The original text was inconsistent in the use of accents and hyphenation. These variants and a small number of typographical errors were maintained in this transcription. A complete list of the variant spellings is found at the end of the book along with the list of typographical errors.
The Table of Contents lists the Authorities Cited section as preceding the Index, but it was printed following the Index. This order has been retained in this transcription.
Veterinary Practitioners' Series
LAMENESS OF THE HORSE
J. V. Lacroix, D.V.S.
Professor of Surgery, The Kansas City Veterinary College Author of "Animal Castration"
Chicago American Journal Of Veterinary Medicine
All that can be known on the subject of lameness, is founded on a knowledge of anatomy and of the physiology of locomotion. Without such knowledge, no one can master the principles of the diagnosis of lameness. However, it must be assumed that the readers are informed on these subjects, as it is impossible to include this fundamental instruction in a work so brief as this one.
The technic of certain operative or corrective procedures, has been described at length only where such methods are not generally employed. Where there is no departure from the usual methods, treatment that is essentially within the domain of surgery or practice is not given in specific detail.
Realizing the need for a treatise in the English language dealing with diagnosis and treatment of lameness, the author undertook the preparation of this manuscript. That the difficulties of depicting by means of word-pictures, the symptoms evinced in baffling cases of lameness, presented themselves in due course of writing, it is needless to say.
It is hoped that this volume will serve its readers to the end that the handling of cases of lameness will become a more satisfactory and successful part of their work; that both the practitioner and his clients may profit thereby; and last but by no means least, that the horse, which has given such incalculable service to mankind and is deserving of a more concrete reward, will be benefited by the application of the principles herein outlined.
In addition to the consultation of standard works bearing on various phases of the subject of lameness, the author wishes to thankfully acknowledge helpful advice and assistance received from the publisher, Dr. D.M. Campbell; to appreciatively credit Drs. L.A. Merillat, A. Trickett and F.F. Brown for valuable suggestions given from time to time. Particular acknowledgment is made to Dr. Septimus Sisson, author, and W.B. Saunders & Co., publishers of The Anatomy of Domestic Animals, for permission to use a number of illustrations from that work.
Chicago, Illinois, October, 1916.
Justice shows a triumphant face at the works of humane practitioners, who give serious thought and expend honest effort, for the alleviation of animal suffering.
TABLE OF CONTENTS
Page Illustrations 7 Introduction 11
Etiology and Occurrence 15 Affections of Bones 15 Rarefying Osteitis, or Degenerative Changes 16 Fractures 16 Affections of Ligaments 20 Luxations—Dislocations 21 Arthritis 22 Affections of Bursae and Thecae 27 Affections of Muscles and Tendons 28 Affections of Nerves 30 Affections of Blood Vessels 31 Affections of Lymph Vessels and Glands 32 Affections of the Feet 34
Diagnostic Principles 37 Anamnesis 38 Visual Examination 39 Attitude of the Subject 41 Examination by Palpation 43 Passive Movements 47 Observing the Character of the Gait 48 Special Methods of Examination 53
SECTION III Lameness in the Fore Leg
