Webster Family Library of Veterinary ^yledicine 
 Cummings School of Veterinary Medicine at 
 Tufts University 
 200 Westboro Road 
 North Grafton. MA 01536 
 
VETERINARY MEDICINE SERIES 
 
 No. 17 
 Edited by D. M. Campbell 
 
 FISTULA OF THE WITHERS 
 AND POLL-EVIL 
 
 BY 
 
 Major L. A. MERILLAT, Sr., V. C, N. A., 
 
 Editor, Department of Surgery, 
 
 .American Journal of Veterinary Medicine 
 
 Published by 
 
 Americ:in Veterinary Publishing Co., 
 
 Chicago 
 
Copyright, 1917, by 
 
 American Veterinary Publishing Co. 
 
 Chicago 
 
CONTENTS 
 
 FISTULA OF THE WITHERS Page 
 
 Introduction 7 
 
 The Withers 13 
 
 Pathogenesis 37 
 
 Symptoms 57 
 
 Treatment 67 
 
 POLL-EVIL 
 
 The Poll 105 
 
 Pathogenesis 113 
 
 Symptoms 121 
 
 Treatment 127 
 
PREFACE 
 
 There are several reasons why a manual on 
 this disease should be a part of the veterinary 
 literature of the day, the chief one being that 
 fistula of the withers is a very prevalent disease 
 of horses and thus exacts a big toll from the 
 horse industry. Another reason for bringing 
 it especially to the attention of readers of vet- 
 erinary literature is the deplorable fact that 
 its treatment has never been standardized in 
 the veterinary profession. Almost all long 
 known and common complaints of domestic 
 animals of a serious character are handled ac- 
 cording to definite plans, differing only in 
 minor details. The many conferences of our 
 teachers of surgery in association work, and 
 the interchange of ideas made possible by the 
 splendid periodicals which all progressive vet- 
 erinarians now read, as well as the profusion 
 of all kinds of literature that reaches everyone, 
 has fortunately created a standard of treat- 
 ment for nearly all of the more important ail- 
 ments of animals. 
 
 Not so, however, with fistula of the withers. 
 Each seems to have his own plan of treatment 
 and few, indeed, claim even a fair degree of 
 
6 PREFACE 
 
 success. Some are satisfied with caustics, oth- 
 ers with lancing and irrigations, others with 
 bacterins, while a few of the more daring pre- 
 fer radical surgery that removes the causative 
 elements. To these plans might also be added 
 that of those who avoid fistula of the withers 
 entirely, because of the discredit meddlesome 
 intervention generally brings them. 
 
 In every rural community of the Middle 
 West the empiric finds a fruitful field for ex- 
 ploitation in the many chronic, loathsome, half- 
 cured fistula of the withers found in the hands 
 of owners willing to try anything after having 
 given up in despair the various treatments that 
 have failed. 
 
 If this book will do no more than to inspire 
 the veterinary practitioner to approach this 
 ailment in a matter of fact manner and to han- 
 dle it according to the common laws of modern 
 surgical procedure; and if it will discourage a 
 continuance of the half-hearted and always un- 
 satisfactory methods in vogue, the effort will 
 not have been lost. The Author. 
 
 Camp Mills, N. Y., December, 1917. 
 
INTRODUCTION 
 
 The disease known universally among Amer- 
 ican veterinarians as fistula of the withers is 
 described at much greater length in the follow- 
 ing pages than has ever been done before in 
 veterinary literature. Most of the authors of 
 surgical subjects have dismissed this affliction 
 with a few w^ords, referring to it only incident- 
 ally as an occasional complication of harness 
 galls or other forms of trauma about the crest 
 of the neck and withers, but always without 
 dignifying it as an entity w^orthy of special 
 notice. Its frequent origin in the bursse on the 
 thoracic spines of the region and its develop- 
 ment independent of any apparent injury have 
 only recently attracted attention. In fact, 
 there are many who still entertain the opinion 
 that it is but a complication of a contusion in- 
 flicted by the collar, by rolling upon hard 
 ground, by striking against a low stable beam, 
 by rubbing against branches of trees while at 
 the pasture, or by bites from other horses. 
 Without ever having been able to attribute any 
 given typical fistula of the withers to a given 
 traumatism, the theory of traumatic origin 
 has been indifferently accepted as ample expla- 
 
8 INTRODUCTION 
 
 nation of its cause. Thus years have been 
 wasted in attacking the disease from without, 
 giving only casual attention to the "interior" 
 of the withers where it actually originates. 
 
 We do not insist that the names "fistulous 
 withers" or "fistula of the withers" are even 
 good appellatives for the disease we are about 
 to describe. On the contrary, a name less spe- 
 cially pathologic in its meaning would seem 
 more appropriate, since fistula is but a phase of 
 the entity as a whole. The name, inappro- 
 priate as it is, we retain because among our 
 American readers it has been consecrated by so 
 many years of usage that a change would lead 
 to no better understanding of our exposition or 
 argument. We retain the name, therefore, 
 with the full knowledge that it is appropriate 
 only for the latter stages of the disease and that 
 the fistula are but insignificant parts of the 
 total pathogeny. 
 
 Poll-evil, which we argue is but the same 
 condition attacking the atlantal bursa, has, on 
 the contrary, been more extensively described 
 by writers throughout the history of modern 
 veterinary science, and although it had been re- 
 ferred to always as a complication of a trauma- 
 tism in the earlier days, it was the first of these 
 two diseases to be recognized as a bursitis. It 
 has been designated as inflammation of the 
 
INTRODUCTION 9 
 
 bursa of the ligamentum nuchge and by some 
 writers as inflammation of the ligament itself. 
 No one has thus far been able to prove its def- 
 inite cause. Like fistula of the withers, ap- 
 parently for want of an explanation based on 
 demonstrable facts, it has always been attrib- 
 uted to bruisings of the poll. 
 
 While we do not entirely eliminate traimia- 
 tism as the cause of some cases of poll-evil and 
 some attacks of fistula of the withers, it has 
 been our experience that when injuries are the 
 cause, the wound or bruise is always apparent 
 and the disease advances into the depths of the 
 region by gradual stages from the initial focus 
 deeper and deeper until the interior is finally 
 attacked by the encroaching pyogenic process. 
 In ordinary cases of both of these afflictions, 
 the initial focus is always central, far down in 
 the depths of the body where external violence 
 can have but little influence. From this cen- 
 tral location the disease as gradually advances 
 in the outward direction in the ordinary case, 
 as it does inward in the exceptional cases due 
 to trauma. We have, therefore, no choice 
 than that of describing both poll-evi] and fis- 
 tula of the withers as having two distinct caus- 
 es, one a wound or bruise at the very surface, 
 and the other, and commonest, as yet imknown. 
 
 The prevalence of fistula of the withers and 
 
10 INTRODUCTION 
 
 poll-evil we have found to be much greater in 
 some localities than others. In some districts 
 it is actually an equine scourge, while in others 
 it is a rare occurrence. In southern California, 
 for example, veterinarians seldom if ever see 
 a typical fistula of the withers or poll-evil, while 
 in central Illinois it is a veritable horse plague. 
 In a recent conversation with an old horse 
 breeder in the latter location the information 
 was elicited that fistula was once as rare there 
 as in California. Asked if he had any theory 
 to advance as to the cause he seemed inclined to 
 attribute most cases to influenza, and colt dis- 
 temper, claiming that before these diseases be- 
 came prevalent from the interchange of horses 
 from shipping centers there were no cases of 
 fistula of the withers. The rarity of shipping 
 fever (influenza) in California, seems to add 
 logic to these observations. 
 
 But no matter what the cause may eventu- 
 ally prove to be, the veterinary practitioner is 
 today confronted with a serious disease of 
 horses that he must endeavor to control and 
 handle to the better satisfaction of horse breed- 
 ers and the public. To fall short of meeting 
 this requirement is one more adverse reflection 
 on our ability to meet the demands of our 
 growing live stock industry. To study, to ex- 
 periment with, to strive to curb, and to analyze 
 
INTRODUCTION 11 
 
 this affliction from every angle is therefore a 
 worthy enterprise. It is at least a problem of 
 the rural districts of the Middle West that is 
 neither well handled, nor, so far as we can per- 
 ceive, intelligently studied. 
 
 The loss in horses in Illinois from fistulse 
 alone reaches into the thousands. The loss to 
 veterinarians from their helplessness in han- 
 dling the cases and the discredit this state of 
 helplessness brings to the veterinary profession 
 are matters to be thoughtfully considered. 
 
 The fact that the treatment of poll-evil is no 
 longer an unsolved problem in veterinary sur- 
 gery, and that this treatment, now standard 
 for more than ten years, has proved as nearly 
 universally successful as any surgical depart- 
 ure can prove, and the further fact that this ail- 
 ment differs from fistula of the withers only in 
 matters governed by the location, should, it 
 seems to us, have spurred veterinarians to re- 
 sort to similar measures for handling both. The 
 fact that the latter is located in a more com- 
 plex region and requires an operation of great- 
 er magnitude is, we believe, the only reason 
 why no advance has been made in its treat- 
 ment. 
 
 Better surgery from every angle by which 
 good surgery is judged (anesthesia, restraint, 
 asepsis, hemostasis and wound treatment) 
 
12 INTRODUCTION 
 
 will, we believe, eventually solve the problem 
 of fistula of the withers in the same way that 
 the much simpler operation has solved that of 
 poll-evil. 
 
THE WITHERS 
 
 The region of the anatomy called the withers 
 has no well defined limits. The word "with- 
 ers," therefore, while academic in hippology, 
 is not usually found indexed in text hooks on 
 anatomy. It is described as to shape in the 
 study of types, but seldom as regards to its 
 component parts, except in surgical anatomy 
 - — a branch of veterinary science that is as yet 
 ill-developed. The horse judge studies the 
 profile of the withers very carefully because the 
 general appearance of any given horse depends 
 a great deal upon its shape, its size and the 
 measurements of its dimensions. The surgeon 
 studies not only its shape and dimensions, but 
 its constituent parts as well and their complex 
 and disadvantageous arrangement from the 
 surgical point of view. 
 
 It is important to note that the withers may 
 be high, low, narrow, broad, steep, sloping, 
 long or short, and that any two or three of 
 these characteristics combine to determine the 
 various types of withers of different individ- 
 uals. Graphic writers in describing equine 
 types often use such terms as sharp witliers, 
 low withers, liigli withers, long withers, thick 
 
14 FISTULA AND POLL-EVIL 
 
 withers, muscular withers, effaced withers, 
 prominent withers, each of which, in addition 
 to being descriptive in the study of profile, is 
 equally suggestive in the study of etiology of 
 affections of these parts and their surgical 
 treatment. Each one of these characteristics 
 contributes to a different etiologic factor as 
 well as a different surgical problem. 
 
 Boundaries 
 
 The withers, although having ill-defined lim- 
 its, may be said, for surgical study, to extend 
 from the crest of the neck anteriorly, to a point 
 posteriorly, where the dorsal spines descend to 
 the level of the back. The second dorsal spine 
 may be selected as the uniform anterior limit, 
 but posteriorly no line can be drawn, because 
 some withers end abruptly toward the level 
 of the back, while others slope gradually to a 
 more distant posterior point between the eighth 
 and twelfth spines. The highest point is al- 
 most universally at the fifth spine. The second 
 dorsal spine may, therefore, be said to repre- 
 sent the anterior boundary, the fifth spine the 
 summit and any point between the eighth and 
 twelfth dorsal spines the posterior boundary. 
 In the downward direction, the withers may be 
 said to descend to the bodies of the vertebrae 
 mesially and to the distal border of the scapu- 
 
THE WITHERS 15 
 
 lar cartilage, (cartilage of prolongation) lat- 
 erally. With these boundaries as a point of 
 departure, each structure comprising the with- 
 ers might be studied per se, but from the sur- 
 gical point of view its study en masse is of first 
 importance. 
 
 Component Parts 
 
 The withers are composed of skin, fascia, 
 muscles, ligaments, cartilage, bones, blood ves- 
 sels, lymphatics and nerves. These are com- 
 bined in a very complex and exceedingly disad- 
 vantageous manner, since in situ they form a 
 pyramid whose base is loosely arranged while 
 the summit is dense. The summit of the with- 
 ers, under the skin, is composed of hard liga- 
 mentous structures fixed firmly to the underly- 
 ing bones. From this point, the layers of which 
 the region is constituted separate from each 
 other in the downward direction, permitting 
 thereby a ready filtration of pus into constant- 
 ly deeper and more inaccessible fortresses, and 
 constituting a favorable field for the fruitful 
 development and undisturbed sojourn of in- 
 flammatory processes of a chronic character. 
 The base of the pyramid is bounded laterally 
 and ventrally by bones (the scapula and bodies 
 of the dorsal vertebra) while anteriorly and 
 posteriorly its component structures extend 
 
16 FISTULA AND POLL-EVIL 
 
 without change of arrangement into the neck 
 and back. Thus pus within the withers after 
 filtering downward finds its only exit by trav- 
 eling first in either of these two directions, and 
 ultimately to the surface of the body at points 
 remote from the seat of development. It is 
 this complex arrangement that affords the im- 
 pregnable intrenchment of pathological prod- 
 ucts and that is responsible for the refractory 
 character, the extreme seriousness and the un- 
 varying chronicity of the disease known as fis- 
 tula of the withers. 
 
 The Skin 
 
 The skin covering the withers possesses noth- 
 ing unusual except the thickness of the subcut- 
 em along the median line anteriorly where the 
 heavy connective tissue of the mane begins. Pos- 
 terior to the summit of the withers the skin is of 
 normal thickness, but is separable only with 
 difficulty from the aponeurosis of the fleshy 
 panniculus whose fixed attachment is at the 
 level of the fourth or fifth spine. Very often, 
 however, the skin is the seat of scars superven- 
 ing harness and collar injuries which fuse it 
 into the underlying ligaments, fascia or mus- 
 cles as the location may determine. 
 
 Panniculus Carnosis (Cutaneous Muscle) 
 
 This muscular structure is a prominent feat- 
 ure of the withers in that its chief attachment 
 
THE WITHERS 17 
 
 is to the summit. Along the region of the with- 
 ers its fibers, unhke those of any other part of 
 the body, are vertical, extending downward to 
 the proximal border of the scapular cartilage, 
 where they find another fixed attachment. It 
 is fused with and in fact may be regarded a 
 part of the superficial fascia. As a structure 
 to incise for invasions into the withers it may 
 be so considered. Beneath the superficial fas- 
 cia is another aponeurotic layer whose fibers 
 are so arranged as to cross those of the tra- 
 pezius beneath at right angles. This layer is 
 of no special surgical importance. It is found 
 only in a careful dissection of the region and is 
 in no way influential in guiding pathological 
 processes nor in shaping surgical procedure. 
 
 The Trapezius 
 
 The trapezius, excluding the fascia just 
 mentioned, is the third layer of the withers and 
 is really the first of the anatomical structures 
 that must be reckoned with in the study of fis- 
 tula. It is a triangular membranous muscle 
 with its base upward running along the withers 
 where its aponeurosis is attached to the supra- 
 spinous ligament along the withers and to the 
 ligamentum nuchse in the cervical region, ex- 
 tending in all from the axis to the tenth dorsal 
 vertebra. This triangidar sheet-like structure 
 
18 FISTULA AND POLL-EVIL 
 
 is bisected vertically with a central aponeurosis 
 that is attached ventrally to the tuber spinse of 
 the scapula. The anterior part is the trapezius 
 cervicalis and the posterior the trapezius thora- 
 calis. 
 
 The Roof of the Withers 
 
 Together with the skin, the fascia arid the 
 panniculus carnosis, the trapezius muscles may 
 he regarded as the 'Woof of the withers'' 
 
 It is under this roof that typical fistula of 
 the withers develop and beneath which the 
 atypical (traumatic) fistulge burrow in direc- 
 tions of resistance less than that afforded by 
 its dense, aponeurotic character. 
 
 Rhomboideus Thoracalis 
 
 The rhomboideus thoracalis extends from 
 the spinous processes of the second, third, 
 fourth, fifth, sixth and seventh dorsal verte- 
 brae in a downward and outward direction to 
 the mesial face of the scapular cartilage. It 
 constitutes a thick, heavy curtain forming a 
 "second or inner roof of the withers." Com- 
 pared with the structures of a building, it 
 might be said to be a curtain, sagging slightly 
 in the middle, that extends from the comb of 
 the roof to a point on the wall just beneath the 
 plate beam. It is very loosely attached to the 
 
THE WITHERS 19 
 
 mesial face of the trapezius laterally and to the 
 longissimus dorsi ventrally and spinalis dorsi 
 mesially and ventrally. Secondary abscesses 
 of fistul^e of the withers said to be located "un- 
 der the scapula" are in reality located under 
 this muscle, resting upon the longissimus dorsi 
 but without any obstacle against the filtration 
 of pus further down than under the upper part 
 of the serratus dorsi. Pus seldom goes to a 
 lower level because the latter muscle is at- 
 tached firmly to the costal surface and above to 
 the mesial face of the scapula, forming a space 
 having a firm floor but without anterior and 
 posterior walls. 
 
 Rhomboideus Cervicalis 
 
 The rhomboideus cervicalis is the forward 
 elongation of the thoracalis, extending toward 
 the head along the ligamentum nuchse as far 
 forward as the axis. Its insertion is the an- 
 terior part of the mesial face of the cartilage of 
 prolongation. Its surgical importance lies in 
 the fact that its ventral margin just in front of 
 the scapula affords a point of invasion into the 
 seat of a typical fistula (Fig. 2). It is also so 
 closely related to the ligamentum nuchcT that 
 it seldom escapes attack from the morbid pro- 
 cess, and when heedlessly sacrificed in resect- 
 ing the ligamentum nucha? a pronounced de- 
 
20 FISTULA AND POLL-EVIL 
 
 formation of the crest of the neck (ewe-neck) 
 results. It may be said to reinforce the "roof 
 of the withers" anteriorly. 
 
