 the left flank, ending in the rectum. Mode of attach- 
 ment : colic mesentery. Interior : valvular folds, like 
 tlie coecum and colon. Structure: a serous, muscular 
 and a mucous coat, like tliose of the colon. Blood 
 vessels : from the small and a branch of the great mes- 
 enteric artery, veins empty into the postal vein. Lym- 
 phatics : as numerous as in the small intestine. Nerves : 
 from the posterior mesenteric plexus. 
 
 Rectum, — See pelvic cavity, page 177. 
 
 AXGEIOLOGY, 
 
 Artekies — ABDOMINAL AORTA. — Continuation of the 
 posterior aorta after it passes through the diaphragm, 
 terminating at the lumbo-sacral articulation by quad- 
 rif urcation forming the two external and internal iliacs. 
 Its collaterals are the lumbar and middle sacral for 
 parietal branches, the coeliac axis, great mesenteric, 
 
168 EQUINE ANATOMY. 
 
 renal, small mesenteric, spermatic, and small testicular 
 for visceral branches. 
 
 Ltjmbar — Five or six in number, analogous in their 
 course and disposition to the inter-costals, terminating 
 by superior and inferior muscular branches. 
 
 Middle sacral. — Often missing, and when found 
 rises between the two internal iliacs and runs on the 
 inferior face of the sacrum backwards, losing itself 
 gradually. 
 
 CcELiAc AXIS. — Rises from the inferior face of the 
 aorta and after a short course divides into three 
 branches. 
 
 1. Gastric. — Passes upon the left extremity of the 
 stomach and near the oesophagus,divides into an ante- 
 rior and posterior gastric, both ramifying upon the cor- 
 responding faces of the organ. It gives a third 
 branch which passes along the oesophagus, enters the 
 thorax and divides into two branches, which anasto- 
 mose with the two oesophageal. 
 
 2. Hepatic. — Huns outward to the right to reach 
 the posterior face of the liver, which it enters dividing 
 into numerous branches. It has for collaterals the pan- 
 creatic, the pyloric, and right gastro-epiploic. 
 
 a. Pancreatic. — Small branches to the pancreas. 
 h. Pyloric — From the main trunk as it enters the 
 fissure of the liver, it passes towards the small curva- 
 
ABDOMEJSr. 169 
 
 ture of the stomach, and anastomoses round the pylorus 
 with the posterior gastric and right gastro-epiploic. 
 
 c. Right gastro-epiploic or omental. — Passes along 
 the great curvature of the stomach between the layers 
 of the great omentum, and anastomoses by arcade with 
 the left gastro-epiploic, after sending gastric and omen- 
 tal branches or collaterals. It furnishes also the duo- 
 denal, anastomosing with the first artery of the small 
 intestine. 
 
 3. Splenic. — The largest of the three branches of 
 tlie coeliac trunk, places itself in the fissure of the inter- 
 nal border of the spleen, down to its apex, runs between 
 the two layers of the great omentum and goes to anas- 
 tomose with the right gastro-epiploic, having thus formed 
 the left gastro-epiploic. From both collateral branches 
 gastric, splenic and epiploic are sent in all directions. 
 
 Great mesenteric. — A trunk from one to one and 
 a half inches long, rising from the abdominal aorta 
 about two inches behind the coeliac axis, and soon divides 
 into three fasciculi, left, right and anterior. 
 
 a. Left fasciculus. — Gives fifteen to twenty arte- 
 ries, ramifying in the small intestines, running between 
 the layers of the great mesentery and at some distance 
 from the small curvature of that organ, dividing into 
 two branches, which go to anastomose with correspond- 
 ing branches from the neighboring arteries, forming 
 
170 EQUINE ANATOMY. 
 
 arches from which a number of branches start to rami, 
 fy in the intestinal tract. The first anastomoses with 
 the duodenal, and the last with the ileo-coecal artery. 
 
 h. Right fasciculus. — A short trunk which soon di- 
 vides into four branches : 
 
 1. Ileo-ccecal. — Anastomosing with the last artery 
 of the left fasciculus. 
 
 2. Two ccECAL. — Divided into internal or superior, 
 and external or inferior. Both located in the fissure 
 of the coecum, running down to the apex, where their 
 divisions anastomose after sending collateral branches 
 to the organ. At its origin the external coecal gives 
 off the artery of the coecal arch following the concavity 
 of the arch, where it disappears. 
 
 3. HiGHT OR direct COLIC. — Ruus iu the right flex- 
 ure of the colon to the pelvic curvature, where it anas- 
 tomoses with the left colic, furnishing collateral 
 branches to that portion of the large intestine. 
 
 c. Anterior fasciculus. — Furnishes two principal 
 trunks : 
 
 1. Left colic or retrograde. — Acting to the left 
 portion of the large colon as the direct colic does for 
 the right, and anastomosing with it at the pelvic curv- 
 ature. 
 
 2. First artery of the small colon. — Placed in 
 the posterior fold of the small mesentery, to anasto- 
 
ABDOMEN. 171 
 
 mose with the first division of the small mesenteric 
 artery. 
 
 d. Innominated branches — To the lymphatic glands, 
 supra-renal capsules, mesentery and pancreas. 
 
 Small mesenteric. — Descending from the posterior 
 abdominal artery, some four and half to six inches 
 behind the great mesenteric. It runs between the lay- 
 ers of the small mesentery and forms thirteen or four- 
 teen branches, which act somewhat like the arteries of 
 the small intestines and ramifying in the floating colon 
 and rectum. 
 