Anatomo-Physiological Review of Parts of the Fore Leg 55 Shoulder Lameness 61 Fracture of the Scapula 62 Scapulohumeral Arthritis 65 Infectious Arthritis 66 Injuries 66 Wounds 67 Luxation of the Scapulohumeral Joint 67 Inflammation of the Bicipital Bursa 68 Contusions of the Triceps Brachii 71 Shoulder Atrophy (Sweeny) 73 Paralysis of the Suprascapular Nerve 75 Radial Paralysis 77 Thrombosis of the Brachial Artery 81 Fracture of the Humerus 82 Inflammation of the Elbow 84 Fracture of the Ulna 86 Fracture of the Radius 87 Wounds of the Anterior Brachial Region 90 Inflammation and Contraction of the Carpal Flexors 93 Fracture and Luxation of the Carpal Bones 96 Carpitis 98 Open Carpal Joint 100 Thecitis and Bursitis 104 Fracture of the Metacarpus 106 Splints 107 Open Fetlock Joint 110 Phalangeal Exostosis (Ringbone) 118 Open Sheath of the Flexors of the Phalanges 124 Luxation of the Fetlock Joint 125 Sesamoiditis 127 Fracture of the Proximal Sesamoids 128 Inflammation of the Posterior Ligaments of the Pastern Proximal Interphalangeal Joint 129 Fracture of the First and Second Phalanges 131 Tendinitis (Inflammation of the Flexor Tendons) 135 Chronic Tendinitis and Contraction of the Flexor Tendons 137 Contracted Tendons of Foals 143 Rupture of the Flexor Tendons and Suspensory Ligament 146 Thecitis and Bursitis in the Fetlock Region 150 Arthritis of the Fetlock Joint 152 Ossification of the Cartilages of the Third Phalanx 155 Navicular Disease 157 Laminitis 160 Calk Wounds (Paronychia) 170 Corns 172 Quittor 174 Nail Punctures 178
SECTION IV Lameness in the Hind Leg
Anatomo-Physiological Consideration of the Pelvic Limbs 185 Hip Lameness 195 Fractures of the Pelvic Bones 196 Fractures of the Femur 199 Luxation of the Femur 201 Gluteal Tendo-Synovitis 203 Paralysis of the Hind Leg 204 Paralysis of the Femoral (Crural) Nerve 204 Paralysis of the Obturator Nerve 206 Paralysis of the Sciatic Nerve 208 Iliac Thrombosis 209 Fracture of the Patella 212 Luxation of the Patella 213 Chronic Gonitis 217 Open Stifle Joint 220 Fracture of the Tibia 222 Rupture and Wounds of the Tendo Achillis 224 Spring-Halt (String-Halt) 225 Open Tarsal Joint 229 Fracture of the Fibular Tarsal Bone (Calcaneum) 230 Tarsal Sprains 232 Curb 233 Spavin (Bone Spavin) 235 Distension of the Tarsal Joint Capsule (Bog Spavin) 242 Distension of the Tarsal Sheath of the Deep Digital Flexor (Thoroughpin) 246 Capped Hock 251 Rupture and Division of the Long Digital Extensor (Extensor Pedis) 253 Wounds from Interfering 255 Lymphangitis 257 Authorities Cited 265 Index 267
Page Fig. 1—Hoof Testers 53 Fig. 2—Muscles of Left Thoracic Limb, Lateral View 56 Fig. 3—Muscles of Left Thoracic Limb, Medial View 57 Fig. 4—Sagital Section of Digit and Distal Part of Metacarpus 59 Fig. 5—Ordinary Type of Heavy Sling 62 Fig. 6—A Sling Made in Two Parts 63 Fig. 7—Paralysis of the Suprascapular Nerve of Left Shoulder 76 Fig. 8—Radial Paralysis 78 Fig. 9—Merillat's Method of Fixing Carpus in Radial Paralysis 79 Fig. 10—Contraction of Carpal Flexors, "Knee Sprung" 95 Fig. 11—Pericarpal Inflammation and Enlargement Due to Injury 99 Fig. 12—Hygromatous Condition of the Right Carpus 100 Fig. 13—Carpal Exostosis in Aged Horse 101 Fig. 14—Exostosis of Carpus Resultant from Carpitis 102 Fig. 15—Distal End of Radius, Illustrating Effects of Carpitis 102 Fig. 16—Posterior View of Radius, Illustrating Effects of Splint 108 Fig. 17—Phalangeal Exosteses 120 Fig. 18—Rarefying Osteitis in Chronic Ringbone 121 Fig. 19—Phalangeal Exostoses in Chronic Ringbone 122 Fig. 