 Other Structures Important Surgically 
 
 The splenius and the serratus cervicis are 
 related to, in fact occupy, the anterior part of 
 the withers. They lie immediately below the 
 rhomboideus cervicalis and beneath the trap- 
 ezius cervicalis. Their upper margins are re- 
 lated to the former. Just in front of the car- 
 tilage of prolongation they are very looseh^ 
 attached to the rhomboideus and thus afford 
 the portal for surgical invasion above referred 
 to: They are thick, tuberous curtain-like mus- 
 cles forming the bulk of the crest of the neck 
 and on account of their thickness prevent 
 facile direct invasion to the bottom of pus ca- 
 vities which are usually located below this mar- 
 gin at the level of the second dorsal spine. 
 These two thick muscles, in short, form the 
 lower part of the lateral walls of the pus cav- 
 ity in fistula of the withers. The treatment of 
 fistula of the w^ithers would be a lesser problem 
 if the pus cavity could be drained over the dor- 
 sal margin of these muscles instead of through 
 them. 
 
 The longissimus dorsi. The longissimus dorsi 
 at the withers occupies the space between the 
 
THE WITHERS 21 
 
 rhomboideus and the complexus and spinatus. 
 These three muscles may be said for descrip- 
 tive purposes to fill in the angular space 
 formed by the ribs and vertebral spines. 
 
 Structures of Lesser Surgical Importance 
 
 The complexus anteriorly and the spinalis 
 dorsi posteriorly have no especial surgical sig- 
 nificance, except that the former lies closely 
 attached both to the lamellar and the funicu- 
 lar 23ortions of the ligamentum nuch^ and the 
 latter to the spines of the vertebra and are 
 therefore implicated in disease processes, and 
 besides being just two more structures to form 
 channels for the burrowing of pus they in no 
 way govern the course of surgical operations. 
 In fact pus cavities that have formed beneath 
 these muscles are inaccessible and disease of 
 the structures between them (bones posteriorly 
 and the lamellar portion of the ligamentum 
 nuchas anteriorly) usually constitutes an in- 
 curable condition. 
 
 Viewed as a Whole 
 
 The muscles of the withers viewed with the 
 purpose of standardizing surgical procedure 
 against fistula may be compared to an irregu- 
 larly-shaped covered trough containing a 
 longitudinal partition. Anteriorly the trough 
 is walled by the splenius and the serratus cer- 
 
22 FISTULA AND POLL-EVIL 
 
 vicis, posteriorly by the serratus thoracis and 
 the scapular cartilage. Its floor is formed by 
 the longissimiis dorsi and its roof by the trap- 
 ezius and rhomboideus. The central partition 
 is constituted of the dorsal spines, spinalis dorsi 
 posteriorly and the lamellar portion of the 
 ligamentum nuchse covered with the com- 
 plexus anteriorly. The bottom of the trough 
 which must be reached for effectual drainage 
 can be penetrated only with difficulty and the 
 risk of inviting complications in structures not 
 previously implicated. Furthermore, these 
 muscles being in constant use in locomotion, 
 respiratory acts and movements of the neck, 
 tend to encourage the burrowing of pus into 
 still more inaccessible recesses. 
 
 Thus we find the musculature of primal im- 
 portance in any study of fistula of the withers. 
 It bounds initial abscess cavities in places 
 difficult of access for drainage, they move upon 
 each other and favor the distribution of puru- 
 lent products into new fields, where secondary 
 abscesses are formed, and it exhibits a remark- 
 able trend toward fibrosis under the influence 
 of the chronic inflammation of adjacent parts. 
 
 The Ligaments 
 
 The ligaments implicated in fistula of the 
 withers are the ligamentum nuch^e and the 
 
THE WITHERS 23 
 
 supraspinous ligament, each of which is but a 
 continuation of the other; the dorsoscapular; 
 and the interspinous hgaments, which curtain 
 off the spaces between the spinous processes. 
 
 The hgamentum nuchge is a strong, powerful 
 apparatus conij)osed of yellow elastic tissue and 
 divided into two distinct parts: the funicular 
 portion and the lamellar portion. The former 
 which is of especial importance in fistula of the 
 withers and poll-evil, extends from the occip- 
 ital bone anteriorly to the summit of the 
 withers posteriorly where it becomes white 
 fibrous tissue and is continued over the spines 
 of the sacrum as the posterior part of the sup- 
 raspinous ligament. It is composed of two 
 lateral halves each of which is heavy and 
 flattened at the withers but gradually becom- 
 ing round and somewhat smaller toward the 
 occipital crest to w^hich it is attached to the 
 occipital protuberance. Two bursge are 
 found associated with this structure — one 
 at the atlas and the other in the dorsal region. 
 The atlantal bursa is the seat of poll-evil while 
 the dorsal or supraspinous bursa is the location 
 of typical fistula of the withers. The atlantal 
 lies between the ligament and the dorsal sur- 
 face of the atlas. Tlie dorsal bursa is usually 
 over the third dorsal spine but sometimes ex- 
 tends backward as far as the crest, that is, over 
 
24 FISTULA AND POLL-EVIL 
 
 the fourth and the fifth spines, and often as 
 far forward as the second. It is at the level of 
 the second dorsal spine where the causative 
 center of most of the cases of fistula of the 
 withers that we have examined carefully, were 
 located. 
 
 An important point to remember about the 
 funicular portion of the ligamentum nuchas is 
 its wide expansion posteriorly. Approaching 
 the crest of the withers it extends in the out- 
 ward and downward direction five to six inches, 
 partly enveloping the rhomboideus and tra- 
 pezius. This expanded portion is often the 
 cause of recurrence of fistula after the main 
 portion has been removed. 
 
 It is surmounted along its course by the 
 "pad of the mane" a structure composed of 
 elastic fibers interspersed with adipose tissue. 
 It is most abundant in the middle of the cervi- 
 cal region and is best developed in stallions of 
 the draft breeds. 
 
 The funicular portion is a sheet-like par- 
 tition dividing the superior cervical muscles 
 into halves. It is composed of two layers 
 attached loosely to one another by areolar tis- 
 sue, and each layer is composed of two parts, 
 anterior and posterior. The anterior part is 
 thick and strong, attached to the funicular 
 portion above and to the cervical spinous proc- 
 
THE WITHERS 
 
 25 
 
 .^< 
 
 ;f% 
 
 ^, X W 
 
 .h 
 
 .r 
 
 H' 
 
 Pig. 1— Ligamentum Nuche of Horse. 
 Note particularly the relation of the funicular portion of 
 the ligamentum nuche to the atlas and to the spines of the 
 thoracic vertebrae. Also the arrangement of the lamellar 
 portion. (After Sisson.) 
 
26 FISTULA AND POLL-EVIL 
 
 esses below. The posterior part is attached to 
 the second and third dorsal spines and extends 
 in the form of several digitations forward and 
 downward where its brush-like fibers reach the 
 spines of the fifth and sixth cervical segments. 
 The fibers of the ligament are more spare than 
 in the anterior part and sometimes do not even 
 reach the sixth vertebra. Between the anterior 
 and the posterior parts is a space of consider- 
 able dimensions which especialh^ in horses of 
 good flesh contains a mass of fatty tissue. This 
 opening is at the level of the extremity of the 
 second dorsal spinous process and is the seat 
 of typical fistula of the withers. It is the space 
 where the sacculation of fistula begins. 
 
 The supraspinous ligament is a structure 
 composed of white fibrous tissue and extends 
 along the dorsal region to the sacrum. It is 
 the continuation of the ligamentum nucha? 
 posteriorly. A careful dissection of this struc- 
 ture fails to show^ that it begins as an independ- 
 ent structure, as its fibers although they change 
 in structure from yellow elastic to white fibrous 
 tissue, are simply continuations of each other. 
 From the surgical standpoint the supraspinous 
 Hgament and the ligamentum nuchge must be 
 regarded as a single apparatus which changes 
 in the character of its tissue at the crest of the 
 withers. Over the crest it is a verv thick, dense 
 
THE WITHERS 27 
 
 structure and along its whole course backward 
 it is attached firmly to the summits of the 
 spines. 
 
 The interspinous ligaments are thin mem- 
 branous structures connecting the spines to one 
 another and completely filling in the space 
 between them from the bodies to the supraspi- 
 nous ligament above, and thus completing a 
 perfect partition between the two halves of the 
 withers 
 
 The dorso-scaj)ular ligament is a reflection 
 of the superficial fascia. It is a thick aponeu- 
 rosis attached dorsally to the crest of the 
 withers and passing outward and downward 
 under the rhomboideus to the scapula and 
 giving off layers which pass between the under- 
 lying muscles — the longissimus and spinalis. 
 At the crest it is really the aponeurotic origin 
 of both the rhomboideus thoracalis and the 
 splenius. 
 
 The importance of these ligaments in fistula 
 of the withers lies in the fact that they are 
 implicated in the disease more commonly than 
 the other component parts. Lying adjacent to 
 the initial seat of the inflammatory process, 
 and being but poorly nourished structures, they 
 fall an easy prey to microbic products, becom- 
 ing riddled with necrotic areas and thus pre- 
 venting cicatrization of contiguous abscess 
 
28 FISTULA AND POLL-EVIL 
 
 cavities. In poll-evil it is the anterior part of 
 the funicular portion of the ligamentum 
 nuchge that prevents healing, while in fistula 
 of the withers it is the posterior end or its liga- 
 mentous continuation — the supraspinous liga- 
 ment — that is implicated. 
 
 Cartilsiges of the Withers 
 
 The cartilaginous tissue included among the 
 component parts of the withers is found in the 
 scaj)ular cartilage (cartilage of prolongation) 
 and in the semi-cartilaginous summits of the 
 dorsal spines. 
 
 The scapular cartilage which is attached to 
 the vertebral border of the scapula is a wide 
 expanse of hyaline cartilage about two inches 
 wide extending from the cervical to the dorsal 
 angle. It is thick at the attachment to the 
 bone but becomes thin toward its vertebral 
 border which presents an evenly rounded pro- 
 file. Its mesial relations are the rhomboideus 
 and the serratus ventralis and its lateral the 
 trapezius and the attachment of the panniculus 
 carnosis. To these muscles it is intimately 
 related, being in fact imbedded in them. It 
 forms the lateral wall of many of the secondary 
 abscesses of fistula and its cervical angle and 
 sometimes its vertebral border becomes impli- 
 cated in the disease. By becoming divested of 
 
THE WITHERS 29 
 
 its muscular attachments and perichondrium it 
 plays the role of a foreign body and thus per- 
 petuates secondary fistulous tracts, which, on 
 account of the movement to and fro are very 
 slow to cicatrize, even after the necrotic parts 
 have been extirpated. 
 
 Cartilage is found on the spinous processes 
 of the third, fourth, fifth, sixth and seventh 
 spines, but is most abundant on the fifth and 
 sixth. To this cartilage is fused the fibers of 
 the supraspinous ligament. When the liga- 
 ment detaches from disease the cartilaginous 
 ends lie bare and being soft often induce sur- 
 geons to indulge in reckless curetting when no 
 such procedure is indicated. Protruding like 
 stumps into the bottom of the abscess cavity 
 and being slow to separate from the viable 
 bone beneath, these cartilaginous summits are 
 exceedingly instrumental in delaying cicatriza- 
 tion and a prolific source of recurrences. 
 
 Bones 
 
 The bones of the withers are the spinous 
 processes of the dorsal vertebra from the sec- 
 ond to the point posteriorly where they reach 
 the level of the back. They incline backward. 
 They are thin at the anterior border, thick 
 posteriorly and expanded dorsally to receive 
 the attachment of the supraspinous ligament. 
 
30 FISTULA AND POLL-EVIL 
 
 They increase in length from the first to the 
 crest (the fifth) and then gradually diminish 
 to the twelfth. Those immediately over the 
 crest exhibit the cartilaginous ends above men- 
 tioned. The increase in length is not symmet- 
 rical, the second being almost twice as long as 
 the first. 
 
 They are connected to one another by the 
 interspinous ligaments which complete an im- 
 pervious partition between the two lateral 
 halves of the withers. Laterally they are cov- 
 ered with the spinalis and longissimus dorsi 
 muscles. 
 
 The spinous processes rank high in impor- 
 tance in the study of fistula of the withers. The 
 initial pathological jDrocess of typical fistula is 
 usually seated on the second and third seg- 
 ments. The cyst which constitutes the first 
 pathological change is attached to them and 
 when opened often exposes their cartilaginous 
 summits. In traumatic fistula originating 
 from superficial wounds, these processes often 
 become the seat of a stubborn osteitis that 
 descends into the cancellated tissue, sometimes 
 as far down as the bodies of the vertebra, 
 creating very chronic if not always incurable 
 conditions. 
 
 The student of surgical anatomy should 
 remember their length at the different points, 
 
THE WITHERS 31 
 
 their cartilaginous summits, their backward 
 direction, their connecting media and the con- 
 tiguous musculature. 
 
 Blood Vessels 
 
 The withers receives its blood supply chiefly 
 from two sources: the dorsal and the deep 
 cervical arteries. Both are direct radicals of 
 the brachial arteries, or more correctly speak- 
 ing, the left one arises from the left brachial 
 artery and the right one from that part of the 
 same vessel on the right side while it still bears 
 the name brachiocephalic artery. The origin 
 of both is within the thorax. The dorsal 
 enters the region of the withers through the 
 second intercostal space and the deep cervical, 
 through the first. Both of them leave the 
 thorax near the bodies of the vertebrae. Their 
 extra- thoracic distribution alone interests us, 
 in surgery of the withers. 
 
 Ecctra-tlioi'acic distiihution of the dorsal 
 artery. After emerging from the thorax 
 through the second intercostal space it passes 
 under the longissimus dorsi in an upward and 
 backward direction, soon dividing into several 
 branches. The largest anterior branch passes 
 forward and upward under the splenius; 
 extending branches anastomose with the deep 
 cervical or are lost in the deep muscles of 
 
32 FISTULA AND POLL-EVIL 
 
 the cervical region. The posterior branches 
 pass upward between the dorso-seapiilar Hga- 
 ment and the rhomboideus and thence to the 
 snperficial mnscles and skin. These radicals 
 are normally small vessels, bnt in old fistula 
 they are often enlarged into arteries of a 
 formidable capacity. The main trunk lying 
 deeply in the base of the withers is seldom 
 exposed in surgical operations. The variation 
 in the distribution of these branches and 
 especially the enlargement of some of them 
 under the influence of disease make the study 
 of the blood supply of the withers somewhat 
 unsatisfactory from the surgical standpoint. 
 There is always a pronounced difference in the 
 amount of bleeding produced from incisions 
 of exactly the same kind. 
 
 The eoctra'tJioracic distiihution of the deep 
 cervical artery. — Emerging from the fiist 
 intercostal space, it passes upward and for- 
 ward between the lamellar portion of the 
 ligamentum nuchge and the complexus. It 
 destination is the region of the poll where it 
 anastomoses with branches of the occipital. 
 Along its course along the neck it exhibits free 
 commimications with the vertebral and sup- 
 plies by lateral branches the lateral cervical 
 muscles. These lateral branches of the deep 
 cervical which enter the splenitis and serratus 
 
THE WITHERS 
 
 33 
 
 Fig. 2. — Deep Dissection of Neck of Horse. 
 A. Deep Cervical Artery. (After Sisson.) 
 
84 FISTULA AND POLL-EVIL 
 
 cervicis in the region of fistula of the 
 withers are often enlarged into vessels of con- 
 siderable dimensions. 
 
 The vertebral artery, — The vertebral artery 
 which emerges from the thorax in front of the 
 first rib passes between the longus colli and 
 the scalenus, and thence along the vertebral 
 column through the foramina transversaria. At 
 the axis it anastomoses with the occipital and 
 along its course supplies numerous branches 
 to the musculature, of both the dorsal and 
 ventral cervical regions. The former anasto- 
 moses freely with branches of the deep cervical. 
 
 This artery is of no great importance in 
 surgery of the withers on account of its deep, 
 protected location. That its branches are 
 capable of undergoing enlargement must, 
 however, be considered in operations invading 
 the region of the vertebral column, as for 
 example in attempts to establish a drainage 
 of abscess cavities resting on the bodies of the 
 vertebrae (cervical fistula). 
 
 The Nerves 
 The nerves of the withers are both cranial 
 and spinal. Sensation is supplied by the dor- 
 sal branches of the thoracic and cervical spinal 
 nerves while the motor supply is derived not 
 only from those mixed nerves but also from 
 
THE WITHERS 36 
 
 the spinal accessory — the eleventh cranial — 
 nerve. 
 
 The spinal nerves are seldom exposed to 
 view in surgery of the withers and as they have 
 a promiscuous distribution, loss of motor 
 power is never observed from incision of the 
 trunks or their ramuli. 
 
 The spinal accessory being the chief motor 
 supply of the trapezius and lying in a super- 
 ficial position may be incised in making reck- 
 less vertical incision over the lateral surface 
 of the scapula below the scapular cartilage. 
 Its division while not attended with any pro- 
 nounced harm is inadvisable on the general 
 grounds that large muscular areas should not 
 be unnerved. 
 
 The Lymphatic Systein of the Withers 
 
 This may be said to include the intercostal 
 nodes of this region and the prescapular nodes, 
 together with their afferent vessels. 
 
 The intercostal nodes are located at the 
 intercostal spaces at each side of the vertebrae, 
 and they receive vessels arising chiefly in and 
 among the dorsal muscles. They are small in 
 the normal state but in fistula of the withers 
 they become larger and may even suppurate or 
 become the initial seat of a secondary pleuritis, 
 
36 FISTULA AND POLL-EVIL 
 
 The afferent vessels empty directly into the 
 thoracic duct. 
 
 The prescapidar glands receive afferent ves- 
 sels from the skin of the anterior part of the 
 withers and also from the superficial muscles 
 of the neck. The afferent vessels lead to the 
 posterior cervical nodes and thence to the tho- 
 racic duct. 
 