 Renal or emulgent. — One for each kidney, in the 
 substance of which they penetrate by its notch or in- 
 ferior face. 
 
 Spermatic or great testicular in the male, running 
 outside the abdominal cavity into the inguinal canal 
 with the other constituents of the spermatic cord, and 
 after many flexuosities reaching the testicle, in which 
 it disappears ; and 
 
 Utero-ovarian in the female ; lodged between 
 the folds of the broad ligament, and dividing into an 
 ovarian artery to the ovary and a uterine to the cornu 
 of the uterus. 
 
 Small testicular.— In male; distributed to the 
 various parts of the spermatic cord. 
 
 Uterine. — In female, to the uterus proper. These 
 
172 EQUINE ANATOMY. 
 
 do not always rise from the abdominal aorta, but more 
 commonly from the external iliac. 
 
 Veins. — Posterior vena cava. — Beginning at the 
 pelvis by the pelvic crural trunks (see page 182) placed 
 under the bodies of the lumbar vertebrae, reaches the 
 superior border of the liver, passes through the phren- 
 ic portion of the diaphragm to the posterior and ex- 
 ternal part of the right auricle of the heart, being 
 thus divided into a sub-lumbar, hepatic and thoracic 
 portions. The numerous collateral afferents are : the 
 diajDhragmatic, the vena portse, the renal, the sperma- 
 tic and several lumbar veins. The vena portse does 
 not empty directly into the vena cava, but indirectly 
 by the supra hepatic veins, which rise from its subdi- 
 vision, the subhepatic veins. It is constituted by three 
 principal roots : the great and small mesenteric and 
 splenic veins; it receives as collateral affluents the 
 right gastro-epiploic and the anterior gastric veins. 
 
 Lymphatics. — 1. Those of the rectum and floating 
 colon are placed at the base of the tail on each side 
 of the spliincter, also along the small cui'vature of the 
 rectum and between the folds of the mesentery. 
 Their efferent branches unite to the divisions of the 
 sublumbar ganglions. 
 
 2. Those of the folded colon form a double chain 
 on the tract of the colic arteries. Their branches 
 
ABDOMEN. 173 
 
 unite to those of the small intestines, and empty in 
 the reservoir of Pecquet. 
 
 3. The lymphatics and ganglions of the coecum are 
 on the course of the arteries. Their branches unite 
 to the trunk of the small intestine. 
 
 4. The small intestine has some thirty ganglions 
 placed in the thickness of the mesentery near the 
 origin of the great mesentric artery ; they all empty 
 in the reservoir of Pecquet. 
 
 5. The stomach has large ganglions on the small and 
 smaller ones on the large curvature. Their efferent 
 branches empty some directly in the thoracic duct, 
 some after uniting with the anterior trunk of the intes- 
 tinal lymphatics. 
 
 6. The spleen offers several ganglions in its fissure, 
 from which efferent vessels go to the thoracic duct. 
 
 7. Tlie liver presents a few in the posterior fissure, 
 whose vessels unite to those of the stomach and 
 spleen. 
 
 Thoracic duct. — General confluent of all the lym- 
 phatics of the body except those of the right anterior 
 leg, right half of the head, neck and thorax. It ex- 
 tends from the first lumbar vertebrae to the entrance 
 of the thorax, beginning by the sub-lumbar reservoir 
 or cistern of Pecquet on a level with the great mesen- 
 teric artery. Course : from the reservoir passes be- 
 
174 EQUINE ANATOMY. 
 
 tween tlie pillars of the diapliragm, and in various 
 ways arrives towards the sixth dorsal vertebrae, where 
 it leaves the aorta, crosses the azjgos vein between the 
 axillary arteries, comes out of the chest and then ter- 
 minates with a dilation in the anterior vena cava at 
 the juncture of the two jugulars. 
 
 Great lymphatic vein. — Confluent of the lymphat- 
 ics of the right leg, right half of the head, neck and 
 thorax. It opens at the junction of the jugulars by 
 one or two openings, alone or by anastomosing with 
 
 the thoracic duct proper. 
 
 NEUROLOGY. 
 
 Six pairs of lumbar nerves, whose superior branches 
 ramify in the spinal muscles and integuments of the 
 lumbar region and haunch. The inferior ramify in 
 the abdominal muscles and the region of the flank. 
 The third pair furnishes three inguinal nerves — one in- 
 ternal, two external. 
 
 Lumbar portion of the sympathetic. — Continuation 
 of the dorsal chain ; it has the same aspect, and lies 
 against the small psoas muscle, runs to the lumbo-sac- 
 ral joint, where it becomes the sacral portion. Its af- 
 ferent branches come from the lumbar pairs. Its 
 
ABDOMEN. 175 
 
 efferent brandies collect into two or three nerves, and 
 by their anastomoses form the posterior mesenteric 
 plexus, which gives branches to the floating colon and 
 rectum, some to the anterior mesenteric plexus, and to 
 the spermatic arteries forming the spermatic plexus ; 
 the last branches co-operating to form the pelvic plexus. 
 
CHAPTEH X. 
 
 PELVIS. 
 
 OSTEOLOGY. 
 