20—Contraction of Superficial Digital Flexor Tendon Due to Tendinitis 138 Fig. 21—Contraction of Deep Flexor Tendon Due to Tendinitis 139 Fig. 22—Chronic Case of Contraction of Both Flexor Tendons of the Phalanges 140 Fig. 23—Contraction of Superficial and Deep Flexor Tendons 141 Fig. 24—Contraction of Superficial Digital Flexor and Slight Contraction of Deep Flexor Tendon 142 Fig. 25—"Fish Knees" 145 Fig. 26—Extreme Dorsal Flexion 146 Fig. 27—A Good Style of Shoe for Bracing the Fetlock 148 Fig. 28—The Roberts Brace in Operation 149 Fig. 29—Distension of Theca of Extensor of the Digit 151 Fig. 30—Rarefying Osteitis Wherein Articular Cartilage Was Destroyed 153 Fig. 31—Ringbone and Sidebone 156 Fig. 32—Position Assumed by Horse Having Unilateral Navicular Disease 159 Fig. 33—The Hoof in Chronic Laminitis 165 Fig. 34—Effects of Laminitis 166 Fig. 35—Cochran Shoe, Inferior Surface 168 Fig. 36—Cochran Shoe, Superior Surface 169 Fig. 37—Hyperplasia of Eight Forefoot Due to Chronic Quittor 176 Fig. 38—Chronic Quittor, Left Hind Foot 177 Fig. 39—Skiagraph of Foot 179 Fig. 40—Sagital Section of Eight Hock 186 Fig. 41—Muscles of Right Leg; Front View 187 Fig. 42—Muscles of Lower Part of Thigh, Leg and Foot 189 Fig. 43—Right Stifle Joint; Lateral View 190 Fig. 44—Left Stifle Joint; Medial View 191 Fig. 45—Left Stifle Joint; Front View 193 Fig. 46—Oblique Fracture of the Femur 200 Fig. 47—Fracture of Femur After Six Months' Treatment 201 Fig. 48—Aorta and Its Branches Showing Location of Thrombi 210 Fig. 49—Thrombosis of the Aorta, Iliacs and Branches 211 Fig. 50—Chronic Gonitis 218 Fig. 51—Position Assumed in Gonitis 219 Fig. 52—Spring-halt 226 Fig. 53—Lateral View of Tarsus Showing Effects of Tarsitis 228 Fig. 54—Right Hock Joint 231 Fig. 55—Spavin 235 Fig. 56—Bog Spavin 243 Fig. 57—Thoroughpin 247 Fig. 58—Fibrosity of Tarsus in Chronic Thoroughpin 248 Fig. 59—Another View of Case Shown in Fig. 58 249 Fig. 60—"Capped Hock" 252 Fig. 61—Chronic Lymphangitis 258 Fig. 62—Elephantiasis 259
Lameness is a symptom of an ailment or affection and is not to be considered in itself as an anomalous condition. It is the manifestation of a structural or functional disorder of some part of the locomotory apparatus, characterized by a limping or halting gait. Therefore, any affection causing a sensation and sign of pain which is increased by the bearing of weight upon the affected member, or by the moving of such a distressed part, results in an irregularity in locomotion, which is known as lameness or claudication. A halting gait may also be produced by the abnormal development of a member, or by the shortening of the leg occasioned by the loss of a shoe.
For descriptive purposes lameness may be classified as true and false. True lameness is such as is occasioned by structural or functional defects of some part of the apparatus of locomotion, such as would be caused by spavin, ring-bone, or tendinitis. False lameness is an impediment in the gait not caused by structural or functional disturbances, but is brought on by conditions such as may result from the too rapid driving of an unbridle-wise colt over an irregular road surface, or by urging a horse to trot at a pace exceeding the normal gait of the animal's capacity, causing it to "crow-hop" or to lose balance in the stride. The latter manifestation might, to the inexperienced eye, simulate true lameness of the hind legs, but in reality, is merely the result of the animal having been forced to assume an abnormal pace and a lack of balance in locomotion is the consequence.