PATHOGENESIS 
 
 There are two kinds of fistulce of the 
 withers. One is the tijpical or idiopathic form 
 and the other is the atypical, traumatic or 
 symptomatic form. The first or typical has its 
 origin in the development of a serous sac or 
 cyst under the ligamentum nuch« at the level 
 of the second or third dorsal spines, while the 
 second or atypical is caused by an external 
 wound that serves as a portal of entrance for 
 microorganisms. In the first stages these tw^o 
 forms differ very materially in every respect 
 but in the final stage they are alike in that both 
 of them cause disease of the ligamentum 
 nuch« or its backward extension (the supra- 
 spinous ligament) and sometimes the spines of 
 the vertebra themselves. In short, each form 
 finally plays the same havoc upon these struc- 
 tures, although they have an entirely different 
 pathology at the beginning. Fistula of the 
 withers in the final stage might be properly 
 called necrosis of the ligamentum nuchae or of 
 the supraspinous ligament according to its 
 cephalo-caudal location. In the typical form 
 it is the ligamentum nuchae that is chiefly 
 affected while the traumatic form, being 
 
38 FISTULA AND POLL-EVIL 
 
 usually due to harness bruises, reflects more 
 upon that part of the region occupied by the 
 supraspinous ligament. The disease pro- 
 gresses in many cases from one to the other of 
 these two structures by extension of the dis- 
 ease process in one direction or the other 
 according to the initial seat. That is to say, a 
 fistula beginning in a cyst at the level of the 
 second dorsal spine may attack the liga- 
 mentum nucha above that level and then 
 travel backward into the supraspinous liga- 
 ment, while on the other hand a harness bruise 
 may cause a disease of the supraspinous liga- 
 ment at the level of the saddle seat that will 
 travel forward into the ligamentum nuchge. 
 In fact, all old cases have this dual involvement 
 and often the spines beneath are found necrotic. 
 
 The Typical Form 
 
 To make our study more comprehensive we 
 shall divide the development of this form of 
 fistula into three stages, namely: The saccu- 
 lar stage, the phlegmonous stage and the 
 fistulous stage. 
 
 1. Saccular Stage. This is the initial one. It 
 has its origin in the accumulation of serosity 
 upon or adjacent to one of the dorsal spines, 
 usually the second. Beginning with this col- 
 lection of serum, which is sero-fibrinous in 
 
PATHOGENESIS 39 
 
 character, it gradually enlarges into a cyst of 
 larger and larger dimensions until it becomes 
 clinical by bulging at the surface of the base 
 of the neck or at a point of least resistance 
 adjacent thereto. The sac is at first very small 
 and without any well developed limiting mem- 
 brane but as it becomes larger the tissues react 
 to the encroachment by forming a firm con- 
 nective tissue layer around it and at the same 
 time fibrin and cells attach themselves to the 
 inner wall and thus pave it with a smooth 
 carpet that completes a firm encapsulation of 
 the liquid contents. The amount of connective 
 tissue contained in the encapsulating structure 
 varies with the chronicity of the process. In 
 old, slotdy forming cases the fibrous elements 
 may form in large quantities, encroaching upon 
 the capacity of the sac internally and gradually 
 bulging exteriorly until the lesion is in fact 
 more fibrous than cystic. Thus ice have the 
 large fistulae of the icithcrs in tchich fibrosis is 
 the dominating feature. This sac is uniformly 
 related to one of the dorsal spines, usually the 
 second, but sometimes the third and in rare 
 cases the fourth or even the fifth. We have 
 never seen a typical fistula of the withers orig- 
 inate farther back. Those located on the sum- 
 mit or further back are always of the other 
 variety (traumatic or atypical). The point of 
 
40 FISTULA AND POLL-EVIL 
 
 predilection of typical fistula of the withers is 
 stubbornly anterior to the summit of the 
 withers — in the space where tlie spines decline 
 abruptly into the cervical region. 
 
 The sac forms slowly and without apparent 
 pain or discomfort to the patient. We have 
 found ample evidence post-mortem in subjects 
 that have died from other causes that cysts of 
 this character sojourn here without attracting 
 attention. They are too small to bulge ex- 
 ternally and cause no distress that would at- 
 tract one's attention to them. These hidden 
 cysts are sometimes the size of an egg and 
 sometimes as large as a base ball, and when 
 old are so well encapsulated as to prevent fur- 
 ther development. Thus cysts may never de- 
 velop into fistuhe or, in other words, the sac- 
 cular stage may never advance into the fis- 
 tulous stage. The process is arrested by 
 encapsulation and later the fluid content is re- 
 abs()r})ed, leaving no trace of its previous ex- 
 istence. The resulting cicatrical tissue is lost 
 in its connective environment. This process of 
 arrested develojnnent, encapsulation and reab- 
 sorpfion occurs also in clinical cases. Or in 
 other words, a clinical case of fistula of the 
 withers in tlie saccular stage tliat has never 
 been exposed to extraneous microorganisms 
 may disappear spontaneously. It is tlius that 
 
PATHOGENESIS 41 
 
 liniments and blisters applied to them often 
 are credited with curative properties when, in 
 fact, it was an inherent influence that operated 
 to that end. 
 
 The duration of this stage has been very 
 difficult for us to determine. We believe, how- 
 ever, that it is very irregular, that some cases 
 develop very rapidly into clinical cases while 
 others remain almost dormant for months, 
 some disappearing entirely and some bulging 
 slowly toward the surface. 
 
 It is these slowly forming ones that develop 
 so much fibrous tissue and thus change the en- 
 tire aspect of the condition from cyst to neo- 
 plasm. This occurrence seems almost sufficient 
 reason to include in the classification a third 
 form of fistula of the withers — the fibrous 
 form — if the reader were not familiar with the 
 remarkable aptitude of horse-flesh to form 
 fibrous tissue from continued irritation. 
 Edema, pressure, foreign body, feebly virulent 
 infection, cold abscess, granuloma and other 
 tumors in the flesh of horses cause the forma- 
 tion of great volumes of fibrous tissue luilike 
 that of any other animal. It is thus that a 
 slowly forming fistula beginning in the depths 
 of the neck becomes the underlying cause of 
 the formation of new tissue in such abundance 
 
42 IISTULA AND POLL-EVIL 
 
 as is seen in some cases of fistula long before 
 infection has entered into the situation. 
 
 Sunimarizing the condition during the sac- 
 cular stage we find a sac containing a sero- 
 fibrinous, sterile exudate, that may be large 
 and surrounded by a thin capsule or small and 
 enclosed in a very thick mass of connective tis- 
 sue. Between these two extremes we find the 
 intermediate varieties — for example, one the 
 size of a child's head containing a quart of 
 fluid and encapsulated with a fibrous envelope 
 one incli in thickness ; another the size of a foot- 
 ball with only a very thin wall; and finally, a 
 rare case with a very insignificant cavity sur- 
 rounded with a great volume of connective 
 tissue. Pathologically all of these are similar, 
 they differ only in the relative quantities of 
 the different elements entering into their con- 
 stituent parts. 
 
 During this stage fistula is a benign disease. 
 It is not as yet infectious. There is no syste- 
 matic disorder. The patient suffers no appar- 
 ent inconvenience. Its general health is 
 undisturbed. 
 
 Until now the process belongs to an order of 
 pathological conditions no more understood 
 than the growth of tumors. In fact, it re- 
 sem])les tumor and cyst formation in all 
 respects. It is but cellular activity around a 
 
PATHOGENESIS 43 
 
 fluid-containing cavity with the formation of 
 new tissue influenced by an unknown stimulus. 
 Henceforth, however, a change occurs; it 
 passes into another entirely different stage 
 through the intrusion of pyogenic microor- 
 ganisms into the cavity. 
 
 2. Phlegmonous Stage, This is the second 
 step in the development toward a real fistulous 
 condition. Inasmuch as there is no positive in- 
 formation about the thoroughfare through 
 which infection occurs we shall only venture an 
 opinion that it is through the blood stream or 
 lymph channels that the microbes reach their 
 goal. There is, of course, the possibility that 
 cutaneous bruises from the collar may afford 
 an entrance avenue, but the fact that suppura- 
 tion occurs in animals that have never been in 
 harness and could not reasonably have sus- 
 tained contusions of sufficient severity to cause 
 subcutaneous infection, least of all, a still 
 deeper infection within the cavity without any 
 surface inflammation, leaves no doubt that at 
 least a great majority of fistulas become in- 
 fected fi^om witJiin. We have observed fistulee 
 develop rapidly from the saccular to the phleg- 
 monous stage following influenza, especially 
 complicated influenza. In fact, fistula of the 
 withers might with all reason be included as 
 one of the sequelae of influenza. The large 
 
44 FISTULA AND POLL-EVIL 
 
 number of remounts that develop this compli- 
 cation after attacks of shipping fever confirms 
 our observation of twenty-five years of city 
 practice in this connection. The saccula?' stage 
 of the disease affords a fertile field for the 
 localization of the microbes in the germ-ridden 
 hodji of the influenza patient. 
 
 Once infected the patient falls sick and is 
 henceforth in the siege of an enfeebling disease. 
 The temperature rises to 102 degrees to 104 
 degrees Fahrenheit; depression is pronounced 
 and movements of the body are painful. Often 
 the patient grunts as in pleurisy from the pain 
 of turning the body. When these symptoms 
 occur before there is any conspicuous surface 
 swelling, there is indeed danger of overlooking 
 the cause of the patient's indisposition. Or- 
 dinarily the withers are hot, tumefied, radiating 
 and painful on one or both sides. 
 
 The course of this stage will depend upon 
 the virulence of the infection, the fertility of 
 the field afforded by the saccular stage, and the 
 natural resistance of the patient. If the sac is 
 small and well encapsulated and the infection 
 feebly virulent, the process may be slow and 
 even go on almost unnoticed, all of tlie while 
 causing the formation of more fibrous tissue 
 and making its inroad of destruction into the 
 ])()()rly nourislied hgamentum nuclut and ad- 
 
PATHOGENESIS 45 
 
 jacent structures, coming to the surface very 
 slowly. It is, in fact, a cold abscess. Some 
 months may elapse after infection has occurred 
 before the abscess points at the surface, but all 
 of the while ^pathological changes are taking 
 place within. JMore connective tissue is formed 
 and the necrosis of the ligament is extending 
 forward and backward from the seat of the 
 abscess which was originally the cyst. Soaked 
 in this infected environment the dorsal spines 
 become involved and sej^arate from the soft 
 structures attached to them, sometimes stand- 
 ing out stump-like into the cavity until seques- 
 tration occurs. Slowly the pus finds an exit 
 at the surface of the body after burrowing here 
 and there in different directions. The exit 
 aperture is not uniformly located. It may 
 sometimes appear at the summit of the enlarge- 
 ment, but more often it is more remote, the pus 
 having traveled between the different layers of 
 fascia and muscular tissue of this complex- 
 region to places far removed from the initial 
 hot-bed. We once traced a fistulous tract from 
 the lumbar region forward along the longissi- 
 mus dorsi, under the scapula to the level of the 
 second dorsal vertebra. Other cases burrow 
 backward under the cervical angle of the scap- 
 [da and point at tlie highest point of the withers, 
 leaving one to suppose that this is the original 
 
46 FISTULA AND POLL-EVIL 
 
 seat of the trouble as in the traumatic forms. 
 This hkelihood of fistulas to point at or near 
 one side of the summit has misled many a prac- 
 titioner away from the actual seat of the causa- 
 tive center. In short, the existence of the aper- 
 ture in a posterior location is no indication 
 that the case is not a typical one centered at 
 the usual place, under the ligament at the level 
 of the second dorsal spine. The aperture may 
 come at different very remote points that are 
 often deceptive. 
 
 The average case is more acute. Given one 
 with a sac containing a quart of fluid with a thin 
 capsule and infected with virulent microbes 
 that produce an acute inflammatory process, a 
 channel is soon dissolved directly to the surface. 
 Often pointing occurs long before there is much 
 damage done to either the ligament and bones 
 and if proper treatment were instituted, these 
 might never become seriously involved. A cure 
 could be effected without disturbing them. The 
 cyst is developed, becomes infected and bursts 
 at the surface without having done much dam- 
 age. This is the most favorable of all the 
 fistulae of the withers to treat surgicall}^ On 
 the contrary, if the process is slow and there 
 is delay in pointing, and if no treatment is 
 instituted to relieve matters, the disease slowly 
 but surely encroaches into the adjacent struc- 
 
PATHOGENESIS 47 
 
 tures and thus creates a less favorable con- 
 dition. 
 
 The duration of this stage Hke the former 
 one is variable. If the infection is acute and the 
 cyst wall thin, the abscess may ripen and burst 
 in a few days, while on the other hand if less 
 virulent and incarcerated in a thick wall, point- 
 ing may be delayed for weeks and even months. 
 When the abscess has once found a surface 
 exit and has discharged its contents, the disease 
 has passed into an entirely different stage, and 
 for a time the systemic condition improves. 
 
 3. Fistulous Stage. This is fistula of the 
 withers. Heretofore the condition was fistula 
 only in name, now it is a reality. Heretofore 
 the course of the disease was guided solely by 
 internal influences, now it is exposed also to 
 secondary infections from without. It does not 
 matter whether the pointing was spontaneous 
 or whether an aperture was made artificially, 
 we now have to deal with a deep-seated cavity 
 that communicates freely with the outside 
 where reinfection will continue to occur, and to 
 make matters still worse the drainage is seldom 
 good enough to evacuate the contents entirely. 
 By remaining full of pus the cavity becomes a 
 fertile field for microbian growth and cicatrizes 
 very slowly. The pus-soaked walls of the cav- 
 ity becoming carpeted with undulating indol- 
 
18 FISTULA AND POLL-EVIL 
 
 ent granulations that encroach slowly on its ca- 
 2)acity and without always showing any ten- 
 dency to complete the process of cicatrization 
 hecause they must sprout largely from a poorly 
 nourished matrix (the ligament) which now 
 dies in foci here and there, and then sojourns 
 only as a foreign agent to ])erpetuate the 
 process indefinitely. The ligament, contrary 
 to the generally accepted conclusion, is never 
 found entirely dead, except in very old and ex- 
 ceptional cases; it undergoes only focal 
 necrosis at different spots, retaining enough 
 vitality to delay sequestration, and all of the 
 while sprouting out with indolent granulations 
 over its viable zones. The granulations are in- 
 capable of maturing into scar tissue because of 
 the dead zones protruding here and there 
 among them and because they are poorly nour- 
 ished. Thus we must not suppose when w^e say 
 that fistula of the withers is due to necrosis of 
 the ligamentum nuch^, that the ligament is 
 immediately dead and that as a dead object 
 perpetuates the disease right from the begin- 
 ning. Fistula on the contrary is due to the slow^- 
 ly dying process of the ligament, to its stub- 
 born viability rather than to its death. Once 
 dead, however, and separated from the living 
 part, the cavity w^ill cicatrize as soon as the 
 slough is removed, encysted or dissolved, pro- 
 
PATHOGENESIS 49 
 
 viding there are no secondary cavities that do 
 not drain. 
 
 During the fistulous stage of the disease we 
 must reckon, therefore, with a slowly dying 
 ligament, exfoliation of the ends of the spines, 
 the secondary pus due to the burrowing of pus 
 into adjacent spaces and the fibrosis that con- 
 tinues to encroach upon the surrounding mus- 
 culature. It is plain that these constitute a 
 combination of very inimical conditions. There 
 is also in addition to these, a chronic septicemia 
 that slowly but siu'ely undermines the general 
 health and manifestly reduces the patient's 
 vitality. The tracts leading from pus cavities 
 to the surface apertures, to still further com- 
 plicate matters, close up by cicatrization from 
 time to time and thus pen up the pus again until 
 it has burrowed out a new channel. During 
 this occurrence the patient is again sick as in 
 the phlegmonous stage, exhibiting pain, dis- 
 tress in movement, fever and general malaise. 
 Each attack of this kind leaves the patient more 
 enfeebled and still further damages the withers 
 by forming new tracts, more fibrous tissue and 
 sometimes new secondary cavities. The disease 
 ends in one of two ways: the common one is 
 emaciation and death, and the other is chronic 
 fistula, discharging limited amounts of pus for 
 several years. Rare cases heal up spontan- 
 
50 FISTULA AND POLL-EVIL 
 
 eously. Often the death follows an operation 
 postponed too long, postponed until the patient 
 is too weak to stand the ordeal of the extensive 
 intervention needed to cope with the neglected 
 condition. 
 
 The location of the secondary pus cavities is 
 varied. Backward between the scapular car- 
 tilage and the dorsal spines as far back as the 
 caudal angle of the scapula and under the 
 rhomboideus, is a favorite location. Another 
 place where pus commonly gathers is in the 
 space under the scapula just above the insertion 
 of the serratus thoracalis, and sometimes this 
 same cavity is diverted also under this muscle 
 and then extends downward over the costal sur- 
 face as far down as the sternum. The most 
 serious secondary cavity, however, is the one 
 that seats itself in the cervical region on the 
 bodies of the vertebrae on one or both sides of 
 the lamellar portion of the ligamentum nucha^, 
 This one constitutes what has been called cervi- 
 cal fistula, a condition due to implication of the 
 ligament anteriorly. When a large area of the 
 lamellar portion is involved the neck tumefies 
 on both sides and one or more tracts form to 
 the surface, often as far forward as the middle 
 third of the cervical region. This is one of the 
 most hopeless terminations of fistula of the 
 witliers as the affected center is inaccessible to 
 
Fig. 3. — A Pro-nounced Fistula of the Withers. 
 
52 FISTULA AND POLL-EVIL 
 
 any form of effectual treatment. The affected 
 area of ligament is too extensive to extirpate 
 and drainage apertures cannot be made nor 
 maintained to any advantage. In short, 
 cervical fistula is an incurable, hopeless con- 
 dition. 
 
 Still another location is the bodies of the 
 dorsal vertebrae between the scapulae. Here 
 the pus follows the spines downward and seats 
 itself at an inaccessible place for drainage. 
 
 The Atypical Form 
 
 By atypical fistula we refer to those of 
 strictly traumatic origin. They supervene 
 saddle, harness and collar sores and cutaneous 
 contusions of various kinds, especially those 
 due to a hard, continuous pressure or deep 
 pressure. Most of them begin as a pressure 
 gangrene of a small zone of the skin, the sub- 
 cutem and the underlying ligament. The mi- 
 crobian florae of these lesions are the usual horde 
 of stajDhylococci and bacilli that ordinarily hi- 
 fect woimds of horses. In one specimen taken 
 from our clinic, Prof. Herzog isolated the 
 Bacillus necrophorus in addition to tlie otliers, 
 The ligament once attacked is slowly invaded 
 farther and farther along its course and the 
 underlying spines become implicated. That is. 
 the disease once seated becomes progressive, 
 
PATHOGENESIS 53 
 
 because the cavity, pointing upward, does not 
 drain and the pus-soaked dead elements of the 
 hgament remaining stubbornly attached to the 
 living, favor the gradual onward march of the 
 process of destruction. Those originating pos- 
 teriorly travel forward into the ligamentum 
 nuch^ under the connective tissue of the mane 
 and thus seat themselves at just the same point 
 as the atypical form, the chief difference being 
 the amount of bone involvement, which in the 
 atypical form is always more pronounced than 
 in the other. Beginning at the highest point 
 of the withers from a serious pressure necrosis 
 from the harness, this form is more prone to 
 travel downward into the spines, ofttimes at- 
 tacking two or more of them with an acute 
 destructive osteitis that travels down toward 
 the bodies of the vertebrae casting off se- 
 questra and fusing them together with a mass 
 of connective tissue that is very slow to recon- 
 nect itself to the surrounding integuments, 
 even after the pathological process has other- 
 wise terminated. 
 