 Sacrum. — Formed by the union of the five sacral ver- 
 tebrae. Division : Two faces, two borders, a base, an 
 apex and a central canal. Faces : Superior presents 
 the spinous processes forming the sacral spine, bent 
 backwards and diminishing in length posteriorly; it 
 offers on each side the four supra-sacral foramina. 
 The inferior face is smooth and shows the lines of sep- 
 aration of the vertebrae, and on each side the four sub- 
 sacral foramina. The borders are thick and concave, 
 rough posteriorly, having forward a broad, rough au- 
 ricular surface, to articulate with the ossa innominata. 
 The base offers on the median line the anterior orifice 
 of the sacral canal and the anterior articular head of 
 the body of the first sacral vertebrae ; on the sides the 
 articular processes and the anterior notches of that ver- 
 tebrae, and outside the two large facets for articulation 
 
PELVIS. 177 
 
 with the last himbar bone. The apex presents the pos- 
 terior opening of the sacral canal, the posterior articu- 
 lar cavity, the body of the last sacral vertebrae, the 
 vestiges of the articular processes and the posterior 
 notches of that vertebrae. The sacral canal is a part 
 of the rachidian canal, triangular, and is narrowing 
 backwards. 
 
 OssA iNNOMiNATA — Scc postcrior extremity, page 45. 
 
 SYIVDESMOLOOY. 
 
 Sacro-iliac joint. — Arthrodia : Facets of the sides 
 on the base of the sacrum and tlie facets of the internal 
 face of the ilium. Sacro-iliac, superior ilio-sacral, in- 
 ferior ilio-sacral, sacro-sciatic, or ischiatic ligaments. 
 One small synovial capsula. Yery limited sliding 
 motion. 
 
 MYOLOGY. 
 
 See posterior extremity, page 52 and following 
 pages. 
 
 SPLAX( ECOLOGY. 
 
 Rectum. — Posterior portion of the digestive canal 
 and continuation of the floating colon, from which it 
 differs by the absence of ridges, is thicker and has 
 more dilatable walls and is susceptible of large disten- 
 
178 EQUINE ANATOMY. 
 
 sion. Modes of attachment : the meso-reetmn, a fold 
 of the colic mesentery, a fold of the peritoneum, the 
 suspensory ligaments of the penis and a triangular 
 fasciculus of muscular fibres, a prolongation of its 
 fleshy coat. Structure : a serous membrane, a fleshy 
 coat of longitudinal and annular fibres, a mucous mem- 
 brane with transverse and longitudinal folds ; arteries 
 from the small mesenteric and internal pudic ; nerves 
 from the pelvic or hypogastric plexus. 
 
 Anus. — The posterior opening of the digestive ca- 
 nal, pierced at the posterior extremity of the rectum 
 under the base of the tail. Structure : mucous mem- 
 brane of the rectum, muscular fibres of the rectum 
 forming an internal sphincter, an external sphincter, 
 a retractor or ischio-anal muscle and the skin, fine 
 and very adhering to the muscular tissue underneath. 
 
 Bladder — Form : ovoid with a large extremity or 
 rounded cul de sac turned forward, and a posterior 
 extremity, the neck, continued hy the urethra. Its 
 average weight is about sixteen ounces. Modes of at- 
 tachment : a fold of the peritoneum forming the three 
 liofaments of the bladder. Its interior shows the vesi- 
 cal trigone. Structure: a mucous membrane intern- 
 ally, a muscular coat, longitudinal, circular, oblique and 
 spiroid fibres, and a serous coat in its anterior region ; 
 arteries from the vesico-prostratic ; nerves from the 
 
PELVIS. ITU 
 
 pelvic plexus and some inferior branches of the two 
 last sacral pairs. 
 
 Yagina. — Situation : in the pelvic cavity between 
 the rectum and the bladder. Internal surface ridged 
 bj longitudinal folds. Structure : an external coat 
 muscular, an internal mucous ; and arteries from tlie 
 internal pudic ; nerves from pelvic plexus. 
 
 YuLTA. — Situated below the anus. It presents an 
 external opening with two lips, a superior and inferior 
 connnissure ; the latter lodges the clitoris covered by a 
 fold of mucous membrane called the prepuce. At 
 some four or five inches from this external opening the 
 meatus urinarius and its valve. The hymen is a mem- 
 brane which separates the cavity of the vagina from 
 that of the vulva. Structure : a mucous membrane, 
 an erectile body named the vaginal bulb, the posterior 
 and the anterior con^^trictor muscles of the vulva, two 
 muscular ligaments and an external layer of skin. 
 
 ANGEIOLOGY. 
 
 Arteries. — External iliac or crural trunk. — Ex- 
 ternal brancli of the termination of the abdominal 
 aorta, running obliquely downwards, backwards and 
 outwards to be continued by the femoral. Its collat- 
 erals are the small testicular or uterine (see page 171) 
 
180 EQUINE ANATOMY. 
 
 and the circumflex iliac running at a right angle out- 
 wardly to divide into anterior and posterior branches, 
 ramifying in the abdominal muscles. 
 
 Internal iliac ob pelvic trunk. — Extends from 
 the last lumbar vertebrae downv^ards, outwards and 
 backwards to the in sertio n of the small psoas, where 
 it terminates by the obturator and the iliaco-f emoral . 
 Its collateral branches are : 
 
 1. Umbilical — Almost entirely obliterated in the 
 adult, and found extending to the fundus of the 
 bladder, placed in the free border of its lateral liga- 
 ments. 
 