The degree of lameness, though variable in different instances, is in most cases proportionate to the causative factor, and this fact serves as a helpful indicator in the matter of establishing a diagnosis and giving the prognosis, especially in cases of somewhat unusual character. An animal may be slightly lame and the exhibition of lameness be such as to render the cause bafflingly obscure. Cases of this nature are sometimes quite difficult to classify and in occasional instances a positive diagnosis is impossible. Subjects of this kind may not be sufficiently inconvenienced to warrant their being taken out of service, yet a lame horse, no matter how slightly affected, should not be continued in service unless it can be positively established that the degree of discomfort occasioned by the claudication is small and the work to be done by the animal, of the sort that will not aggravate the condition.
Subjects that are very lame—so lame that little weight is borne by the affected member—are, of course, unfit for service and as a rule are not difficult of diagnosis. For instance, a fracture of the second phalanx would cause much more lameness than an injury to the lateral ligament of the coronary joint wherein there had occurred only a slight sprain, and though crepitation is not recognized, the diagnostician is not justified in excluding the possibility of fracture, if the lameness seems disproportionate to the apparent first cause.
The course taken by cases of lameness is as variable as the degree of its manifestation, and no one can definitely predict the duration of any given cause of claudication.
Because of the fact that horses are not often good self-nurses at best, and that it is difficult to enforce proper care for the parts affected, one can not wisely state that resolution will promptly follow in an acute involvement, nor can he predict that the case will or will not become chronic. Experience has proved that complete or partial recovery may result, or again, that no change may occur in any given case, and that in some instances even where rational treatment is early administered, a decided aggravation of the condition may follow unaccountably.
However, because of the economic element to be reckoned with, it is of some value to be able to give a fairly accurate prognosis in the handling of cases of lameness, as in the majority of instances the treatment and manner of after-care are determined largely by the expense that any prescribed line of attention will occasion.
A case of acute bone spavin in a horse of little value is not generally treated in a manner that will incur an expense equivalent to one-half the value of the subject. The fact is always to be considered in such cases, that even where ideal conditions favor proper treatment, the outcome is uncertain. Where less than six weeks of rest can be allowed the animal, one affected with bone spavin would therefore not be treated with the expectation of obtaining good results, as six weeks' time, at least, is necessary for a successful outcome. If the cost attending the enforced idleness of an animal of this kind is considered prohibitive for the employment of proper measures to affect a cure, and if lameness is slight, the animal should be given suitable work, but in cases of articular spavin in aged subjects, they should be humanely destroyed and not subjected to prolonged misery.
A thorough knowledge of the structure and functions of the affected parts is necessary to proceed in cases of lameness; likewise, the age, conformation and temperament of the subject need to be taken into consideration; the presence or absence of complications demand the attention; the kind of care the subject will probably receive directly influences the outcome; and the character of service expected of the subject, too, needs to be carefully considered before the ultimate outcome may reasonably be foretold.
The practitioner is often confronted with the problem of how best to handle certain cases. Will they do better under conditions where absolute quiet is enforced, or is it preferable to allow exercise at will? The temperament of the animal must be considered in such cases, and if a lame horse is too active and playful when given his freedom, exercise must be restricted or prevented, as the case may require. In cases of strains of tendons, during the acute stage, immobilization of the affected parts is in order. In certain sub-acute inflammatory processes or in instances of paralytic disturbance where convalescence is in progress, moderate exercise is highly beneficial.
Consequently, each case in itself presents an individual problem to be judged and handled in the manner experience has taught to be most effective, appropriate and practical, and the veterinarian should give due consideration to the comfort and welfare of the crippled animal as well as to the interests of the owner.
ETIOLOGY AND OCCURRENCE.
In discussions of pathological conditions contributing to lameness in the horse, cause is generally classified under two heads—predisposing and exciting. It becomes necessary, however, to adopt a more general and comprehensive method of classification, herein, which will enable the reader to obtain a better conception of the subject and to more clearly associate the parts so grouped descriptively.