 Tlie disease is most common in horses whose 
 withers are thin of flesh from hard work and 
 privation. The vitality thus reduced is a dom- 
 inating etiological factor. The enfeebled tissue 
 becomes the prey of tlie virulent infection in- 
 troduced through and harbored by the harness 
 
54 FISTULA AND POLL-EVIL 
 
 sore. The local dry gangrene called sit fast at 
 the level of the collar seat is one of the com- 
 monest causes as well as the initial lesion of the 
 very gravest of fistulas of this kind. Here the 
 thick, folded, hair-clothed skin and also the 
 thick pad of connective tissue underlying the 
 mane first undergo gangrene from collar pres- 
 sure. Some of these sitfasts involve only the 
 skin (superficial sitfast), others invade into 
 the connective tissue and still others entirely 
 through it, exposing the ligamentum nuchse 
 beneath. From this exposure the process 
 marches on along the course of the ligament 
 and there sows the seed of a chronic state pre- 
 cisely the same as fistula from other causes, 
 and requiring the same remedial measures. In 
 fact, it is our experience that fistula of this 
 origin are the most stubborn of all. 
 
 Once seated in the ligament and bones, 
 atypical fistula is identical with the one having 
 its origin in a pre-existing cyst (typical fistula) 
 and will henceforth undergo the same course of 
 successive abscess and tract formation. Ab- 
 scesses form, burrow to the surface, discharge 
 for a time, heal up, gather again and burst at 
 another point, and this chain of events may re- 
 cur indefinitely. During the formation of a 
 new abscess there is local pain, distressed move- 
 ments, fever and a general indisposition just 
 
PATHOGENESIS 65 
 
 the same as during the abscess formation of the 
 typical form. There is, however, never as much 
 fibrous tissue formed as in the other variety. 
 Although the environs of the tracts and ab- 
 scess are surrounded by fibrous tissue it is 
 never so abundant. Voluminous fibrosis is an 
 attribute only of slowly forming typical fistula. 
 
 The secondary pus cavities of atypical fis- 
 tula are more superficial than those of the 
 typical kind, particularly during the early 
 stages. These are often subcutaneous, some- 
 times just under the superficial fascia and at 
 other times simply under the trapezius, but 
 later when the disease has become more deeply 
 seated and has traveled anteriorly along the 
 ligament, they may be found in the same deep 
 locations as in the typical forms. On the 
 other hand, it might be said here that these 
 superficial abscesses do not occur except in the 
 atypical ones, except when lancing or other 
 improperly directed treatment causes them. 
 
 The differences pathologically between these 
 two forms might be summarized as follows : 
 
 1. Typical fistulcC originate in sterile cysts 
 located on or adjacent to the second dorsal 
 spine. 
 
 2. The cause of typical fistula is unknown, 
 and the influence under which the cyst develops 
 
56 FISTULA AND POLL-EVIL 
 
 a well defined limiting wall is likewise not un- 
 derstood. It simulates tumor formation. 
 
 3. Typical fistulae develop deep secondary 
 abscess during the early phase of the phleg- 
 monous stage, while atypical ones develop these 
 only in the later stages. The early abscess 
 cavities of the latter are superficial. 
 
 4. Fibrosis, that is, the formation of fibrous 
 tissue is more pronounced in the typical form 
 and is never voluminous in the other. 
 
 5. Bone involvement is more certain and al- 
 ways more extensive in the atypical forms. 
 
 6. The toxemia is more pronounced in the 
 early stages of the typical form, but in later 
 stages both are alike in this connection. 
 
SYMPTOMS 
 
 The initial stage of typical fistula of the 
 withers develops unnoticed. As long as the 
 cyst located in its mesial position is not large 
 enough to hulge to the exterior of the body on 
 one side or the other and before it has become 
 infected with pyogenic microorganisms, there 
 are no symptoms that would attract attention 
 to the developing disorder of the region. 
 Everything is normal in appearance and the 
 patient suffers no apparent discomfort. Yet 
 there is this initial stage of fistula of the withers 
 to reckon with. How long the trouble is de- 
 veloping at the center before there is any 
 change in the profile of the region is not known. 
 The fact, however, that we find on post-mortem 
 examinations accumulations of a serous fluid 
 at the level of the second dorsal spine varying 
 from small sacs the size of an egg to that of a 
 base ball enclosed in a feebly developed sac, in 
 animals tliat were never suspected of having 
 any such a condition and wliicli died from other 
 causes, is ample evidence tliat tlie disease exists 
 a long time before the symptoms begin to ap- 
 pear. Finally, however, the region begins to 
 enlarge, first on one side and then on the other. 
 
58 FISTULA AND POLL-EVIL 
 
 In rare cases both sides bulge simultaneously. 
 The bulging may take the form of a circum- 
 scribed spherical protrusion or it may be dif- 
 fuse, extending evenly forward over the base of 
 the neck and backward over the withers with 
 its crest opposite the cephalic angle of the 
 scajiula or slightly forward from that point= 
 When both sides bulge from a diffuse enlarge- 
 ment, the withers may appear enormous in 
 width and elevation, sometimes to the extent 
 of making the patient seem top-heavy. If the 
 cavity is not artificially evacuated, nor other- 
 wise molested, the enlargement may remain un- 
 changed indefinitely. We have in mind cases 
 remaining in the saccular stage for more than 
 two years with no other changes pathologically 
 than that of becoming less fluctuant from the 
 development of its fibrous encapsulation, and 
 not infrequently we have seen them disappear 
 entirely. There is no way to predict accurately 
 when any given case will suppurate. 
 
 Finally, the great majority of cases pass into 
 the phlegmonous stage ; that is, they become in- 
 flamed from the invasion of microorganisms. 
 This event is announced by local pain, radiating 
 lines extending from the crest of the enlarge- 
 ment, indisposition to move, grunting, fever 
 and general depression. Cases that become in- 
 fected before the cyst is large enough to bulge 
 
SYMPTOMS 59 
 
 out the neck may prove puzzling in the absence 
 of any pathognomic symptom. 
 
 Then again we must differentiate (before 
 suppuration unmasks the character of the ail- 
 ment) fistula from other enlargements and 
 growths in the region. Sarcomata and melan- 
 osis may localize on the withers, and unless 
 taken into account there is some danger of 
 error in diagnosis. The former is, however, 
 rare and the latter is seen only in white horses. 
 A black work horse, submitted to the writer by 
 Dr. D. JNI. Campbell, exhibiting a voluminous 
 enlargement of the withers that had every re- 
 semblance of the fibrosis of fistula, w^as found 
 after an unsuccessful operation to be affected 
 with a very large, deeply rooted sarcoma ex- 
 tending downward into the thorax and affect- 
 ing nearly the whole of one lung in addition to 
 involving all of the structures about the 
 withers. And again, the author once submitted 
 a twelve-year-old horse, just turning white, to 
 an operation for fistula only to find that the 
 bulging was due to a melanotic tumor the size 
 of a cocoanut, located in the splenius. 
 
 It is also important to judge carefidly recent 
 swellings of the base of the neck and of the 
 withers, as these might be mistaken for fistula. 
 Horses frequently sustain severe contusions in 
 this region, exhibiting either fluctuant or firm 
 
60 FISTULA AND POLL-EVIL 
 
 swellings that are not easy to differentiate from 
 the saccular and phlegmonous conditions as- 
 sociated with the graver state preceding the 
 fistulous stage. Subcutaneous and subfascial 
 sanguinous sacs and hemotomata complicated 
 or uncomplicated with infection, are the mos^ 
 misleading of these lesions for which fistulas 
 might be mistaken. The differentiation can 
 never be made with certainty until the behavior 
 of the swelling is noted, both before and after 
 evacuating the contents. In fistula such swell- 
 ings accentuate; in the others they subside, 
 either with or without lancing. Besides they 
 are always diffuse whereas the fistulas presents 
 a spherical swelling in almost every instance. 
 
 Although acute diseases running short 
 courses, malignant edema and other erysip- 
 elatous inflammations when attacking the 
 withers may at first mislead the diagnostician, 
 these are recognized by their acuteness and 
 rapid advancement into adjacent regions and 
 the serious concomitant toxemia. 
 
 The early symptoms of the atypical form are 
 likewise very often misleading. That any given 
 harness sore will or will not end favorably is 
 not always easy to determine. Wliat might at 
 first seem like a simple enough harness sore 
 may finally prove to be the initial phase of a 
 bad fistula. On the other liand, a badly in- 
 
SYMPTOMS 61 
 
 flamed back may heal promptly. It is, there- 
 fore, advisable to withhold an opinion about 
 the seriousness of harness sores until the be- 
 havior of the swelling and of the discharge 
 can be noted. As a rule, however, a sore that 
 exposes the ligament, and especially if the 
 pain on palpation is excruciating and extends 
 along the back some distance from it, is one 
 to be viewed with suspicion. Painful subacute 
 diffuse swellings extending forward over the 
 summit of the withers are likewise incriminat- 
 ing. Both of these circumstances indicate an 
 extensive involvement of the ligament and un- 
 derlying bones right from the beginning that 
 is pretty sure to lead to a chronic inflammation 
 of these structures far beyond the original 
 focus — the harness sore. 
 
 Sitfast of the collar seat, on the contrary, 
 develops into fistula without these threatening 
 external manifestations, and even without any 
 perceptible pain. It causes fistula by rooting 
 through the connective tissue of the mane into 
 the ligament almost unnoticed. It is only when 
 sequestration begins or when extirpation is 
 attempted that the depth and the seriousness 
 are determined. 
 
 During this first stage of atypical fistula — 
 which in this case is the phlegmonous stage — 
 the patient is not stricken with illness as during 
 
62 FISTULA AND POLL-EVIL 
 
 the same stage of the typical form. The trouble 
 is thus far more like simple superficial abscess 
 and is not attended with any serious toxemia. 
 The toxins escape through the wound, whereas 
 in the typical form they are pent up and ab- 
 sorbed. It is only during the development of 
 secondary abscesses that any serious systemic 
 indisposition is ever observed. 
 
 The syviptoms of the fistulous stage. Fistula 
 once a reality and beyond the developmental 
 stage produces a clinical picture well known to 
 everyone having had any experience with 
 horses. Its exposition, if not also its descrip- 
 tion, might seem unnecessary for the average 
 reader, so well known are the manifestations 
 of this fell and loathsome disease. 
 
 It might be said for information of the 
 novice that any chronic discharge of pus from 
 or about the withers is fistula of the withers. 
 It may be from a single aperture and unas- 
 sociated with swelling or it may be from two 
 or more apertures with voluminous enlarge- 
 ment of the region on one or on both sides. 
 The apertures may be located posteriorh^ me- 
 sially or anteriorly, on or near the median line 
 or laterally at any point about the neck or 
 shoulders. The most anterior location at which 
 apertures are found is the middle cervical 
 region and the most posterior location is the 
 
SYMPTOMS 63 
 
 acnestis. These two extremes are, however, 
 rare ones. Most of the apertures are found on 
 or about the level of the withers and base of the 
 neck. Ventrally pus sometimes burrows sub- 
 cutaneously over the lateral face of the scapula 
 and points at the level of the shoulder joint 
 and more commonly a few inches above that 
 level. The amount of pus discharged varies 
 with the size of the cavity. After lancing, 
 after the first spontaneous bursting or after a 
 secondary abscess has been evacuated arti- 
 ficially or otherwise, the discharge is sometimes 
 very copious, overrunning the sides of the body 
 as far down as the foot and by dessicating en- 
 crusts itself thickly over the whole shoulder 
 region and forearm. The discharge finally 
 moderates and may even cease entirely pend- 
 ing the formation of a new abscess and new 
 aperture often on the opposite side or at some 
 remote location on the same side, causing the 
 same loathsome condition all over again. 
 
 In the meantime the patient loses flesh and 
 is unthrifty in general appearance. The coat 
 is dull and uncouth, the ribs and skeletal angles 
 become visible, and the reduced vitality be- 
 comes more apparent. It is only the patient 
 that is well groomed, well fed and well attended 
 as to its infirmity that remains in good con- 
 dition. The neglected subject sinks rapidly 
 
64 FISTULA AND PGLL-EVIL 
 
 into a still lower state of depression and may 
 even die from chronic septicema. Operated on 
 in this enfeebled state fatalities are of common 
 occurrence. 
 
 The profile of the withers during the course 
 of the fistulous stage varies in different cases. 
 Some are tumefied on one side, some on both, 
 usually from fibrosis but also from common in- 
 flammatory swellings which subside with each 
 pointing of the abscess. Each aperture leaves 
 a tell-tale scar and a denuded zone beneath 
 where the discharges have destroyed the hair 
 follicles. Where caustics, strong blisters or 
 strong chemical irrigations have been em- 
 ployed this marring is still more pronounced 
 (see Fig. 4). 
 
 Where the disease was left to run its own 
 course, or was treated by only palliative meas- 
 ures, the withers, neck and shoulders are left 
 riddled with these indelible blemishes, and 
 often through extensive sloughing of the liga- 
 mentum nuchge the neck drops down in front 
 of the withers into a permanent deformity 
 (ewe -neck). 
 
 In other cases the spines at the summit of the 
 withers having lost their ligamentous covering 
 protrude beneath the imperfectly regenerated 
 integument and thereafter become the seat of 
 sores from the harness and saddle that are diffi- 
 
SYMPTOMS 65 
 
 cult to heal. At the sides of the neck just in 
 front of the cephalic angle of the scapula the 
 permanently enlarged musculature covered 
 with denuded skin likewise chafes from the 
 collar and thus proves a constant annoyance. 
 JNIarred and sore-ridden, the subject is un- 
 salable and ofttimes almost useless. 
 
TREATMENT 
 
 The assertion that all fistulas of the withers 
 might, to the best advantage, be submitted to 
 a uniform (standard) method of treatment is 
 a paradox. It is a paradox because such a 
 statement at first thought apparently false is 
 after all entirely true, as the treatment needs 
 to vary only in regard to its details. The same 
 general principles of management and treat- 
 ment may be laid down for all of them, no 
 matter from what source they originate, the 
 course they may have taken, or the stage in 
 which they are found when submitted for the 
 surgeon's deliberation. 
 
 That certain fistulge of the withers do some- 
 times yield to lateral lancings and irrigations 
 is not denied, but that the great majority surely 
 but slowly develop into grave, enfeebling, in- 
 curable and often fatal afflictions in spite of 
 such treatment is equally true. 
 
 It is, therefore, evident that prompt treat- 
 ment of the radical sort is indicated at an early 
 stage and before the infections of extraneous 
 origin have done a widespread damage to the 
 ligaments, bones and muscles, and before pus 
 has burrowed into the inaccessible recesses of 
 this complex region. 
 
68 FISTULA AND POLL-EVIL 
 
 It does not matter whether the condition has 
 been caused by an abrasion or has originated in 
 li cyst of the dorsal bursa, procrastination is 
 inadvisable. 
 
 We have found, however, in the cases of typi- 
 cal fistulse that the evacuation of the contents 
 of the sac one week before the radical operation 
 is performed, is good practice, because it forti- 
 fies the tissues against post-operative infections 
 of a grave character. Where strict aseptic con- 
 ditions are maintained in the operation and 
 the patient has skillful after-care, this precau- 
 tion is not as essential as when careless methods 
 prevail or when the after-care must be con- 
 signed to untrained hands. 
 
 It is, therefore, recommended, as a routine 
 measure in field practice, to lance the cyst, 
 evacuate the liquid and flocculent contents and 
 then submit the sac to casual irrigations one 
 week to ten days before operating. 
 
 In the case of old fistulee originating as 
 cysts and which have become infected from 
 any source or in the traumatic variety having 
 either superficial or deep pus accumulations, 
 lancing one week before operating is likewise 
 helpful in that surgical shock is modified and 
 there is less soiling of the surgical wound with 
 pus during the operation. 
 
 These suggestions need not be laid down as 
 
TREATMENT 69 
 
 absolute laws, but it is advisable to follow them 
 where it is desired to take advantage of every 
 helpful influence. They are most important 
 in subjects enfeebled from hard work or x)ri- 
 vation and when from any cause a clean opera- 
 tion and good after-care cannot be carried out. 
 
 External applications such as liniments and 
 blisters we do not recommend. They only 
 complicate matters by irritating the skin and 
 encrusting it with dried excretions difficult to 
 remove in preparing the field for operation 
 later, and so far as we have been able to de- 
 termine they do not in any way influence the 
 course of the disease within. Occasional cases 
 abort in the cystic stage but this trend is spon- 
 taneous and is not hastened by local applica- 
 tions, and it is by no means certain that the 
 decrease in the size of the enlargement is per- 
 manent. Our observations indicate that at 
 least some of these rare cases recur and finally 
 burst to the surface. 
 
 As regards the application of caustic chemi- 
 cal substances into the tracts we doubt if there 
 is any charlatanry, ancient, medieval or mod- 
 ern, that savors more of cruelty and malprac- 
 tice. The caustics — arsenic, copper sulphate, 
 lye, corrosive sublimate, caustic lime, zinc 
 clilorid, etc., after dissolving in the albuminous 
 secretions overflow the surface of the bodv. 
 
70 FISTULA AND POLL-EVIL 
 
 cause severe pain, prolonged discomfort and 
 permanent blemish. Often large patches of 
 integument slough away ( Fig. 4 ) . 
 
 The only beneficial effect of caustics is the 
 widening of the aperture and tract for drain- 
 age and since this can be accomplished better 
 and without discomfort by other means the one 
 argument in their favor loses force. 
 