 2. Internal pudic. — In the male ; running back- 
 wards along the superior border of the internal obtu- 
 rator muscle, into the pelvic cavity to the ischial arch, 
 where it terminates^ the bulb of the urethra. Its 
 principal collaterals are the vesico-prostatic, which 
 ramifies iti the bladder, and the vesicula seminalis. 
 In the female, it ends in the vagina by rectal, vulvar, 
 vaginal and bulbous branches ; its principal collateral 
 is the vaginal artery. 
 
 3. Sub-sacral or lateral sacral. — Runs back- 
 wards under the sub-sacral foramen to the posterior 
 extremity of the sacrum, where it ends by the ischia- 
 tic and lateral coccygeal after furnishing collaterals to 
 the surrounding parts and four spinal branches. 
 
PELVIS. 181 
 
 a. IscHiATic. — Runs through the ischiatic ligament 
 to ramify in the ischio-tibial muscles. 
 
 h. Lateral coccygeal. — Extends backwards to tlie 
 end of the tail between the caudal vertebrae and the 
 depressor muscles of that region, giving off muscular 
 and cutaneous collaterals. 
 
 c. Median caudal — branch from the right lateral 
 coccygeal runs between the two depressor muscles of 
 the tail ; backwards to its end, where it terminates. 
 
 4. Iliaco-muscular or ilio-lumbar.- — Passes out- 
 wardly between the psoas iliacus and the bone that it 
 covers, and near the external angle of the ilium term- 
 inates by muscular branches. 
 
 5. Gluteal. — E-amifying in the gluteal muscles 
 after passing outside the pelvic cavity through the 
 great sciatic notch. "^ 
 
 a. Obturator. — Directed backwards'aua aovvuwaruis # 
 towards the obturator foramen, runs through it and ^^ 
 divides into branches to the internal crural and ischio- 
 tibial muscles ; amongst these branches we find the 
 cavernous, which creeps backwards and inwards towards 
 the crus penis, where it dips and furnishes the posterior 
 dorsal of the penis, which goes along the superior bor- 
 der of that organ to anastomose with the anterior 
 dorsal. V 4^ 
 
 Iliaco-fb^ioral. — Passes outwards the tendon of 
 
 kwards anoaownwai^s^ 
 
182 EQtJINE ANATOMY. 
 
 the psoas parvus above the origin of the anterior rectus 
 muscle, and ends in the patellar muscles. 
 
 Veins. — The internal iliac formed by the iliaco-f em- 
 oral, obturator, iliaco-muscular, gluteal, lateral sacral 
 and internal pudic, unite with the external iliac to form 
 the pelvi-crural trunk. 
 
 Lymphatics. — Empty into the sub-lumbar ganglions. 
 
 IVEUROLOGY. 
 
 Sacral nerves — Five pairs. Superior branches 
 like those of the other spinal nerves. The inferior 
 branch co-operates to form the lumbo-sacral plexus (see 
 abdominal extremity, page 63) by the first, second 
 and third pairs; the fourth constitutes the internal 
 pudic, and the fifth the anal or hemorrhoidal nerve. 
 
 Sacral portion of the sympathetic. — Formed by 
 four ganglions united by branches communicating 
 with the spinal sacral nerves, and at the posterior ex- 
 tremity of which starts a last nerve, the end of the 
 sympathetic cordon, wliich terminates in various ways. 
 
CHAPTER XI. 
 
 CA.Ur)i^L REGIOISr. 
 
 OSTEOLOGY. 
 
 Caudal vektebjrjs. — Fifteen to eighteen in number, 
 in which tlie general characters of the vertebrse are 
 easily recognized in the anterior ones, but which by 
 degrees disappears till the last, where it constitutes a 
 small elongated somewhat conical bone. 
 
 SYJ^DESMOLOGY. 
 
 Articular surfaces are the facets of the bodies of 
 the vertebrae. Means of union are an inter articular 
 cartilaginous meniscus and longitudinal ligamentous 
 fibres. 
 
 MYOLOGY. 
 
 Three sacro-coccygeal and one ischio-coccygeal mus- 
 cles. 
 
 1. Sacro-coccygeal superiok. — Synonyms. Erec- 
 tor coccygis, (P). Attachments : Summits and sides 
 of three or four last processes of the sacral spine and 
 
18i EQUINE ANATOMY. 
 
 coccygeal vertebrae. Action: Elevates or pulls the 
 tail to one side. 
 
 2. SACRO-coccYaEAL INFERIOR. — Sjnonjms. Depres- 
 sor coccjgis, (F). Attachments : The inferior face of 
 the caudal vertebrae. Action: Depresses or inclines 
 the tail to one side. 
 
 3. Sacro COCCYGEAL LATERALIS. — Sjnonyms. Cur- 
 vator coccygis, (P). Attachments : The spinous pro- 
 cess of tlio last lumbar vertebrae and of the caudal 
 vertebrae. Action : Inclines the tail sideways. 
 
 4. IscHio-coccYGEAL. — Syuonyms. Compressor coc- 
 cygis, (P). Attachments : The sacro-ischiatic liga- 
 ment, the ischiatic crest and the sides of the last sac- 
 ral and two first caudal vertebrae. Action : Depresses 
 the entire caudal appendage, 
 
 AIVGEIOLOGY. 
 
 Arteries. — Lateral and median caudal (see page 181). 
 Veins. — Satellites of the arteries. 
 
 NEUROLOGY. 
 
 Nerves — Six to seven pairs. They form by the 
 union of their branches, two long nerves, one under 
 the depressor of the tail, the other under the sacro- 
 caudal lateralis, which lose themselves into the liga- 
 ments and the muscles of the tail. 
 