Though predisposing factors, such as faulty conformation, are often to be reckoned with, exciting causes predominate more frequently in any given number of cases. The noble tendency of the horse to serve its master under the stress of pain, even to the point of complete exhaustion and sudden death, should win for these willing servants a deeper consideration of their welfare. Too frequently are their manifestations of discomfort allowed to pass unheeded by careless, incompetent drivers lacking in a sense of compassion. Symptoms of malaise should never be ignored in any case; the humane and economic features should be realized by any owner of animals.
In the consideration of group causes, lameness may be said to originate from affections of bones, ligaments, thecae and bursae, muscles and tendons, nerves, lymph vessels and glands, and blood vessels, and may also result from an involvement of one or several of the aforementioned tissues, caused by rheumatism. Further, affections of the feet merit separate consideration, and, finally, a miscellaneous grouping of various dissimilar ailments, which for the most part, do not directly involve the locomotory apparatus but do, by their nature, impede normal movement.
AFFECTIONS OF BONES.
The bony column serving as the framework and support of the legs, probably constitutes the most vital element having to do with weight bearing and locomotion, and therefore during the acute and painful stage of bone affections, the pain becomes more intense in the process and pressure of standing than when the member is swung or advanced.
Certain bones are so well protected by muscular structures that they are not frequently injured except as a result of violence which may produce fracture. However, there are certain bones which receive the constant shock of concussion when the animal is subjected to daily, rapid work on hard road surfaces. Splints, ringbones and spavins are the most general examples produced by these conditions.
Varying pathological developments often result from concussion, contusion or other violent shocks to the bony structures. In such cases there either follows a simple periostitis which may resolve spontaneously with no obvious outward symptom, or osteitis, which may occur with tissue changes, as in exostosis; or the case may produce any degree of reaction between these two possible extremes.
Rarefying Osteitis, or Degenerative Changes.
Certain bone affections, such as osteomalacia or osteoporosis, are in the main, responsible for distortions and morphological changes of bone, causing lameness, permanent blemish and even resulting in death of the affected animal. The climatic conditions in some localities favor these occurrences but they may also be ascribed to improper food constituents and to possible infective agencies.
Rarefying degenerative changes manifested by exostosis involving the phalanges of the young, causing ringbone, are fairly common in occurrence throughout this country. This is due, supposedly, to a lack of mineral substance in the bony structure of the affected animals, and is known as rachitis—commonly called rickets. Since the affected subjects suffer involvement of several of the extremities at the same time, the theory of rachitic origin seems well supported.
Fractures of bones constitute serious conditions and are always manifested by lameness. A sub-classification is essential here for the student of veterinary medicine who would comprehend the technic of reduction and subsequent treatment in such cases.
Fractures are classified by many authorities as being simple, compound, and comminuted. This method is practical because it separates dissimilar conditions. There are also grouped fractures, the pathologic anatomy of which is similar. Classification on an etiological basis would attempt to associate conditions, the morbid anatomy and gravity of which would justly preclude their being combined.
Simple Fracture is a condition where the continuity of the bone has been broken without serious destruction of the soft structures adjacent, and where no opening has been made to the surface of the flesh. Such fractures do not reduce the bone to fragments. Long bones are frequently subjected to simple fracture, while short thick bones, such as the second phalanx, may suffer multiple or comminuted fractures.
Compound Fracture designates a break of bone with the destruction of the soft tissues covering it, making an open wound to the surface of the skin. This form of fracture is serious because of the attendant danger of infection, and in treatment, necessitates special precaution being taken in the application of splints that the wound may be cared for without infection of the tissues. These fractures generally occur as a result of some forceful impact through the flesh to the bone, or where the bones are driven outward by the blow. Common examples are in fractures of the metacarpus and metatarsus of the first phalanx. This kind of injury in mature horses usually produces an irreparable condition, and viewed economically, is generally considered fatal.