 The treatment of fistula of the withers which 
 in our hands has given the best results is 
 prompt, thorough, surgical intervention. Our 
 operation of choice and which is hereinafter de- 
 scribed consists of a median line incision ex- 
 tending from the crest of the withers forwards 
 six to twelve inches and downward through the 
 skin, the pad of the mane and then between the 
 two halves of the ligamentum nuchas into the 
 space beneath lying over the summits of the 
 second and third thoracic vertebrse. This is 
 followed by a resection of such parts of the 
 ligamentum nuchge as are thought to be harm- 
 ful and then by making lateral drainage 
 apertures from the bottom of the cavity to the 
 surface of the cervical region into which a 
 perforated drainage tube is inserted. 
 
 Radical Operation for Fistula of the Withers 
 
 Prepai^ation. — As the procedure is one of 
 some magnitude, attended with all of the dan- 
 
Fig. 4. — Effects of the Use of Caustics. 
 This mule was treated for a typica;! fistula of the withers 
 by the injection of concentrated lye. Discharge from the 
 wound occasioned sloughing of the skin over large areas. 
 
72 FISTULA AND POLL-EVIL 
 
 gers of major operations, it is essential to in- 
 vestigate carefully into the patient's physical 
 condition. Weak, emaciated, enfeebled sub- 
 jects should be given a preparatory treatment 
 that will tend to build them up in strength and 
 vigor. This may consist in evacuating and 
 irrigating large abscesses, cleaning them up 
 over the soiled shoulders, grooming the body, 
 good feeding and any general good care that 
 will improve the health» The week or two re- 
 quired for such preparatory treatment is not 
 lost, since the improved health before the op- 
 eration will shorten the duration of the period 
 of post-operative convalescence, and will re- 
 duce the rate of mortality which in enfeebled 
 subjects is bound to be high on account of 
 shock and the magnitude of the invading 
 wound. Large wounds cannot be made in the 
 bodies of an animal with impunity; in en- 
 feebled subjects they are positively disastrous. 
 Infections run riot in them and without ef- 
 fectual resistance toxemias are fatal. We, 
 therefore, advise against the operation in sub- 
 jects not physically fit to stand the ordeal. 
 
 Dieting is also essential as a preparatory 
 step, as no animal may be safely cast and sub- 
 mitted to a severe surgical operation with its 
 alimentary canal filled with ingesta. This is 
 especially the case with subjects to be anesthe- 
 
TREATMENT 73 
 
 tized, with chloroform or narcotized with 
 chloral. 
 
 Preparation of the Field. — Scraping off the 
 dried pus encrusted over the shoulders, wash- 
 ing the skin with soap and hot water must pre- 
 cede the attention to the field itself, as other- 
 wise no effectual cleansing of the withers for 
 surgical work would be effectual. Preferably 
 this should be done on the day preceding the 
 oj^eration, and to prevent further soiling the 
 shoulders might be annointed with vaseline. 
 
 The hair over the withers and on each side, 
 down no less than ten inches, is clipped and if 
 possible shaved. The mane is clipped off well 
 forward over the seat of the collar and the re- 
 maining mane is braided to prevent its tufts 
 from dangling into the wound as well as to 
 keep it free from pus during the after-treat- 
 ment. 
 
 A good ablution with brisk friction of mer- 
 curic chlorid in the dilution of not less than one 
 part to fi\e himdred is much the best prepara- 
 tory disinfection of the skin along the line of 
 incision. The field might in addition be 
 painted with tinctin*e of iodin. Shaving the 
 mane hairs especially on the neck where the 
 skin is folded transversely is difficult and very 
 tedious as the folds are closed while the liead is 
 erect and as a painstaking shaving process pro- 
 
74 FISTULA AND POLL-EVIL 
 
 longs the duration of decumbency we have in 
 our recent operations been satisfied with chp- 
 ping. By using the curved scissors these 
 coarse hairs, even those between the folds can 
 be trimmed away. In order to conserve the sub- 
 ject's strength by shortening the duration of 
 the operation proper it is, however, preferable 
 that all of this cleaning up process and disin- 
 fection be done in the standing position. By 
 standing upon an elevation in a place where the 
 patient's movements can be controlled and by 
 twitching the nose, a more thorough cleaning 
 can be given in the standing position than after 
 the animal has been cast. When the body lies 
 flat on the mat, ground or even the operating 
 table, the sides of the withers are less accessible 
 for clipping and washing, and besides when 
 this is postponed until the subject is down, the 
 ground under and about the withers becomes a 
 disagreeable place to occupy while operating. 
 
 Anesthesia. — Chloroform anesthesia is much 
 the best, although narcosis with chloral hydrate 
 administered no less than one hour before 
 casting will answer when the retinue lacks a 
 satisfactory anesthetist. 
 
 For this purpose we administer per os, pref- 
 erably as a drench twelve drams of chloral 
 dissolved in one quart of warm water. Cannabis 
 indica intravenously, chloral in the peritoneal 
 
TREATMENT 75 
 
 cavity or morphin hypodermically may be 
 substituted, but in our hands these agents have 
 been greater disappointments as surgical nar- 
 cotics than chloral hydrate, which, given as 
 above described on an empty stomach, always 
 produces some measure of blunted sensibility 
 that facilitates the control of the patient if it 
 does nothing more. 
 
 When chloroform anesthesia is used, every- 
 thing is made ready before it is administered in 
 order to shorten the duration of unconscious- 
 ness to the minimum. 
 
 Restraint. — The standing position even with 
 the best stocks is by no means an adequate 
 restraint for effectual work. The lunging sub- 
 ject is in danger of injury and the movements 
 of the neck prevent accuracy of technic. The 
 standing position answers well enough for lat- 
 eral incisions, such as may be required to evac- 
 uate abscesses preparatory to the operation, 
 but when the center of the withers must be in- 
 vaded for the purpose of resecting a necrotic 
 ligament or of perforating the cervical muscles 
 for drainage, the control must be complete — 
 perfect. 
 
 The preferable method is rope restraint, with 
 all fours folded securely under the body. The 
 collar part of the rope must pass from breast 
 
76 FISTULA AND POLL-EVIL 
 
 to back instead of encircling the neck. The 
 collar seat must be free from obstacles because 
 the incision crosses it and besides a rope en- 
 circling the base of the neck would interfere 
 with making the lateral apertures for drainage. 
 A rope whose collar is large enough to drop 
 under the sternum while its backward part will 
 rest in the middle of the back is best adapted 
 for the purj)ose, as it leaves the withers unob- 
 structed. The two free ends of the rope en- 
 circle the pasterns of the hind legs and then 
 pass forward into the collar. When the horse is 
 down the hind legs are drawn into a securely 
 flexed position. The fore legs are tied securely, 
 flexed with straps or preferably with cords. 
 Thus secured the body of the anesthetized or 
 narcotized subject can be rolled into the ventral 
 position where it can be blocked with sacks or 
 held by several assistants. The operator stand- 
 ing on the right side is now in a splendid posi- 
 tion to proceed. 
 
 On the operating table which brings the body 
 up to a position comfortable enough to invade 
 the withers mesially there is the objection that 
 the under side is not very accessible for making 
 the lateral apertures. Although this objection 
 can be overcome by rolling the liead and neck 
 downward and backward there is by no means 
 the same opportunity to perforate the cervical 
 
Fig. 5. — Tumor forceps of a serviceable pattern for fistula 
 operation. The style of the jaws in tumor forceps is a mat- 
 ter that should be carefully noted in purchasing such an in- 
 strument. For instance, some vulsellum forceps are so de- 
 signed that the incomplete curve of the jaws together with 
 their slender and weak construction makes them too delicate 
 for much veterinary surgical work. The instrument illus- 
 trated above is designed so that with them a firm grasp of 
 tissues is possible and a secure hold is insured. 
 
 Fig. 6. — Drainage Tube and Inserter. 
 By means of the drainage tube inserter it is possible to in- 
 troduce a rubber drainage tube with a minimum of invasion 
 of sound tissue. This, in many cases, is an important fac- 
 tor, as it prevents needless contamination of uninvaded parts, 
 limits the area of infected tissue and possible resultant com- 
 plications and greatly facilitates the execution of this part of 
 the technic. Hemorrhage is reduced to a minimum, opera- 
 tions are completed with dispatch and, therefore, with less 
 danger of surgical shock when these appliances are employed. 
 
78 FISTULA AND POLL-EVIL 
 
 muscles as when the subject is tied in ropes and 
 rolled into the ventral position. 
 
 histruments Required. — A good strong and 
 well sharpened scalpel; a probe pointed 
 bistoury, two large tumor forceps, an assort- 
 ment of hemostats, a drainage tube inserter, 
 a perforated rubber drainage hose, a large 
 needle threaded with strong material. There 
 will be needed in addition to the usual basins 
 for antiseptics, a separate basin containing an 
 abundance of oakum, which is to be used for 
 packing the cavity immediately after the op- 
 eration has been completed. We use clean 
 oakum soaked in a strong solution of mercuric 
 chlorid for this purpose and with this we place 
 the threaded needle to prevent its thread from 
 becoming entangled among the instruments 
 while operating. 
 
 A yard of muslin or burlap will also be 
 needed to cover the withers as a protection 
 against soiling after the patient is returned to 
 the stable. 
 
 Tech7iic. — Standing on the side of the 
 patient now rolled in the ventral position, 
 facing toward its head, the operator plunges 
 the scalpel deeply into the middle of the neck 
 at a point varying from six inches to twelve 
 inches in front of the crest of the withers, and 
 then draws it backward as far as the crest — the 
 
TREATMENT 79 
 
 full depth of the blade. The variation in length 
 of the incision is necessitated by the difference 
 in the size of the patient, in the thickness of 
 the skin and underlying pad, and also by the 
 size of the tumefaction. In a small horse, for 
 example, having only a small rounded sac 
 bulging at one side, an incision six inches long 
 will be found ample, while in a large "meaty- 
 necked" draft horse having an enormous swell- 
 ing it must be at least twelve inches long. 
 Otherwise the walls of the wound cannot be 
 parted enough to give a good access to the bot- 
 tom of the cavity for inspection and for resec- 
 tion of diseased parts of the ligament. We 
 aim in the first stroke of the knife to incise 
 the skin and underlying pad from end to end, 
 that is, from the point decided upon anteriorly 
 to the crest of the withers. For descriptive 
 purposes this may be designated the first step 
 of the operation. 
 
 In the second step each of the edges of this 
 large wound is grasped deeply with the tumor 
 forceps. An assistant should hold one of the 
 forceps and the operator the other By draw- 
 ing the wound apart with some force the bleed- 
 ing now spurting from many small vessels is 
 immediately controlled and after Avidening it 
 out, a good view^ of the bottom is obtained for 
 the next incision. The scalpel is now plunged 
 
80 FISTULA AND POLL-EVIL 
 
 between the two halves of the funniciilar por- 
 tion of the hgamentum nuchge into the loose 
 tissue beneath and drawn backward again the 
 full length of the wound. This opens the cen- 
 tral cavity which in typical fixtula^ is uni- 
 formly located at the level of the second tho- 
 racic spine. 
 
 The third step. Blood is now hurriedly wiped 
 out, the forceps are drawn upon with force to 
 reduce the flow and the large spurters are 
 snapped up in hemostats. It is not, however, 
 advisable to devote much time to this hemo- 
 stasia unless efforts at its control promise to be 
 promptly effectual, since futile attemj)ts de- 
 lay the work and add to the blood loss. If the 
 operation antedates the formation of pus, that 
 is, if the contents are still sero-fibrinous, there 
 is no occasion for doing anything else than that 
 of now inserting the drainage tube, while on 
 the other hand, if there is pus and the ligament 
 is found more or less riddled with disease, re- 
 section of the diseased parts is now under- 
 taken. In very old cases it is entirely removed, 
 in more recent cases its mesial parts are sliced 
 off. In this step we also in many cases en- 
 deavor to resect the wall of the sac, or as mucli 
 of it as is accessible for hurried removal, leav- 
 ing the ligament imtouched. This, of course, 
 is possible only where the sac is small and on 
 
TREATMENT 81 
 
 account of age has a well defined limiting wall. 
 It is often possible in many cases to resect the 
 sac and then heal up the wound under aseptic 
 conditions without drainage. More often, 
 however, the region is invaded with infection 
 of long duration and exhibits necrotic areas 
 which must be removed. For example, if the 
 ligament is found carpeted with undulated 
 granulations and is seen to exhibit necrotic 
 spots or is riddled with pus tracts, it should be 
 entirely removed The resection is effected by 
 cutting it off anteriorly, grasping the end with 
 a tumor forceps and then dissecting it in the 
 backward direction to the posterior commis- 
 sure of the wound. This is done on both sides 
 or only on one side according to the condition 
 in which the ligament is found. When not too 
 firmly fixed into the adjacent connecting tis- 
 sue it can often be torn out with the tumor 
 forceps. 
 
 The bones beneath are left severely alone. 
 Trimming with bone forceps or curette is not 
 recommended. Spontaneous exfoliation is de- 
 pended upon exclusively. We have found that 
 meddling with the spinous processes is a harm- 
 ful practice. The exposed curetted ends be- 
 come open channels for the descent of new and 
 deeper inflammatory processes, when later dur- 
 ing the healing they are constantly soaked in 
 
82 FISTULA AND POLL-EVIL 
 
 pus. Necrotic ends sooner or later, without in- 
 terference, separate from the viable bone, and 
 then leave it carpeted with granulations which 
 now cicatrize with the rest of the wound. We 
 are, therefore, unequivocally opposed to the 
 removal of bone tissue other than the already 
 welMoosened sequestra, which are sometimes 
 Found floating in the cavity or feebly attached 
 in situ. 
 
 The fourth step is the insertion of the drain- 
 age tube. This is done with the drainage tube 
 inserter. (Fig. 3.) 
 
 Armed with the tube the point of the inserter 
 is placed at the bottom of the cavity and then 
 pushed out laterally in the downward direction 
 through the splenius and serratus cervicis mus- 
 cles to the surface. The skin must be incised 
 as the j)oint of the inserter bulges it out as its 
 point is not sharp enough to penetrate it un- 
 assisted by an incision. When inserted on the 
 one side the inserter is passed into the other 
 end of the tube and pushed through the same 
 place on the opposite side. This places the 
 tube across the bottom of the cavity and out to 
 each side of the neck. (Fig. 4.) 
 
 When the operation is prolonged for any 
 cause and the blood loss has been great, we 
 postpone the insertion of the tube until the 
 
TREATMENT 
 
 second day, at which time it is inserted in the 
 standing position. 
 
 It is advisable in passing tubes through this 
 thick musculature to keep the neck in a nor- 
 
 Inserting the Drainage Tube. 
 
 mal position. Otherwise the tube will be in a 
 strained position. 
 
 The fifth step is that of packing and sutur- 
 ing the cavity. For this we use sterilized anti- 
 septic oakum. We prepare the oakum already 
 
84 FISTULA AND POLL-EVIL 
 
 arranged in wads of different sizes so that it 
 can be packed into the recesses piece by piece 
 where it will press directly upon the bleeding 
 vessels and thus arrest the hemorrhage at once. 
 If indifference is displayed in this connection, 
 the bleeding may force its way between the 
 
 Fig. 8. — The Drainage Tube Inserted. 
 This shows the position of the drainage tube in an atypical 
 case of fistula before the would is sutured. In typical fistula 
 the tube would be inserted more anterior, making its exit at 
 the point marked X. 
 
 layers of the surrounding tissues. Once well 
 packed the wound is closed with sutures deeply 
 inserted into each lip. The wound must be 
 closed tight to prevent any further blood loss. 
 Dressmg. When the patient rises to its feet, 
 its body is washed free of all blood accumula- 
 
TREATMENT 85 
 
 tions, and rubbed as dry as possible. We then 
 cover the withers with a layer of cotton or 
 gauze and hold it in place with a muslin or bur- 
 lajD sheet tied down with cords encircling the 
 breast and the girth. Tlie patient is now ready 
 for the stall. 
 
 After-care. At the end of twenty- four hours 
 
 Fig. 9. — The Drainage Tube After the Wound Has Been 
 Sutured, Typical Fistula. 
 
 the sutures are removed and the packing lifted 
 out carefully. There is at this time still some, 
 danger of bleeding if the interior of the cavity 
 is harshly handled. We, therefore, advise that 
 no attempt be made to clean out the blood clots 
 attached here and there about the cavity until 
 the end of forty-eight hours, but that we con- 
 tent ourselves with a second packing of oakum 
 
S6 FISTULA AND POLL-EVIL 
 
 or gauze soaked in mercuric chlorid solution 
 and bound down with the withers bandage. At 
 the end of forty-eight hours we give the whole 
 cavity a good cleaning under strict aseptic pre- 
 cautions, removing the blood clots attached to 
 the tissue completely. The cavity is now 
 sprinkled with iodoform and then filled up with 
 
 Fig. 10. — The Drainage Tube After the Wound Has Been 
 Sutured, Atypical Fistula. 
 
 a mixture consisting of iodoform five per cent 
 and boric acid ninety-five per cent and the 
 withers protected again with clean cotton and 
 the bandage. 
 
 In cases where the wound has not been soiled 
 during the operation a daily renewal of the 
 antiseptic powder after wiping out the old will 
 
TREATMENT 87 
 
 answer for the after-care, but where the cavity 
 was found badly infected or in instances where 
 the operation was not a perfectly clean one, it 
 is essential that the powder be renewed no less 
 frequently than three times a day for the first 
 four days. By attending with great care to 
 this large wound, the discharges will not be 
 abundant, but when the whole area of exposed 
 flesh is allowed to become contaminated the is- 
 sue is copious. It is, therefore, important to 
 pay strict attention to the wound, treating it 
 skillfully during the first four days. After 
 four days there is less danger of grave infec- 
 tions gaining any headway in the wound as 
 the tissues are then better protected against 
 microbian invasion. 
 
 The drainage tube is managed much like a 
 seton. We fasten a spike across one end and 
 then pull it through from the other end and 
 give the holes and lumen a good cleaning. A 
 stylet is needed to dislodge the dried pus that 
 chokes it. By bending it about, cleaning its 
 holes and ramming a stylet through its lumen 
 and then rinsing it well with a strong antisep- 
 tic solution, it can be kept perfectly clean and 
 open. The next day the same manner of hand- 
 ling is repeated except that it is draw^n to the 
 opposite side. 
 