CHAPTEH XII. 
 
 ^FPEN DIX. 
 
 Genital organs of the male.— Situated partly in the 
 inguinal region, in the pelvic cavity and between the 
 two internal crural regions. 
 
 Testicular envelopes— Scrotum. — Single cutaneous 
 pouch covering the two testicles, thin, covered with short 
 fine hairs and lubricated by unctuous secretion of se- 
 baceous follicles. 
 
 Dartos. — Contractile tissue, one for each testicle, 
 resting on each other on the median line, separated 
 above for the passage of the penis ; covered externally 
 by the scrotum, to which it is adherent, and covering 
 the fibrous and erythroid tunics. It is composed of 
 elastic and unstriped muscular fibres. 
 
 Cremaster or tunica erythroides. — Bright red 
 band attached above to the peritoneal surface of the 
 lumbar aponeurosis, expanding below and terminating 
 upon the 
 
 Fibrous tunic. — (Infundibulum fascia), continuous 
 
186 EQUINE ANATOMY. 
 
 with the transversalis fascia, it forms the most com- 
 plete covering of the serous parietal layer of the tuni- 
 ca vaginalis, to which it is closely adherent. 
 
 Tunica vaginalis. — Diverticulum of the abdomi- 
 nal cavity, and lined by the peritoneum. Its interior 
 forms a serous sac, which is elongated downwards, in- 
 wards and backwards, and is divided into a parietal 
 layer which lines the inside of the fibrous tunic, and a 
 visceral layer covering the testicle and the spermatic 
 cord. These two layers are made continuous by a pos- 
 terior frgenum. The tunica vaginalis contains usually 
 a certain quantity of serous fluid. 
 
 Testicles. — External conformation : oval, flattened 
 sideways and suspended at the extremity of the sper- 
 matic cord. It has two faces, smooth and round, an in- 
 ferior border convex and free, and a superior border 
 related to the epididymis. It is hanging in the tunica 
 vaginalis, through the testicular or spermatic cord, 
 formed by the spermatic vessels and the vas deferens. 
 Structure : 1 — A fibrous covering or tunica albuginea, 
 which is thicker towards the inner border of the organ 
 where it forms the corpus Higmori ; this membrane is 
 dense and inelastic ; 2 — A tissue proper, greyish yellow 
 pulp contained in the fibrous envelope. It presents the 
 tubuli seminiferi, in the axis of wliich are perceived 
 the spermatozoa and the remains of the spermatic cells. 
 
APPENDIX. 187 
 
 A section of the testicle shows the trabeculge testis, the 
 straight canaliculi (vasa recta), the rete testis continued 
 into the epididymis as the vasa efferentia ; 3 — Blood 
 vessels : tlie spermatic artery, the veins from the pam- 
 piniform plexus, the lymphatics are numerous ; 4 — the 
 nerves come from the sympathetic. 
 
 Epididymis. — It commences in the excretory canal of 
 the testicle, is an elongated body resting upon the su- 
 perior border of the testicle, having a middle portion, 
 flat on both sides, an anterior extremity, head or globus 
 major and a posterior, tail or globus minor, which is 
 continued by the vas deferens. Structure : a simple 
 ciliated epithelium resting on a proper amorphous 
 membrane, placed on unstriped circular fibres in the 
 efferent ducts ; and beyond a stratified ciliated epithe- 
 lium, a proper membrane and two layers of circular 
 and longitudinal unstriped fibres, protected by a fibrous 
 tunic. 
 
 Defere:nt canal — vas deferens. — A flexuous, then 
 straight duct, running from the globus minor to the in- 
 side of the pelvic cavity through the inguinal ring, in- 
 flected there backwards, suddenly dilated and terminat- 
 ing in the vesicula seminalis. Structure : a mucous 
 coat internally, covered by a contractile and a fibrous 
 tunic. 
 
 YESICULiE SEMINALIS AND EJACULATORY DUCT. Sit- 
 
188 EQUINE ANATOMY. 
 
 uated in the pelvic cavity, above the bladder and the 
 vas deferens, it has a middle portion covered by the 
 rectum ; an anterior extremity, the largest forming a 
 cul de sac ; a posterior extremity tapering to a narrow 
 neck and receiving at an acute angle the termination 
 of the vas deferens. Structure : an internal mucous 
 coat, a middle muscular and an external fibrous. 
 
 The ejaculatory ducts, formed by the union of the 
 vesiculse seminalis and the vas deferens, terminate in 
 the urethra on the side of the veru montanum. 
 
 Urethra. — A membranous canal extending from the 
 neck of the bladder to the end of the penis. Course: 
 from its origin backwards in the pelvic cavity, there 
 bonds downwards over the ischial arch between the 
 two roots of the corpus cavernosum, forward to the 
 head (glans) of the penis, terminating by the urethral 
 tube. It is divided into an intra pelvic or membran- 
 ous, and an extra pelvic or spongious portion. 
 
 Interior. — Constricted at its origin, it expands at the 
 prostate gland, forming the cul de sac of the bulb or 
 ventricle ; tlien contracts over the ischial arch, and 
 remains of the same size to the end. Behind the ure 
 thral tube is the fossa navicularis. On the mucous 
 membrane it presents the openings of the prostrate 
 gland, the urethral ridge or veru montanum and the 
 excretory canals of Cowper's glands. Structure : a 
 
APPENDIX. 189 
 
 mucous membrane, thin and having longitudinal folds ; 
 an erectile envelope or corpus spongiosum, covering the 
 extra pelvic portion only ; muscles, represented by that 
 of Wilson, the bulbo-cavernous or accelerator nrinse, 
 the ischio-urethral or compressor urinse and the trans- 
 verse perinei. Blood vessels, the two dorsal arteries of 
 the penis and nerves from the internal pudic and great 
 sympathetic. 
 