Comminuted Fractures, as the term implies, are those cases wherein the bone is reduced to a number of small pieces. This kind of break may be classified as simple-comminuted fracture when the skin is unbroken, and when the bone is exposed as a result of the injury, it is known as a compound-comminuted fracture. Such fractures are caused by violent contusion or where the member is caught between two objects and crushed.
Fractures are called multiple when the bone is reduced to a number of pieces of large size. This condition differs from a comminuted fracture in that the multiple fracture may break the bone into several pieces without the pieces being ground or crushed, and the affected bone may still retain its normal shape.
Further classification is of value in describing fractures of bone with respect to the manner in which the bone is broken—the direction of the fissure or fissures in relation to its long axis.
A fracture is transverse when the bone is broken at a right angle from its long axis. Such breaks when simple, are the least trouble to care for because there is little likelihood that the broken ends of bone will become so displaced that they will not remain in apposition. Simple transverse fracture of the metacarpus, for instance, constitutes a favorable case for treatment if other conditions are favorable.
Oblique fractures, as may be surmised, are solutions of continuity of bone in such manner that the fissure crosses the long axis of a bone at an acute or obtuse angle. These fractures are prone to injure the soft structures adjacent, and are frequently compound, as well. Moreover, because of the fact that the apposing pieces of bone are beveled, the broken ends of bone are likely to pass one another in such a way as to shorten the distance between the extremities of the injured member. Contraction of muscles also tends to exert traction upon a bone so fractured, resulting in a lateral approximation of the diaphysis and thus preventing union because the broken surfaces are not in proper contact.
Fractures are longitudinal when the fissure is parallel with the long axis of the bone. This variety of break is not infrequent in the first phalanx; and a vertical fracture of the second phalanx is also said to be longitudinal, however, there is little difference (if any, in some subjects) between the vertical and transverse diameters of this particular bone.
Green stick fractures are essentially those resulting from falls to young animals. They are usually sub-periosteal and when the periosteum is left intact or nearly so, no crepitation is discernible. If this fracture is simple, prompt recovery may be expected. Bones of young animals, because they do not contain proportionately as much mineral substance as do bones of adults, are more resilient and less apt to become completely fractured. They are, however, subject to what is known as green stick fracture.
Impacted fractures are usually occasioned by falls. When the weight of the body is suddenly caught by a member in such manner as to forcefully drive the epiphyseal portions of bone into and against the diaphysis, multiple longitudinal fractures occur at the point of least resistance. Parts so affected undergo a fibrillary separation, increasing the transverse diameter of the bone; or if the impact has been sufficiently violent, the portion becomes an amorphous mass.
In a treatise on the subject of lameness, the bones chiefly concerned and most often affected must be especially considered. The shape and size of a bone when injured, determines in a measure, the course and probable outcome in most cases, but of first and greater importance is the function of the bone. A fracture of the fibula in the horse need not incapacitate the subject, but a tibial fracture is serious and generally proves cause for fatal termination. The body of the scapula may be completely fractured and recovery will probably result in most cases without much attention being given to the subject, yet a fracture of the neck of this same bone constitutes an injury of serious consequence. The difference in the function of different parts of this same bone, as well as its shape and mode of attachment, determine the gravity of the case; so it is in fractures of other bones with respect to the course and prognosis of the case—function is the important factor to be considered.