 Cases having an osseous comjilication should 
 
88 FISTULA AND POLL-EVIL 
 
 be watched more carefully. They must not be 
 allowed to close above before sequestration is 
 complete and the bone is in condition to cica- 
 trize with the rest of the wound. It is here 
 that recurrences occur. Stumps of bare verte- 
 brjE are covered by scar tissvie and cause a re- 
 accumulation of pus which will require subse- 
 quent attention if not a second operation of 
 equal magnitude. 
 
 During the healing of the wound its walls 
 are scrutinized daily for shreds of ligament 
 that are becoming surrounded with granula- 
 tions before detaching from their viable con- 
 tinuation. It often happens that large sloughs 
 of ligamentous or new-formed fibrous tissue 
 appear here and there about the cavity as cica- 
 trization proceeds. These delay healing and 
 should be removed as soon as possible. 
 
 At the end of five weeks we usually dispense 
 with the tube and apply such simple astring- 
 ents as a two per cent solution of zinc sul- 
 phate or common white lotion. At this time 
 horses may be worked with breast harness 
 but collar pressure directly upon the region is 
 not admissible until after three months have 
 elapsed. 
 
 Modifications 
 
 Large subcutaneous or subfascial abscesses 
 are evacuated at dependent points and drain- 
 
TREATMENT 89 
 
 age apertures maintained as long as there is 
 any issue from them. When the discharge 
 continues to be profuse, attempt should be 
 made to locate the cause. The main cavity has 
 not been drained. If located in an inaccessible 
 place, as for example upon the cervical verte- 
 brae (cervical fistula) or along the thoracic 
 vertebra under the longissimus dorsi, spinalis 
 or complexus, it may not be possible to give 
 helpful assistance. These secondary abscesses 
 are the result of improper treatment or neglect. 
 They seldom if ever complicate a well directed 
 operation followed by faithful after-care. 
 
 In the case of atypical fistula arising from 
 wounds of the back or crest, the operation is 
 much the same except that the incision is made 
 more posteriorly (Fig. 10). 
 
 It is, however, never advisable to make such 
 a median line incision on a thin horse having a 
 prominent, sharp withers, as the w^ound lips 
 will sag down below the level of the vertebra? 
 and produce a condition that will heal very 
 slowly and imperfectly. In draft horses with 
 thick, low withers there is less danger from this 
 standpoint. The fleshy surrounding affords 
 ample protection against protrusion of the 
 crest above the level of the wound edges. 
 
90 FISTULA AND POLL-EVIL 
 
 Special Remarks 
 
 Objections have been raised against the use 
 of drainage tubes in the treatment of fistula 
 on the grounds that they are difficult to keep 
 open. This objection we are sure comes from 
 those who have not persevered in their use. A 
 tube long enough to cross the neck and pro- 
 trude no less than eight inches on each side is 
 very easily cleaned without removing it en- 
 tirely, as described above, and after it has es- 
 tablished a good tract for itself it can be taken 
 out entirely for cleaning and can be easily rein- 
 serted. It is essential that a tube be composed 
 of strong material, strong enough to resist the 
 pressure upon it. It must not collapse. A 
 soft tube is worthless. When the strong mus- 
 cles through which it passes press upon it, its 
 usefulness for drainage is destroyed. We, 
 therefore, recommend a stong reinforced rub- 
 ber hose which we perforate with a harness 
 punch (Fig. 6.) 
 
 To prevent drainage tubes from coming out 
 we arm each end with a common twenty penny 
 nail passed across at right angles. A meat 
 skewer or common round stick will also answer 
 the same purpose. 
 
 It seems important to emphasize here the 
 worthlessness of mere incisions through thick 
 muscles as drainage apertures. A collaj)sed 
 
TREATMENT 91 
 
 aperture through muscle tissue does not drain 
 in the surgical sense. Such an aperture leaks 
 pus but does not drain the cavity dry enougli 
 to serve the purpose for which drainage is 
 needed. It does not matter how many drain- 
 age incisions are made through muscle tissue, 
 the cavitv would still overflow unless the aper- 
 tures are held wide open with a tube. The 
 same may be said of setons. While pus is ab- 
 sorbed by them (in very limited quantities) 
 they do not empty the cavity and are, there- 
 fore, worthless. To heal a wound as large as 
 the one required to expose the diseased part of 
 a fistula of the w^ithers, it is essential that it be 
 kept free from accumulations of its secretions. 
 
 Accidents and Sequelae 
 
 Septicemia is the commonest sequel of the 
 operation. It is predisposed by enfeebled 
 states of the patients but can often be traced 
 to badly directed surgical work. Failure to 
 obey the common laws of modern surgery as 
 regards asepsis is always disastrous in opera- 
 tions of this magnitude, and since this one is 
 performed often in a pus ridden region, dirty 
 internally and externally, and must often be 
 done where conditions are none too favorable, 
 the operation exacts its full toll of fatality 
 
92 FISTULA AND POLL-EVIL 
 
 from septicemia, even in the most vigorous sub- 
 jects. 
 
 The prevention hes in making the best of 
 the situation by using sterihzed instruments, 
 cleaning the hands well, packing the wound 
 with a safe wadding and then protecting it 
 thereafter until the danger of a grave infection 
 has passed. It is also very essential to remove 
 the packing material at the end of twenty- four 
 hours so that the blood supply of the tissues 
 pressed upon by the tight packing will be re- 
 stored to the walls of the wound. A packing 
 of doubtful purity wadded tightly into a 
 wound as large as this one is indeed a hazard. 
 It weakens the tissues and besides impregnates 
 them with infections. 
 
 Malignant Edema 
 
 We have had cases of malignant edema fol- 
 low operations where the directions given about 
 the removal of the packing were not carried 
 out. To let a packing sojourn forty-eight 
 hours in a large wound always invites anaer- 
 obic infections of this character. In fistula of 
 the withers it is positively disastrous. There 
 is danger from this disease even after appar- 
 ently clean operations because the condition 
 created is so favorable. The prompt removal 
 of the packing at the end of twenty- four hours 
 
TREATMENT 93 
 
 and the re-application of a well soaked anti- 
 septic pack is universally preventive. 
 
 Hemorrhage 
 
 The hlood loss, always considerable, often 
 reaches the danger point when large radicals 
 of the nutrient arteries are divided and the clos- 
 ing up of the wound is in some way delayed. 
 We depend more upon hasty work and prompt 
 closure of the cavity to limit the blood loss 
 than upon ligation or forcep hemostasia. Often 
 when blood is gushing from some part of the 
 wound in a threatening manner and a forcep 
 cannot be snapped upon it promptly we pack 
 the bleeding place with a hard wad of oakum 
 and let an assistant hold it down tight with a 
 long blunt instrument while the work proceeds 
 without further hindrance. While cognizant 
 of the fact that this is not a display of the best 
 surgery, it has always seemed impossible for 
 us to make any headway in the direction of sys- 
 tematic hemostasia in these operations and we 
 have come to the conclusion that less blood is 
 lost by hurrying through the work and then 
 depending upon the packing to prevent any 
 further loss. 
 
 In exceptionally large withers, infiltrated 
 with an abundance of newly formed fibrous tis- 
 sue, the woimd is of such magnitude that in 
 
94 FISTULA AND POLL-EVIL 
 
 spite of care the loss of blood assumes danger- 
 ous proportions. And while fatahties from 
 this cause are not usual, the weakened state 
 produced by excessive bleeding operates with 
 other influences against the general welfare of 
 the patient during the first few days of con- 
 valescence. 
 
 Recurrence 
 
 When the withers tumefy again after the 
 wound has been healed for some time or when 
 it does not heal in the usual time, it is evident 
 that some necrotic ligament or bone still re- 
 mains. These may have been overlooked in the 
 operation or else the disease may have ad- 
 vanced into adjacent places. We have found 
 that most of oiu* recurrences are due to healing 
 of the wound before the spines have cast off the 
 sequestra. A second operation of lesser mag- 
 nitude often reveals a loosened segment which 
 on removal is followed by j^rompt cicatrization. 
 When this is not found to be the cause a new 
 operation tlie same as the first may be required. 
 
 Complications 
 
 The complications arising from fistula of the 
 withers independent of those caused entirely 
 by operations and other remedial measured 
 M'hicli will be considered under the head of "se- 
 
TREATMENT 95 
 
 quels and accident" are: Acute septicemia, 
 chronic septicemia, pneumonia, pleurisy and 
 paralysis. 
 
 1. Septicemia. As already mentioned under 
 the chapter on pathogenesis, there is a toxemia 
 associated with every case of fistula. The only 
 exception is during the saccular stage of the 
 typical form. After infection has entered, the 
 situation is only a question of how badly the 
 patient is affected by this complication. Some 
 patients resist this systemic complication bet- 
 ter than others, but after a fistula has become 
 chronic and has drained the patient's vitality 
 by copious discharges of pus for a long while, 
 impregation of the organism with toxic prod- 
 ucts and bacteria occurs to a greater or less 
 extent in every case. Death from acute sep- 
 ticemia, except after operations, is rare, but 
 clinical chronic septicemia is a very common 
 occurrence. It is this complication that most 
 undermines the health of all cases and which 
 causes the emaciation and general enfeeble- 
 ment already referred to. And while the com- 
 plication is an insidious one, deaths occur 
 therefrom quite often. We have found sec- 
 ondary abscess of the lungs and of tlie spleen 
 in animals that have died from fistula. As a 
 source of focal infection fistulse of the with- 
 
96 
 
 FISTULA AND POLL-EVIL 
 
 ers is by far the best example we have in 
 domestic animal pathology. Its symptoms are 
 seen in the unthrifty and enfeebled state of 
 the patient and in its susceptibility to other 
 diseases, particularly to new infections after 
 
 
 Fig. 11. — A Complicated Case of Fistula and Poll-Evil. 
 
 operations, and to pneumonia — the common 
 form of dissolution of so many diseases. 
 
 Pneumonia 
 
 The pneumonia arising as a complication of 
 fistula of the withers occurs chiefly in old debil- 
 itated subjects or in younger animals reduced 
 to a state of general enf eeblement from neglect 
 and exposure. It is sometimes also metastatic- 
 abscess of the lungs — the infection is carried 
 ^from the purulent hot bed to the pulmonary 
 
TREATMENT 97 
 
 capillaries where the lung tissue falls an easy 
 prey to the subsequent pyogenesis. We have 
 found the lungs riddled with abscesses in af- 
 fected horses that have died from fistula. 
 
 Pleurisy 
 
 The pleura is occasionally attacked with an 
 inflammatory process arising from its conti- 
 nuity with the affected musculature sin-round- 
 ing it. The deep secondary abscesses which 
 burrow down to the bodies of the vertebra^ and 
 then descend over the costal surface are the in- 
 fluential factors in this connection. At first cir- 
 cumscribed, the inflammation soon extends over 
 a wider surface until the subject is affected with 
 a diffuse fatal sero-fibrinous pleuritis. Figure 
 11 illustrates a case affected both with poll-evil 
 and fistulee of the withers. The subject was 
 seven years and a fair type of delivery wagon 
 horse weighing eleven hundred and fifty 
 pounds. It was first attacked with poll-evil, 
 but before this was submitted for treatment 
 the withers were already tumefied with a 
 phlegmonous enlargement. The poll-evil was 
 submitted to the radical operation and 
 promptly cured after thirty days. During this 
 period of convalescence from the poll-evil oper- 
 ation, the withers pointed and discliarged a 
 copious quantity of pus on the right side ad- 
 
98 FISTULA AND POLL-EVIL 
 
 jacent to the cervical angle of the scapula. The 
 patient was not relieved from this evacuation 
 but on the contrary remained indisposed, re- 
 fusing to move about except when urged, and 
 at each movement grunted with agony. The 
 respirations at first only slightly accelerated 
 became gradually faster during the succeeding 
 three weeks, at which time several gallons of 
 exudate were aspirated from the right side of 
 the thorax. The patient's condition became 
 gradually worse and at six weeks following the 
 evacuation of the withers it died from a re- 
 filling of the pleural sacs. The post mortem 
 examination of the carcass showed clearly a 
 case of pleurisy beginning along the dorsal re- 
 gion extending with a gradual lessening in- 
 tensity in the downward direction over the 
 thoracic parietes, beginning at the intercostal 
 lymph nodes, which were found enlarged. 
 
 Paralysis 
 
 Nervous involvement is less likely to com- 
 plicate fistula of the withers than poll-evil, be- 
 cause the spinal cord of the dorsal region is 
 better protected against encroachment from 
 extending pyogenic processes. We have never- 
 theless observed cases in which death due to 
 spiTvitis arising from extension of the 
 disease into the neural canal. The patients al- 
 
TREATMENT 
 
 99 
 
 ready weakened from the disease and also from 
 general neglect weakened in the hind quarters 
 and after exhibiting a progressive paralytic 
 state, were finally found unable to rise, dying 
 in delirium after some days of decumbency. 
 
 Fig. 12. — Cold Abscess of the Prescapular Lymph Nodes. 
 Following Fistula of the Withers. 
 
 Cold Abscess of the Prescapular Lymph Nodes 
 
 The adjacent lymph nodes may suppurate 
 during or following fistula of the withers as 
 shown in case of a draft horse (Fig. 14) . After 
 recovering from an operation for a fistula of 
 the withers and before having been put to 
 work a pronounced enlargement developed at 
 
100 FISTULA AND POLL-EVIL 
 
 the shoulder. This proved to be a typical cold 
 abscess involving these lymph nodes. 
 
 Fistula Caused From Collar Sitfasts 
 
 There is a type of fistula that differs some- 
 what from those just described. It is located 
 in front of the generally accepted limits of the 
 withers proper, and it exhibits certain etiologic, 
 pathologic and clinical differences that call foi 
 a special description and which require differ- 
 ent methods of management. 
 
 This injury starts as a cutaneous collar le- 
 sion. It begins as a pressiu*e necrosis of the 
 skin alone but later involves first the pad of the 
 mane and then the funicular portion of the 
 ligamentum nucha? and even extends down- 
 ward into the lamellar portion, creating a very 
 troublesome condition to treat. 
 
 When observed in the early stage of devel 
 opment, the seat of the collar at the level of 
 the mane where the thick skin is folded trans- 
 versely into several deep undulations, is found 
 to contain a black, smooth, hairless^ leather- 
 like, circular zone of insensitive integument 
 that is loosened slightly from the viable skin 
 all ai'ound its circumference, but which can not 
 be lifted off. It is attached and although some 
 time is given for it to separate, no such an event 
 occurs. It remains stubbornly attached. At 
 
TREATMENT 101 
 
 first there is no swelling and the patient dis- 
 plays little discomfort, but later when the dead 
 tissues begin to putrefy and impregnate the 
 adjacent tissues with infections or serve as an 
 avenue of entrance into them, the subject be- 
 comes unfit to work with a collar, a certain 
 amount of discharge begins to appear around 
 its borders, and the subjacent musculature be- 
 comes swollen or bulges from the swollen lig- 
 aments within. Soon the slough which is a large 
 cone-shaped mass of skin and pad detaches 
 itself and can then be removed by blunt dis- 
 section, leaving a deep well whose bottom is 
 the ligamentum nuchge. Treated as an open 
 wound the cavity often closes up with nothing 
 more harmful than a slight deformity of the 
 neck which will vary according to the size of 
 the slough removed. 
 
 Many cases, however, do not behave so well. 
 Cicatrization of the cavity leaves a small fistu- 
 lous tract that runs down to and often under 
 the ligamentum nuch^e, and w^hich in spite of 
 local treatment continues to discharge consid- 
 erable ])us. The sides of the neck along the 
 ligament bulge slightly in both the forward and 
 the downward directions. This Ls fistula from 
 sitfast. Later if no relief is given the lamellar 
 portion becomes involved, at first only slightly 
 but later over a wider and wider zone until the 
 
102 FISTULA AND POLL-EVIL 
 
 whole lower third of the cervical region is hard 
 and tumefied. Abscesses may point well for- 
 ward along the neck and as far down as the 
 level of tlie vertebrge. This is cervical fistula, 
 a type that may also result from either the typ- 
 ical or the atypical types previously described. 
 The treatment of fistula from sitfast should 
 begin with prevention. That is to say, the sit- 
 fast should be properly managed. It is an 
 error to allow even the smallest superficial 
 sitfast to sojourn on the neck unchecked. The 
 veterinarian should recommend prompt extir- 
 pation and give warning about the serious state 
 that may develop from careless treatment 
 thereafter. The sitfast should be extirpated 
 down into the sound, unaffected tissues, no 
 matter how far it may extend, and the subject 
 must be removed from service or worked with 
 a breast collar. To leave any part of the dead 
 tissue in the cavity or to subject the neck to 
 continued injury by working the patient with 
 a collar will encourage the development of 
 chronic fistula and the attendant results. We 
 therefore advise that all sitfasts be managed 
 witli this end in view, that the patient be sub- 
 mitted to a proper operation and the wound 
 treated as it should be after the operation. The 
 extirpation of deep sitfasts and the application 
 of caustic into the cavity in our hands have not 
 
TREATMENT 103 
 
 been found to be good practice. We have de- 
 pended upon the completeness of the extkpa- 
 tion as the main treatment, and in order to 
 properly carry out this plan we have found 
 it necessary to place the patients in the re- 
 cumbent position with the neck well stretched 
 downward to expose the field to the best ad- 
 v^antage. Attempts to extirpate sitfasts of 
 this character in the standing position end in 
 failure to remove all of the dead elements. 
 With the head elevated, the skin folded, the 
 patient lunging about and the blood masking 
 the view, it is never possible to work accu- 
 rately, and a misdirected or incomplete extir- 
 pation is the result. 
 
 By placing the patient on the operating table 
 or down on the ground with ropes, the neck 
 can be drawn downward, the parts cleaned, 
 the blood well baled and the whole mass of 
 dead and unviable tissues can be cut away. 
 Prompt healing will then follow. 
 
 Once the fistula has formed it will be neces- 
 sary to operate promptly to prevent the spread 
 of the advancing inflammation into the lamel- 
 lar portion of the ligament. 
 
 We cast the patient clean and shave the neck 
 and then make an incision no less than eiQ'ht 
 inches long in the median line through the 
 skin, pad of the mane and down between the 
 
104 FISTULA AND POLL-EVIL 
 
 two halves of the hgament. Widening the 
 wound with the tumor forceps we then resect 
 as much of the ligament as is thought to be 
 diseased, making sure that the lowest limits of 
 the disease have been reached. In the average 
 case, not yet encroaching into the lamellar por- 
 tion, the bottom of the cavity is found just 
 under the funicular portion of the ligamnt. 
 The woimd is treated without drainage by 
 smothering it well with boric acid and iodoform 
 until cicatrization is well advanced. 
 