 Perineal aponeurosis. — Divided into superior and 
 deep layers. 
 
 Glands annexed — prostate. — Situated in the pelvic 
 cavity at the commencement of the urethra ; a con- 
 glomerated gland whose secretion is thrown into the 
 urethra. 
 
 Cowper's glands — OR SMALL PROSTATE. — Situated on 
 each side of the urethra, above the ischial arch, and 
 covered by the muscles of Wilson and ischio-urethral. 
 
 Corpus cayernosum. — Erectile stalk, base of the 
 penis and support of the urethra. Situated between 
 the thighs, prolonged beneath the abdomen, attached 
 to the ischial arch and terminating by the glans penis. 
 External conformation : it offers two lateral faces 
 plane ; a superior or dorsal border rounded ; an infe- 
 rior or urethral channeled for the reception of the 
 urethra ; a posterior extremity with two roots or crura 
 attached to the ischial arch, and covered by the erector 
 
190 EQUINE ANATOMY. 
 
 penis nniscle ; and an anterior extremity forming a 
 blunt point, surrounded by the spongy tissue of the 
 glands. It is attached by the two crura and the two 
 suspensory ligaments. Structure : erectile tissue, com- 
 posed externally of white, elastic, fibrous envelope, 
 sending by its inner face numbers of lamellar trabecu- 
 Ise. The blood vessels are the dorsal arteries of the 
 penis. Nerves from the internal pudic and great sym- 
 pathetic. 
 
 Penis. — Male organ of copulation. Extending 
 from the ischial arch between the thighs and the two 
 dartoid sacs, beneath the belly, where it terminates. 
 Divided into a fixed and a free portion, which is cov- 
 ered by the cutaneous fold of the skin, the sheath or 
 prepuce. The free portion at its anterior extremity 
 presents the urethral tube, the urethral sinus and the 
 sub-urethral notch. The penis has two suspensory 
 and retractile cords, composed of unstriped muscular 
 fibres, which draw it back into the sheath after erec- 
 tion. The sheath contains a large number of sebace- 
 ous or preputial glands, secreting an unctuous fatty 
 matter, the smegma preputii. 
 
 Genital organs of the female — ovaries, fallopi- 
 an TUBES, UTERUS, VAGINA, VULVA. — (Scc abdominal 
 and pelvic cavities, page 163.) 
 
 Mamm^. — Situated in the inguinal region, they 
 
APPENDIX. 191 
 
 form two hemisplierical masses, distinct from each 
 other and having in their centre the teat, nipple or 
 mammillge. Structm'c : composed of a yellow elastic 
 fibrous envelope ; tliey consist of a glandular tissue 
 made of acini, clustered in groups around the lactifer- 
 ous ducts, which, by their union, open in the galacte- 
 forous sinuses, from which rise the true excretory 
 canals of the glands. Much connective tissue unite 
 these acini. The arteries of the mammse come from 
 tlie external pudic ; the nerves from the first lumbar 
 nerve. Their function is to secrete the milk. 
 
CHAPTER XIII. 
 
 ARTERIAL SUBDIVISION, 
 
 MAIN TRUNK. 
 
 Primitive aorta. 
 
 Cardiac arteries. 
 Posterior aorta. 
 
 Intercostal. 
 
 Lumbar. 
 
 Diapliragmatic. 
 Middle sacral. 
 Bronclio-cesopliageal. 
 
 Bronchial. 
 (Esophageal. 
 Coeliac axis. 
 
 Gastric. 
 Splenic. 
 
 Hepatic. 
 
 Great mesenteric. 
 
 Left fasciculus. 
 
 COLLATERAL. 
 
 Rio^ht and left cardiac. 
 
 Intercostal, diaphrag- 
 matic, lumbar, mid- 
 dle sacral, broncho- 
 cesophageal, coeliac 
 axis, great and small 
 mesenteric, renal, 
 spermatic, small tes- 
 ticular or uterine. 
 
 Innominated. 
 
 Splenic, gastric, epi- 
 ploic branches. 
 
 Pancreatic branches, 
 pyloric artery. 
 
 Innominated. 
 
 TERMINATION. 
 
 Posterior and anterior 
 aorta. 
 
 External and internal 
 iliacs. 
 
 Inferior intercostal 
 proper, superior or 
 dorso-spinal. 
 
 Superior and inferior 
 muscular branches. 
 
 Muscular branches. 
 
 Bronchial and oesoph- 
 ageal arteries. 
 
 Superior and inferior. 
 Gastric, splenic, hep- 
 atic. 
 Anterior and posterior. 
 Left gastro epiploic. 
 
 Right gastro epiploic. 
 
 Three fasciculi — left, 
 right and anterior. 
 
 Arteries of small in- 
 testines. 
 
ARTERIAL SUBDIVISION. 
 
 193 
 
 MAIN TRUNK. 
 
 Right fasciculus. 
 
 Anterior fasciculus. 
 
 Small mesenteric. 
 Renal, or emulgent. 
 Spermatic, or utero 
 
 ovarian. 
 Small testicular, or 
 
 uterine. 
 Internal iliac. 
 