POLL-EVIL 
 
 The Poll 
 
 The poll or nape of the neck of quadrupeds 
 having a long highly mobile neck and large 
 head is an important region. Although less 
 complicated from the anatomical standpoint 
 than the withers it is nevertheless composed of 
 a great many separate anatomical structures 
 and although more shallow than the withers 
 its relations to the large nerve centers makes 
 affections of the poll more or less dreaded from 
 the view point of disease and of surgery. The 
 structures involved in poll-evil are contiguous 
 to the coverings -of the spinal cord in the 
 atlanto-axoid space, to the occipito-atlantoid 
 articulation and finally to the meminges and 
 the brain. It is plain that no chronic patholog- 
 ical process so serious as poll-evil can so- 
 journ unchecked without sooner or later im- 
 plicating some of these structures if not all of 
 them. The surgical anatomy of the withers 
 does not include a trochoid articulation and its 
 relations to the sjiinal cord are more remote. 
 
 The surgical anatomy of the poll includes, 
 the skin, the pad of the mane, the atlas, the 
 
106 FISTULA AND POLL-EVIL 
 
 axis, the occipital crest, the occipito-atlantoid 
 articulation the atlanto-axoid ligament, the 
 spinal cord, the funicular portion of the liga- 
 mentum nuchse, the musculature, the blood sup- 
 ply, the anterior end of the sj)inal cord the 
 meninges, the medulla oblongata, the spinal ac- 
 cessory nerve, and the first two spinal nerves. 
 
 The shin of the central line of the poll is 
 thick and inseparable from the thick pad of the 
 mane lying immediately beneath it. On the 
 sides of the mane it is thin, somewhat delicate 
 in texture, but possesses nothing out of the 
 ordinary to describe. On the sides, the borders 
 of the wing of the axis can be felt through it. 
 Elsewhere the outlines of the bones can be 
 palpated through it. In old cases of poll-evil 
 it is riddled with perforations and often it con- 
 tains scars of previous perforations. 
 
 TJie pad of the mane at the poll is very 
 heavy especially in the draft breeds of horses, 
 often exceeding two inches in thickness. In the 
 lighter breeds as for example the thorough- 
 breds it is thin and in some subjects it does not 
 exist. The pad here like that at the base of 
 the neck is composed of elastic tissue and fat 
 matted into a very firm structure homogeneous 
 in appearance, and always very vascular. 
 
 The atlas, or first cervical vertebra possesses 
 
POLL-EVIL 107 
 
 none of the characteristics of vertebrae in gen- 
 eral. It articulates by means of diarthrodial 
 articulations with the occipital condyles an- 
 teriorly and with the odontoid process of the 
 axis posteriorly. Its wide expansive dorsal 
 surface gives attachment to the muscles to 
 which it is related. 
 
 Its wings which extend downward and out- 
 ward become gradually thinner and thicken 
 again into a roughed heavy border. Each one 
 is perforated with a large foramen which gives 
 passage to the occipital artery, in its course 
 from the carotid to the region of the poll. 
 
 The whole dorsal face is a smooth expanse 
 interrupted only by a slight median elevation 
 representing the superior spinous process. 
 
 The dorsal surface of the atlas is important 
 in poll-evil because it sooner or later becomes 
 affected with periosteitis and osteitis on ac- 
 count of its close relations to the disease process 
 in and about the ligament um niich^. It 
 serves as a floor for the abscess cavity from 
 which it is often separated only by a carpet of 
 granulation tissue attached to the periosteum. 
 
 The axis or second cervical vertebra may be 
 said to be the posterior boundary of the poll- 
 evil process. It is seldom itself involved in 
 disease. Its crest or superior spinous process 
 stands above the level of the axis where it serves 
 
108 FISTULA AND POLL-EVIL 
 
 as a pillar for the ligamentum nuchas to bridge 
 over the space between it and the nuchal (oc- 
 cipital) crest. The ligamentum nuchse is, how- 
 ever, attached to it only by the lamellar por- 
 tion, which at this point is very thick. 
 
 Tlie nuchal {occipital) crest is a process of 
 the occipital bone extending upward to give 
 attachment to the ligamentum nuchee and to 
 the muscles of the poll. It has a rough border 
 and a somewhat concave posterior face which 
 is depressed at one point on each side of the 
 median line to receive each half of the ligament. 
 Its upper outlines determine the profile of the 
 space between the ears. 
 
 The compact tissue of the occipital crest is 
 dense and hard particularly along the summit. 
 The cells of the cancellated tissue are large and 
 the plates separating them are thin and there- 
 fore easily permeated with inflammatory proc- 
 esses. Although the occipital crest is not en- 
 croached upon by disease in poll-evil itself, it 
 sometimes becomes affected by a chronic os- 
 teitis from chiseling into it to effect drainage 
 as recommended by Williams. 
 
 The atlanto-acvoid ligament covers the gap 
 intervening dorsally between the anterior por- 
 tions of the axis and the posterior part of the 
 atlas. This space is about an inch and a half 
 to two inches long and about an inch wide, be- 
 
POLL-EVIL 109 
 
 neath which hes the spinal cord unprotected 
 by bony covering. Above the intervertebral 
 ligament there is a thick musculature and the 
 funicular portion of the ligamentum nuchse. 
 
 The occipito-atlantoid articulation is a diar- 
 throsis whose large capsular ligament is ar- 
 ranged to include both occipital condyles. It 
 is protected superiorly by muscles which also 
 separate it from the ligament laterally. 
 
 The atlantoid bursa — the initial seat of al- 
 most all poll-evils — lies between the ligamen- 
 tum nuchge and the dorsal arch of the atlas. 
 This bursa has no connection with the articu- 
 lation. 
 
 The spinal cord is exposed in two places to 
 both the disease and the operation against poll- 
 evil. It is, however, in the atlanto-axoid space 
 that it is most likely to be encroached upon. 
 The musculature covering it in the atlanto- 
 axoid space or the intervertebral ligament, is 
 usually the floor of the abscess cavity but some- 
 times these structures are degenerated and per- 
 forated in a downward direction until first the 
 meninges and later the cord becomes involved. 
 The cord exposure in the space is about one 
 and a half to two inches. The cord must also 
 be thought of when packing wound cavities 
 with hemostatic packs because its covering is 
 compressible and considerable spinal pressure 
 
no FISTULA AND POLL-EVIL 
 
 may be caused by wadding the cavity too tight. 
 
 The other place through which the spinal 
 cord becomes exposed is at the occipito-atlant- 
 oid articulation. Here it is attacked by en- 
 croaching disease after the capsule of the joint 
 has been invaded. 
 
 The ligamenUimi nuchse is a powerful, elas- 
 tic apparatus, the principal function of which 
 is to assist the extensor muscles of the head and 
 neck. It extends from the occipital bone to 
 the withers, where it is directly continuous with 
 the supraspinous ligament. It consists of two 
 parts, funicular and lamellar. 
 
 The funicular part arises from the external 
 occipital protuberance and the fossa below it 
 and is inserted into the summits of the verte- 
 bral spines at the withers. — Sisson. 
 
 It is between the funicular portion of this 
 ligament and the dorsal arch of the atlas that 
 the bursa (supra-atloid) lies. At the pole the 
 funicular part consists of two bands closely at- 
 tached to each other. The lamellar portion of 
 the ligamentum nuchas is not attached to the 
 atlas, but begins at the axis to which a ver} 
 tliick and strong digitation is attached. 
 
 Ohliqmis Cajntis Antcfior. This is a short, 
 flat and nearly square muscle, having tendin- 
 ous intersections. It originates from the an- 
 terior edge and, ventral siu'face of the wing of 
 
POLL-EVIL 111 
 
 the atlas inserts to the parmastoid process 
 nuchal (occipital) crest and the mastoid pro- 
 cess. 
 
 Obliquus Capitis Posterior (Posticus) . This 
 muscle lies upon the dorsolateral aspect of the 
 atlas and axis. It is broad, flat, thick and 
 fleshy. Its origin is from the side of the spine 
 and the posterior articular process of the axis. 
 It inserts to the dorsal surface of the wing of 
 the atlas. Its function is chiefly to rotate the 
 atlas, and by this means, the head. 
 
 Rectus Capitis Dorsalis Major, This mus- 
 cle originates from the edge of the spinous 
 process of the axis and inserts to the occipital 
 bone, below the tendon of insertion of the com- 
 plexus. It is in contact with the ligamentum 
 nuchse. 
 
 Rectus Capitis Dorsalis Minor. This is 2 
 small muscle which lies under the rectus cap- 
 itis dorsalis major. It originates from the 
 dorsal surface of the atlas and inserts to the 
 occipital bone beneath the point of insertion of 
 the last named muscle. It is lateral to the 
 cordiform portion of the ligamentum nuch^. 
 
 Rectus Capit us Ventralis (Auticus) Major, 
 This, the long flexor muscle of the head has its 
 origin posteriorly from the transverse process- 
 es of the third, fourth and fifth cervical verte- 
 
112 FISTULA AND POLL-EVIL 
 
 brae. It inserts to tubercles which occur at 
 the junction of the basilar part of the occipital 
 bone with the body of the sphenoid. These 
 muscles (the pair) may be said to form a roof 
 for a part of the pharynx. 
 
 The blood supply of the poll is from three 
 sources: The occipital, the superior cervical 
 and the vertebral arteries. The first named 
 is, however, the chief one. It is a radical of 
 the carotid and passes to the region of the poll 
 through the large foramen in the wing of the 
 atlas. Its branches anastomose with the other 
 two. The branches are numerous and often 
 through the influence of the disease become 
 greatly enlarged. In the operation for poll- 
 evil the incision being a standard one, made 
 irrespective of blood vessels, there is nothing of 
 importance to say about avoiding them, ex- 
 cept that lateral invasion into the region of the 
 alar foramen through which the occipital passes 
 must be made cautiously. In short, no especial 
 effort except this one, is ever made to avoid 
 arteries. 
 
 The 7ierve supply is of no especial impor- 
 tance. It is derived from the spinal accessory 
 and the first two spinal nerves, none of which 
 is ever seen in the operation, nor is a solution 
 on the continuity of their branches attended 
 with anv observable harm. 
 
PATHOGENESIS 
 
 Poll-evil, like fistula of the withers, we di- 
 vide into two classes : typical and atypical. By 
 typical poll-evil we mean those cases that de- 
 velop independent of any known cause in the 
 atlantoid bursa, just as fistula of the withers so 
 frequently develops in the dorsal bursa. By 
 atypical poll-evil — a rare entity — we designate 
 those that originate from abrasions or wounds. 
 The former invade outward while the latter in- 
 vade inward from the initial seat. 
 
 The course of all typical poll-evil we divide 
 into three stages : the saccular stage, the phleg- 
 monous stage and the fistulous stage, as in fis- 
 tula of the withers. 
 
 The saccular stage begins in the form of a 
 distension of the atlantoid bursa with a sero- 
 fibrinous fluid that is sterile and whose influ- 
 ence causes the formation of a well defined 
 membranous wall composed of a cellular inter- 
 nal face fortified by fibrous tissue. As the les- 
 ion becomes older the fibrous tissue becomes 
 more abundant, sometimes amounting to an 
 extensive fibrosis of the surrounding muscula- 
 ture. The sac may bulge on one or both sides 
 and may be small or large enough to conspicu- 
 
114 FISTULA AND POLL-EVIL 
 
 ously deform the region. Being imbedded un- 
 der firm tissues, it is often hard to the touch, 
 fluctuating only after pushing its way to the 
 surface on the side of the hgamentum nuchge 
 and pad of the mane. Evacuating the contents 
 of the sac during this stage yields an amber 
 colored fluid carrying coagulated detritus con- 
 taining no bacteria. 
 
 This sac may sojourn indefinitely and may 
 even for a time seem to disappear entirely, only 
 to reappear subsequently. 
 
 Evacuation and careful attention to the 
 tract and cavity may sometimes end the pro- 
 cess by slow cicatrization. Thus sometimes a 
 poll-evil is cured without a radical operation. 
 In most cases, however, the invasion of the 
 tract and cavity with extraneous microbes 
 ends in chronic fistula. 
 
 The plilegmonous stage. In the usual course 
 of events the saccular stage ends in infection of 
 the cavity. The manner in which microorgan- 
 ism gains access to the cavity is not known, 
 but the frequency with which poll-evil is asso- 
 ciated with strangles and influenza has led us 
 to believe that these diseases play an important 
 role in its etiology ; the affected atlantoid bursa 
 serving as a focus of localization for microor- 
 ganisms contained in the blood after these dis- 
 eases. 
 
PATHOGENESIS 115 
 
 During this stage the patient becomes sick 
 and severeh^ hindered in the movements of the 
 head. It becomes manifestly opisthotonic in 
 attitude, and develops a body temperature of 
 from two to three degrees above normal. The 
 poll becomes progressively more painful to the 
 touch and the sides of the neck are streaked 
 with radiating lines. 
 
 The Fistulous Stage 
 
 Either by lancing or by spontaneous ripping 
 and bursting of the abscess this stage sooner or 
 later passes into the stage of chronic discharge 
 — fistula. If the infection is not a virulent one 
 the development is very slow — cold abscess — 
 and fibrosis becomes a prominent feature of the 
 process. That is to say, if the accumulating 
 pus is not released the process reacts upon the 
 surroundings in some way that causes the mus- 
 cular elements to become fibrous. 
 
 The fistulous and the phelgmonous stages 
 are of course influenced by microorganism. 
 These exert a more or less destructive influence 
 upon the ligamentum nuch«, which is in the 
 center of the theater of attack. Once this fibro- 
 elastic structure has been damaged it acts as 
 the underlying cause of subsequent pathologic 
 processes. Riddled with perforations, shred- 
 ded with bundles of its fibers which remain 
 
116 FISTULA AND POLL-EVIL 
 
 stubbornly attached, and carpeted here and 
 there with dormant granulations it prevents 
 cicatrization of the abscess cavity. It is this 
 stubborn viability of the ligamentum nuchse 
 that is responsible for the chronicity of poll- 
 evil. 
 
 This stage, like that of fistula of the with- 
 ers, continues indefinitely, healing at one place 
 and bursting at another and all of the while 
 transforming the muscles into fibrous tissue. 
 The inflammatory process extends into the per- 
 iosteum of the atlas, into the capsule of the oc- 
 cipito-atlantoid articulation, into the meninges 
 and brain, into the neural canal and into the 
 spinal cord, producing the variety of comph- 
 cations for which poll-evil is known. 
 
 An old poll-evil left to sojourn unmolested 
 or one indifferently treated usually exhibits 
 the following morbid states: a tumefied poll, 
 one or more apertures discharging pus, scars 
 of previous apertures, encrustations of dried 
 pus matted into the mane and surrounding 
 hairs, extended head from fibrous anchylosis 
 of the occipito-atlantoid articulation and a wab- 
 bly gait that becomes more and more accentu- 
 ated until the patient is unable to rise. Sec- 
 tioned, the poll is foimd to have been trans- 
 formed into a mass of hard, fibrous tissue, 
 which fuses all of the component structures in- 
 
PATHOGENESIS 117 
 
 to one homogenous mass. This mass is riddled 
 with tracts and under the now unrecognizable 
 hgamentum nucha is an abscess cavity almost 
 closed by granulation tissue. The surface of 
 the atlas is rough from destruction of its peri- 
 osteum and it may be studded by numerous 
 vegetations of bony growths. There is found 
 sometimes a shredded condition of parts of the 
 ligament, parts that have partly loosened from 
 necrosis. In some cases, usually in aged horses, 
 the hgament is permeated with calcareous de- 
 posits, each of which is well incarcerated with 
 connective tissue elements. 
 
 Atypical Poll-Evil 
 
 The atypical poll-evil begins with a halter 
 abrasion of some kind of wound that 
 gives admission to pyogenic microorganisms. 
 It is at first a subcutaneous abscess, 
 and if carbuncular in character may give 
 rise to all of the symptoms of a typical 
 poll-evil in the phlegmonous stage. This 
 form will differ from the typical form in 
 that cicatrization will follow evacuation of its 
 pus and general slough. If deep and the 
 slough should be attached to the ligamentum 
 nuch^e a chronic poll-evil having all of the char- 
 acteristics of the other, the typical kind, will 
 supervene. In this case the ligament is at- 
 
118 FISTULA AND POLL-EVIL 
 
 tacked from without. Its dorsal face is at- 
 tack first, while in the other, the under part 
 at the atlantal bursa, is attacked before the 
 upper part becomes involved. 
 
 This form of fistula can only be recognized 
 as such at the early stage, for once spread 
 deeply into the poll it has no differentiating 
 qualities. 
 
 Etiology 
 
 The cause of poll-evil, like that of fistula of 
 the withers, is by no means settled. The aca- 
 demic explanation (traumatism) that seems to 
 have satisfied all past writers on the subject 
 entirely lacks confirmation. Wherever this 
 subject is discussed verbally or in literature the 
 matter of etiology is always indifferently 
 passed over as if it is a settled fact that poll- 
 evil is a traumatism. No one seems to have 
 ever questioned seriously the theory of trau- 
 matic origin in spite of the fact that no one 
 seems to have ever actually traced a typical 
 poll-evil to any definite traumatism. The 
 truth seems to be that traumatism plays no 
 part whatever in its cause. Except in the rare 
 case that originates with a wound of the poll 
 it is plain that we must seek farther for a rea- 
 sonable theory of cause. It is our opinion that 
 the cause is unknown, that the serous sac that 
 starts it develops under influences we cannot 
 
PATHOGENESIS 119 
 
 explain at the present time. We believe, how- 
 ever, that infectious diseases such as influenza 
 or strangles play an important role in the 
 course if not also in the original cause. Where 
 influenza is rampant so will poll-evil and fis- 
 tula of the withers be found rampant. We are, 
 however, not today justified as laying this 
 down as an absolute law, as subsequent inves- 
 tigations no doubt may show that its cause 
 is more specific. 
 