 Umbilical. 
 Internal pudic. 
 
 COLLATERAL. 
 
 Subsacral. 
 
 Iliaco-muscular. 
 
 Gluteal. 
 
 Obturator. 
 
 Artery corpus cavern- 
 
 osum. 
 Iliaco-muscular. 
 External iliac. 
 
 Circumflex iliac. 
 
 Femoral. 
 
 Anterior pudic. 
 
 Posterior abdominal. 
 External pudic. 
 
 Deep muscular. 
 Superficial muscular. 
 
 Umbilical, internal pu- 
 dic, iliaco-muscular, 
 gluteal, subsacral. 
 
 Yesico-prostatic, mus- 
 cular branches — 
 (male). Vaginal — 
 (female). 
 
 Innominated branch- 
 es. 
 
 M uscular branches, 
 and artery of corpus 
 cavernosum. 
 
 Small testicular, 
 cumflex iliac. 
 
 cir- 
 
 Anterior pudic, deep 
 muscular, superfi- 
 cial, small muscular 
 and saphena. 
 
 Muscular branches. 
 
 TERMINATION. 
 
 Ileo coecal, two coecal, 
 
 right colic. 
 Left colic, first artery 
 
 of floating colon. 
 Arteries of small colon 
 
 Uterine and ovarian. 
 
 Obturator and iliaco- 
 femoral. 
 
 Vesical branches. 
 Bulbous branches. 
 
 Ischiatic, lateral cau- 
 dal, median from 
 rio:ht caudal. 
 
 Muscular branches. 
 
 Posterior dorsal of the 
 
 penis. 
 Muscular branches. 
 Femoral. 
 
 Anterior and posterior 
 muscular branches. 
 Popliteal. 
 
 Posterior abdominal, 
 external pudic. 
 
 Subcutaneous abdom- 
 inal, anterior dorsal 
 of the penis (male), 
 mammary (female). 
 
 Muscular branches. 
 
 Muscular branches. 
 
194: 
 
 EQUINE ANATOMY. 
 
 MAIN TRUNK. 
 
 Small muscular. 
 
 Saphena. 
 Popliteal. 
 
 Posterior tibial. 
 
 Plantar. 
 
 Anterior tibial. 
 
 Pedal. 
 
 Perforating pedal. 
 Metatarsal pedal. 
 
 Digital. 
 
 Ungueal preplantar. 
 Plantar. 
 
 COLLATERAL. 
 
 Medullary of the fe- 
 mur. 
 
 Femoro-popliteal, ar- 
 ticular and muscu- 
 lar branches. 
 
 Posterior tibial mus- 
 cular branches, tib- 
 ial articular branch- 
 es, medullary tibial, 
 and branches to 
 anterior part of 
 hock. 
 
 From convexity of the 
 anastomos e s — two 
 superficial innomin- 
 ated, two deep inter- 
 osseous. 
 
 Muscular and peroneal 
 branches. 
 
 Articular and cutane- 
 ous branches. 
 
 Ligamentous and cu- 
 taneous branches. 
 
 Articular and tendin- 
 ous innominated, 
 perpendicular artery 
 of Percival, artery 
 of plantar cushion, 
 coronary plexus. 
 
 TERMINATION. 
 
 Muscular branches. 
 
 Cutaneous branches. 
 Anterior and posterior 
 tibial. 
 
 Two plantar. 
 
 Anastomose together 
 in the hock. 
 
 Pedal. 
 
 Perforating pedal, 
 
 metatarsal pedal. 
 With plantar. 
 Digital. 
 
 Plantar and preplan- 
 tar. 
 
 Anterior face of coffin 
 
 bone. 
 Plantar circle. 
 
 Anterior aorta. 
 
 Dorsal. 
 
 D)rsal, superior cer- 'Brachial or axillary, 
 
 vical, vertebral, in- 
 ternal thoracic, ex- 
 ternal thoracic, in- 
 ferior cervical, supra 
 and subscapular. 
 Su")-costal, second, 
 tliird and fourth in- 
 tercostal. 
 
 the right furnishes 
 the brachio-qephalic 
 trunk. 
 
 Muscular branches. 
 
ARTERIAL SUBDIVISION. 
 
 195 
 
 MAIN TRUNK. 
 Superior cervical. 
 
 Vertebral. 
 Internal thoracic. 
 
 External thoracic. 
 Inferior cervical. 
 
 Supra-scapular. 
 Subscapular. 
 
 Humeral. 
 
 Anterior radial. 
 Posterior radial. 
 
 Radio-palmar, or trunk 
 of interosseous met- 
 acarpal. 
 
 Sub-carpal arch. 
 
 Collateral metacarpal. 
 
 COLLATERAL. 
 
 First intercostal. 
 
 External, superior and 
 inferior muscular 
 branches, internal 
 spinal. 
 
 Superior branch to 
 pericardium and 
 mediastinum, inferi- 
 or and external mus- 
 cular branches. 
 
 Branches to latissimus 
 dorsi, posterior cir- 
 cumflex of the 
 shoulder, muscular 
 branches. 
 
 Prehumeral, or anter- 
 ior circumflex of the 
 shoulder, deep hu- 
 meral, epicondyloid, 
 artery of coraco- 
 radialis. 
 
 Articular and muscu- 
 lar branches. 
 
 Articular and muscu- 
 lar branches, inter- 
 osseous of fore- 
 arm. 
 
 Two posterior inter- 
 osseous, two anter- 
 ior interosseous. 
 
 Branches to supra-car- 
 pal arch, synovial 
 and tendinous bran- 
 ches anastomose to 
 anterior and poster- 
 ior interosseous. 
 
 TERMINATION. 
 
 Anastomoses with oc- 
 cipito-muscular and 
 dorsal. 
 
 With occipital. 
 
 Anterior abdominal, 
 and thoracic or as- 
 ternal. 
 
 Muscular branches. 
 
 Superior, or ascend- 
 ing, and inferior, or 
 descending. 
 
 Muscular branches. 
 
 Muscular branches. 
 
 Anterior and posterior 
 radial. 
 
 At knee joint. 
 
 Interosseous metacar- 
 pal, collateral meta- 
 carpal. 
 
 Supra-carpal arch, sub- 
 carpal arch. 
 
 Digital. 
 
196 
 
 EQUINE ANATOMY. 
 
 MAIN TRUNK. 
 Digital. 
 Carotid. 
 Occipital. 
 Occipito-muscular. 
 
 Cerebro-spinal. 
 Basilar trunk. 
 
 Median-spinal. 
 Internal carotid. 
 
 External carotid. 
 
 Glosso-facial. 
 
 Maxillo-muscular. 
 Posterior auricular. 
 
 Superficial temporal. 
 
 Subzygomatic. 
 
 Internal maxillary. 
 
 COLLATERAL. 
 
 Thyro-laryngeal, tliy- 
 
 ro-accessorius. 
 Prevertebral, mastoid, 
 
 atloido-muscular. 
 
 Branches to me- 
 dulla oblongata, 
 branches to annu- 
 lar protuberance, 
 posterior cerebel- 
 lar artery, anter- 
 ior cerebellar ar- 
 tery, two branch- 
 es to internal car- 
 otid. J 
 
 Glosso-facial, maxillo- 
 muscular, posterior 
 auricular. 
 
 Pharyngeal, lingual, 
 sublingual, inferior 
 and superior coro- 
 nary, innominated 
 branches. 
 
 TERMINATION. 
 
 Like in the hind ex- 
 tremity. 
 
 Occipital, internal and 
 external carotid. 
 
 Occipito-muscular and 
 cerebro-spinal. 
 
 Muscular branches. 
 
 "] One anterior for bas- 
 i ilar trunk, one pos- 
 I terior median-spi- 
 
 J nal, with posterior 
 cerebral. 
 
 Inferior dental, ptery- 
 goid, tympanic, 
 sphenoidal, deep 
 posterior temporal, 
 deep anterior tem- 
 poral, ophthalmic, 
 buccal, staphyline, 
 superior dental, na- 
 sal. 
 
 One posterior cere- 
 bral. 
 
 One anterior cerebral, 
 one median cerebral. 
 
 Superficial temporal, 
 internal maxillary. 
 
 One ascending and one 
 descending branch. 
 
 Muscular branches. 
 Muscular and parotid- 
 
 ean branches. 
 Anterior auricular, 
 
 subzygomatic. 
 Transversal of the 
 
 face and masseter- 
 
 ine. 
 Palato-labial. 
 
BONES. 
 
 197 
 
 MAIN TRUNK. 
 Ophthalmic. 
 
 Palato-labial. 
 
 COLLATERAL. 
 
 Muscular of the eye, 
 ciliary and lachry- 
 mal. 
 
 TERMINATION. 
 
 Meniugeal and nasal 
 branches. 
 
 Anastomose together, 
 and ramify in upper 
 lip. 
 
 BONES. 
 
 CENTERS OF OSSIFICATION. 
 
 Vertebrae, two princi- 
 pal, and five or six 
 complimentary. 
 
 Atlas, six. 
 
 Sacrum, five vertebrae. 
 
 Occipital, four. 
 
 Parietal, two. 
 
 Frontal, two. 
 
 Sphenoid, two. 
 
 Ethmoid, three. 
 
 Temporal, three. 
 
 Bones of ear, one. 
 
 Supermaxillary, one. 
 
 Teeth, one. 
 
 Intermaxillary. 
 
 Palate, one. 
 
 Pterygoid, one. 
 
 Zygomatic, one. 
 
 Lachrymal, one. 
 
 Nasal, one. 
 Turbinated, one. 
 Vomer, one. 
 Inferior maxillary, 
 
 two. 
 Hyoid, seven. 
 Sternum, six. 
 Rib, three. 
 Scapula, two. 
 Humerus, six. 
 Radius, three. 
 Cubitus, two. 
 Carpus, all one apiece. 
 Principal metacarpal, 
 
 two. 
 Small metacarpal, one. 
 Os suffraginis, two. 
 Os coronce, one. 
 Os pedis, one. 
 
 Sesamoid, one. 
 Navicular, one. 
 Ossa innominata, 
 
 three. 
 Ilium, two. 
 Ischium, two. 
 Pubis, one. 
 Femur, four. 
 Tibia, four. 
 Fibula, one. 
 Patella, one ; Tarsus, 
 
 one, except Os cal- 
 
 cis, two. 
 Principal metatarsal, 
 
 two. 
 Small metatarsal, one. 
 Phalanges, one apiece. 
 Sesamoids, one apiece. 
 Navicular, one. 
 
i 
 
 Webster Family Library of Veterinary Medicine 
 Cummings School of Veterinary Medicine at 
 Tufts University 
 200 Westboro Road 
 North Grafton, MA 01536 
 

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