SYMPTOMS 
 
 Typical poll-evil is first seen as a slight bulg- 
 ing of one or both sides of the poll. There are 
 at first no manifestations of pain either on pal- 
 pation or in movements of the head. Later as 
 the phlegmonous stage begins the movements 
 of the head become painful and palpations an- 
 noy the patient. Some will oppose any at- 
 tempt to touch the region. Before the abscess 
 points there are radiating lines along the sides 
 of the neck. The head is held extended, later- 
 al movements are painful and the whole body 
 is turned stiffly, as if tlie whole axial skeleton 
 were anchylosed. 
 
 Later the abscess points and discharges its 
 contents over the sides of the neck. The aper- 
 ture may then discharge a limited quantity of 
 pus for weeks that keeps the region continual- 
 ly soiled and irritated. The aperture will fin- 
 ally close gradually as the discharges become 
 less abundant, but this will eventually be fol- 
 lowed by the forming of another abscess, which 
 will behave in the same manner as the preced- 
 ing one, and so the condition proceeds. While 
 these abscesses and tracts are forming, the mus- 
 culatm'e involved becomes considerably elevat- 
 
122 FISTULA AND POLL-EVIL 
 
 ed above the surrounding level. The head, at 
 first extended from the pain of the forming ab- 
 scesses, gradually becomes fixed in the extend- 
 ed position from fibrous anchylosis of the re- 
 gion. An animal affected with poll-evil has a 
 characteristic attitude simulating the opisthot- 
 onos of tetanus. 
 
 Poll-evil that becomes infected before there 
 is an}^ enlargement of the region must be diag- 
 nosed sometimes entirely from this attitude 
 and from the pain produced by manipulating 
 the head. 
 
 Rare cases cause epiliptiform seizures when 
 the head is moved about manually or in work- 
 ing. In such instances when local evidence is 
 entirely lacking because of the depth of the 
 infected focus it may not be an easy matter to 
 arrive at a diagnosis. 
 
 The development of poll-evil is always grad- 
 ual, although it may often assume considerable 
 projDortions before attracting attention. The 
 mane and forelock shelter the region so effec- 
 tually in some animals that the enlargement 
 develops unnoticed until discharges appear. 
 These cases are, however, rare, as the pain and 
 the position of the head which precede the dis- 
 charge are usually pronounced enough to at- 
 tract attention. 
 
 The average poll-evil when submitted to the 
 
SYMPTOMS 123 
 
 veterinarian is either found as an enlargement 
 on one or both sides of the poll or else as a sup- 
 purative condition that matts the hairs of the 
 mane and soils the region with dried pus. 
 
 As the disease progresses the patient be- 
 comes distinctly unthrifty in appearance and 
 loses flesh. Locomotion is slow. The patient 
 gropes about and trots only w^hen urged. Feed- 
 ing from the bottom of the manger and grazing 
 is painful. 
 
 Later, as nervous complications develop, the 
 hind quarters wabble inordinately and rising 
 becomes more and more difficult. Finally the 
 failing subject, unable to stand, dies from de- 
 cubital complications, if it is not sooner killed 
 to end its misery. 
 
 Complications 
 
 Paralysis. — The most serious complication 
 is paralysis due to advancement of the inflam- 
 matory process into the meninges, the cord and 
 even the brain itself. The invasion is usually 
 at the atlanto-axoid space, but sometimes oc- 
 curs through the occipito-atlantoid articulation. 
 When these nervous structures become in- 
 volved early in the progress of the disease, the 
 case is not necessarily a hopeless one because 
 of the nerve involvement, since an operation 
 which evacuates the pus externally may turn 
 
124 FISTULA AND POLL-EVIL 
 
 the tide of the inflammatory process towards 
 resolution. On the other hand, if nervous com- 
 plications develop as a phase of later stages, 
 the case is always hopeless. The practitioner 
 is warned against operating upon such cases, 
 because the operation is always blamed for the 
 unfavorable termination, and in fact rightly 
 so, since the advancement of the process into 
 the cord and brain is accentuated rather than 
 retarded by surgical treatment at this stage of 
 the development. And besides, patients thus 
 stricken are unable to withstand the enfeebling 
 influence of such a major operation. 
 
 Involvement of the Occipito-Atlantoid Ar- 
 ticulation. — Lying adjacent to the initial focus 
 of the disease, this joint very often becomes 
 infected within its capsular ligament at an 
 early stage. As a rule, however, this compli- 
 cation features later stages, the joint becoming 
 involved gradually through the medium of the 
 atlas. The periosteum and then the bone, 
 soaked with pus develop chronic inflammation 
 that advances into the joint through the articu- 
 lar cartilage. When this occurs it is only a 
 matter of weeks before serious results ensue 
 through involvement of the meninges. The 
 subject thus affected is in sore straits from the 
 severe pain it suffers, especially in moving the 
 head. 
 
SYMPTOMS 125 
 
 This complication is one of the common 
 causes of recurrences and failures of operative 
 treatment. It is incurable and if known to 
 exist should be regarded as a contra-indication 
 of the radical operation now universally recom- 
 mended for poll-evil. 
 
 Secondary Abscesses. — Although there are 
 fewer recesses and lamellar spaces for pus to 
 burrow into about the poll than there are about 
 the withers, there are, nevertheless, places 
 where pus will escape from the immediate re- 
 gion of the seat of poll-evil and cause secondary 
 abscesses. The common one that occurs both 
 before and after operating, localized at some 
 point of the neck along the ligamentum nuchge. 
 We have observed cases in which tracts extend- 
 ed down the ligament as far as the base of the 
 neck, the route followed being the space be- 
 tween the cervical muscles and the lamellar 
 portion of the ligaments just under the fu- 
 nicular portion. Most of these abscesses, how- 
 ever, localize at the level of the axis, where they 
 sometimes produce a stubborn condition to 
 handle by implicating the lamellar portion of 
 the ligament at that point. 
 
 Another focus of abscess formation is the 
 space between the anterior part of the v»ing 
 of the atlas and the styloid process of the oc- 
 cipital. This complication is disclosed at the 
 
126 FISTULA AND POLL-EVIL 
 
 time of the operation. After the ligament has 
 been removed, a sound can sometimes be passed 
 downward five or six inches before it touches 
 the bottom of the cavity. 
 
 Chronic Septicemia co-exists to a certain ex- 
 tent in all bad cases of poll-evil. It is, however, 
 less serious than in fistula of the withers, since 
 the region is smaller. 
 
TREATMENT 
 
 Xo time should be lost in submitting a poll- 
 evil to radical treatment. The new case 
 should be lanced and the cavities irrigated 
 with antiseptics for a week or ten days and 
 then promptly operated upon. There will be 
 nothing gained by waiting longer, as the old- 
 er the case the more it will have damaged the 
 structures of the region and thus the more diffi- 
 cult it will be to cure. In cases found in the 
 phlegmonous stage and before the abscess has 
 burst we also recommend lancing and irriga- 
 tions as preparatory treatment. 
 
 Subjects having unmistakable involvement 
 of the occipito-atlantoid articulation and all 
 those already showing nervous complications 
 should be left severely alone and pronounced 
 incurable. Weak subjects that do not exhibit 
 sufficient strength to withstand a major opera- 
 tion should likewise be left alone. These might, 
 however, be submitted to a restorative treat- 
 ment until it is thought advisable to interfere 
 fiu-ther. 
 
 The Radical Operation for Poll-Evil 
 
 Restraint. — Xo attempt should ever be made 
 to operate in the standing position, no matter 
 
128 FISTULA AND POLL-EVIL 
 
 how tractable the patient may seem. Opera- 
 tions performed in the standing position under 
 some form of narcosis always turn out to be 
 very unsurgical exhibitions. The patient should 
 be cast with ropes or else placed upon an op- 
 erating table. The latter is much the best be- 
 cause of the elevated position of the head. On 
 the floor or ground the field is not so accessible 
 and must be elevated by blocking the neck and 
 head up in some way to bring it where the sur- 
 geon can work. Chloroformed, the patient can 
 be handled better than under narcosis. When 
 rope restraint is used chloroform should really 
 be administered because it is difficult to control 
 the sweeping movements of the head of a par- 
 tially anesthetized subject down on the ground. 
 Our plan in field work is to clean up the poll 
 well while the subject is standing, cast with 
 ropes, administer chloroform and then block 
 up the neck and poll with a tightly filled sac of 
 straw. This sac may be bound to the neck and 
 head with cords, one around the middle of the 
 cervical region and one around the head just 
 below the eyes. Thus tied the blocking will 
 stay in place when the neck and head move. 
 This form of blocking is particularly essential 
 when the operation is done on the ground un- 
 der narcosis. It is important that the sac be 
 well filled, otherwise it will flatten down and do 
 
TREATMENT 12^ 
 
 no good. For this purpose we also use when 
 available two or three buggy or automobile seat 
 cushions. 
 
 The head should be maintained at about its 
 normal angle with the neck. Extreme ex- 
 tension or flexion is undesirable. 
 
 The patient should lie on its right side. Al- 
 though this is not mandatory, the surgeon finds 
 that it is easier to cut backward with the right 
 hand when the patient is thus positioned. 
 
 Incision. First Step. — The scalpel is pushed 
 carefully downward, with its cutting surface 
 backward, just behind the occipital crest in 
 the very middle of the neck, until it either en- 
 ters the bursa or is blocked by the occipital 
 bone. Its blade should be buried about four 
 inches in the average case. It is then drawn 
 backward, maintaining this depth, about eight 
 inches. If a longer incision is decided upon it 
 is best to make it more shallow posteriorly be- 
 cause of the danger of invading the neural 
 canal. If a short bladed scalpel is used several 
 strokes will be required. Blood will flow cop- 
 iously from many sources, but no attempt is 
 made to control it either by ligation or forceps. 
 It is our experience that more blood is lost 
 when the operation is stopped to make these 
 attempts at hemostasia. We, however, grasp 
 
130 
 
 FISTULA AND POLL-EVIL 
 
 each edge of the wound with a tumor forceps 
 give one to the assistant and hold the other in 
 the left hand. By drawing hard on these the 
 
 Fig. 13. — Poll Evil Showinc I^eformity Due to the 
 Treatment With Caustics. 
 
 bleeding will he controlled to some extent. 
 
 Separating the ligament from the occipital 
 
 Crest. Second Step, — This to us is the most 
 
TREATMENT 131 
 
 important part of the operation, as it supplies 
 the first "landmark" for the subsequent resec- 
 tion. Those who ignore this step will find it 
 
 Fig. 14. — A Recl'rf^ext Cask After Temporizing Treatment, 
 Note the scars from lateral incisions through which drain- 
 age had 1)een attempted. 
 
 difficult to locate the ligament and will often 
 abandon the work without having accomplished 
 
132 FISTULA AND POLL-EVIL 
 
 the main object — the resection of the hgament. 
 
 In this step we lay the scalpel aside and take 
 up the probe-pointed bistoury. We first pass 
 the index finger of the right hand under the 
 hgament right at the crest and using the finger 
 as a guide pass the bistoury under it, cutting- 
 outward and upward. The ligament through 
 its extreme elasticity will contract backwards 
 as fast as it is cut and tlius reveal itself to the 
 operator. That is, the end will come right out 
 into the foreground after contracting back- 
 ward an inch or more. We then grasp the end 
 with a tumor forcep and dissect it in the back- 
 ward direction as it is drawn upon with the for- 
 cep. Over the region most badly damaged by 
 disease it will be found so fused with the other 
 connective elements that it can not be said to 
 be a distinct structure. We attempt to take 
 away as much of this connective tissue as is 
 thought prudent as the dissection proceeds 
 backward. The dissection is continued along 
 the whole length of the incision or until the 
 sound part of the ligament is reached posteri- 
 orly. We know when the sound part is reached 
 by its elasticity. When the section now held in 
 the forcep is drawn back and forth the liga- 
 ment it seen to stretch easily. Here it is cut 
 off. 
 
 The attention is now directed to the other 
 
TREATMENT 
 
 133 
 
 side, as this removes only one-half of the liga- 
 ment. The operation must be repeated in the 
 same way on the opposite side. Allowance 
 must be made for a possible sectioning of the 
 ligament into two unequal parts when the first 
 
 
 
 
 k 
 
 Fig. 15. — The Operation Completed. 
 Note that the operative wound is packed so tightly that the 
 poll appears swollen even more than before the operation. 
 Note also the enlargement of the lymphatics of the neck, due 
 to the absorption of toxic materials from the suppurating 
 area. 
 
 incision was made. That is to say, when the 
 scalpel was drawn backward in making the in- 
 cision it may not have traveled exactly be- 
 tween the two lateral halves of the ligament 
 and thus has left more to be removed from 
 
134 FISTULA AND POLL-EVIL 
 
 one side than from the other. Sometimes in 
 misdirected plunges of the scalpel into the poll 
 the ligament may all be left on one side, some- 
 times two-thirds is on one side and one-third 
 on the other, etc. And again, if the incision 
 was not made straight there may be more liga- 
 ment anteriorly than posteriorly on a given 
 side. These are points to keep in mind at all 
 times. The point is to remove all of it along 
 the affected zone, but no more than is necessary 
 posteriorly. 
 
 Packing and Suturing. Third Step. — The 
 w^ound is now wadded with a hemostatic pack 
 of oakum and sutured securely. We make no 
 attempt to wad the cavity so very tight posteri- 
 orly on account of the danger of spinal pres- 
 sure, although it must be well filled. The ob- 
 ject in making a safe hemostatic pack for poll- 
 evil is to distribute the pressure evenly over 
 the whole cavity. That is, severe pressure from 
 hard lumps of the oakum must be avoided, es- 
 pecially at the posterior end of the wound. 
 iWhen the patient is standing again the poll 
 and bloody neck are washed off with liberal 
 ablutions of water and then the poll is covered 
 w^ith a layer of oakum or cotton soaked in mer- 
 curic chlorid solution and this is held in place 
 Avith a hood made from muslin or common bur- 
 lap. 
 
TREATMENT 135 
 
 After-care. — At the end of twenty-four 
 hours the sutures are removed and the packing 
 carefully lifted out. Harsh handling will cause 
 bleeding and should be avoided at this early 
 moment after the operation. We simply fill 
 the cavity with a cotton wadding dripping with 
 mercuric chlorid solution and replace the hood 
 for another twenty- four hours before attempt- 
 ing any systemic after-treatment. 
 
 The subsequent after-care consists of smoth- 
 ering the w^ound secretions by the application 
 of abundance of boric acid and iodoform in the 
 proportion of 95 to 5. This should be applied 
 three times a day for the first five days and 
 later twice and still later once a day. 
 
 Healing is usually complete in forty days. 
 
 Accidents and Sequelae 
 
 Hemorrhage is a common enough accident 
 of poll-evil. Always copious, it assumes seri- 
 ous proportions when the operation is in any 
 way delayed. When the anesthesia or the 
 restraint miscarries serious blood losses always 
 occur. Secondary hemorrhage is rare except 
 when the cavity is too hashly handled when 
 the packing is first removed. 
 
 The hemostasia of poll-evil operations lies 
 in: 
 
 1. Stretching the wound apart forcibly 
 
136 FISTULA AND POLL-EVIL 
 
 with the tumor forcep as soon as the incision 
 is made. 
 
 2. Performing the operation without delay. 
 
 3. Packing the wound with an even pres- 
 sure with oakum securely retained with su- 
 tures. 
 
 4. Avoiding harsh handling until at least 
 forty-eight hours have elapsed. 
 
 Paralijsis. — We have had animals become 
 entirely paralyzed after poll-evil operations, 
 due to having attempted to cure incurable 
 cases already having nervous complications, 
 but aside from those it is always possible, when 
 due care is not taken to properly attend to such 
 a large wound adjacent to the neural canal, 
 for the inflammatory process to invade through 
 the muscles covering the atlanto-axoid space 
 and produce trouble that did not previously 
 exist. Then again, undue pressure of a lumpy 
 hemostatic pack is always a hazard. By avoid- 
 ing operations on subjects exhibiting a wabbly 
 gait, carefully packing the wound and then 
 properly caring for it afterward there is little 
 danger from this complication. 
 
 Slough of the Distal Stump of the Liga- 
 ment Nuchae, — Failure of the wound to heal 
 at the posterior commissure is due always to 
 a slough of the stump of the ligament. Some- 
 times the slough is small and at other times it 
 
TREATMENT 137 
 
 is large. This sequel is manifested in two 
 ways. In some cases the wound heals every- 
 where except at the posterior end, where a 
 small fistulous tract remains. Probed it is 
 found to be deep. If forceps are introduced 
 the slough can usually be taken hold of and 
 drawn out. Sometimes the aperture must first 
 be enlarged. 
 
 The other manifestation is the appearance 
 of a new phlegmonous condition on each side 
 of the neck just behind and below the posterior 
 end of the wound. The abcess is sometimes 
 threatening and unless properly handled may 
 end in a new fistulous condition quite difficult 
 to handle. The first sign of such a complica- 
 tion, w^hich usually occurs at about thirty-five 
 to forty days after the operation, must be met 
 by making an incision at the posterior end of 
 the old wound downward into the abcess cav- 
 ity, where a slough of the stump of the liga- 
 ment is always awaiting removal. 
 
 It is our practice to make a careful examina- 
 tion of the wound at the end of thirty days 
 with a view of determining whether or not such 
 a slough exists, and to remove it if found. 
 
 Recurrences and Failures 
 
 The failures from the radical operation for 
 poll-evil are almost always due to procrastina- 
 
138 FISTULA AND POLL-EVIL 
 
 tion. The disease being left to effect incurable 
 damage to the bones, particularly to the occipi- 
 to-atloid articulation, can not be cured entirely 
 by simply resecting the ligament. Wh^re the 
 ligament is removed early failures are negligi- 
 ble. Recurrences are due to sloughs of the diis- 
 tal stump referred to above or to failure to 
 remove all of the ligament. 
 
 By avoiding old incurable cases, by resorting 
 to effectual restraint and anesthesia, by op- 
 erating deliberately and without delay, by at- 
 tending skillfully to the wound and by keeping 
 in mind the slough of the distal stump, the iro- 
 ical operation for poll-evil is attended '*'/h i 
 few failures. It should be a routine measi .f; 
 with every veterinary practitioner. 
 
 And what is writ is writ; 
 
 Would that it were worthier. — Homer. 
 
 THE END 
 
Webster Family Library ol Veterinary IVIedicine 
 Cummings School of Veterinaiy Medicine at 
 Tufts University 
 
 Or{f\ \A/pcthnm RnaH