Next in importance is the age of the animal suffering fracture of the bone. Capacity for regeneration is naturally greater in a vigorous, young animal than in aged or even middle-aged subjects. A healthy condition of the bone and the body favor the process of repair in case of fracture, and prognosis may be favorable or unfavorable, depending upon these factors mentioned for consideration. Individuals of the same species, differing in temperament, may comport themselves in a manner that is conductive to prompt recovery, or to early destruction. This feature cannot be overestimated in importance, as it is sometimes a decisive element, regardless of other conditions. A horse suffering from an otherwise remediable pelvic fracture may be so worried and tortured by being confined in a sling that the case calls for special attention and care because of the animal's temperament. Sometimes, the constant presence of a kind attendant will so reassure the subject that it will become resigned to unnatural confinement, in a day or two. This precaution may, in itself, determine the outcome, and the wise veterinarian will not overlook this feature or fail to deviate from the usual rote in the handling of average cases. Recovery may be brought about in irritable subjects by this concession to the individual idiosyncrasies of such animals.
AFFECTIONS OF LIGAMENTS.
Ligaments which have to do with the locomotory apparatus are, for the most part, inelastic structures which are composed of white fibrous tissue and serve to join together the articular ends of bones; to bind down tendons; and to act as sheathes or grooves through which tendons pass, and as capsular membranes for retention of synovia in contact with articular surfaces of bones.
Ligaments are injured less frequently than are bones. Because of their flexibility they escape fracture in the manner that bones suffer. They are, however, completely severed by being cut or ruptured, though fibrillary fracture the result of constant or intermittent tensile strain is of more frequent occurrence.
Simple inflammation of ligaments is of occasional occurrence but, unless considerable injury is done this tissue, no perceptible manifestation of injury results. No doubt many cases wherein fibrillary fracture of ligaments (sprain) takes place some lameness is caused, but because of the dense, comparatively nonvascular nature of these structures, little if any manifestation, except lameness, is evident. And such cases, if recognized are usually diagnosed by excluding the existence of other possible causes and conditions which might also cause lameness.
Certain ligaments are subjected to strain more than are others and therefore, when so involved, frequently cause lameness. Examples of this kind are affections of the collateral (lateral) ligaments of the phalanges. Because of the leverage afforded by the transverse diameter of the foot, when an animal is made to travel over uneven road surfaces, considerable strain is brought to bear on the collateral ligaments of the phalanges. A sequel to this form of injury is a circumscribed periostitis at the site of attachment of the ligaments and frequently the formation of an exostosis—ringbone—results.
Where sudden and violent strain is placed upon a ligament and rupture occurs, the division is usually effected by the ligament being torn from its attachment to the bone. In such cases, a portion of periosteum and bone is usually detached and the condition may then properly be called one of fracture. In some cases of this kind recovery is tardy, because of the difficulty in maintaining perfect apposition of the divided structures, and reactionary inflammation is not of sufficient extent to enhance prompt repair. In fact, some cases of this kind seem to progress more favorably, when no attempt at immobilization of the affected member is attempted.
If some freedom of movement is allowed, acute inflammation resulting in nature's provisional swelling soon develops and repair is hastened because of increased vascularity. But where luxation of phalanges accompanies sprain, reposition and immobilization are necessary—that is if cases are thought likely to benefit by any treatment.
Luxation or dislocation is a condition where the normal relation between articular ends of bones has been deranged to the extent that partial or complete loss of function results. When a bone is luxated (out of joint), there has occurred a partial or complete rupture of certain ligaments or tendons; or a bone may be luxated when an abnormal or unusual elasticity of inhibitory ligaments or tendons obtains.
Luxations may be practically classified as temporary and fixed. In temporary luxations, disarticulation is but momentary and spontaneous reposition always results; while a fixed luxation does not reduce spontaneously but remains luxated until reposition is effected by proper manipulation and treatment. Fixed luxation may be of such character as to be practically irreducible because of extensive damage done to ligaments or cartilage. Where a complete luxation of the metacarpophalangeal joint exists, it is probable that in most cases sufficient injury to collateral and capsular ligaments has been done to render complete recovery improbable, if not impossible.
Temporary luxation of the patella is a common affection of the horse and fixed luxation of this bone also occurs. As a matter of fact, in the horse, patellar luxation is the one frequent affection of this kind.
As a rule, complete disarticulation immobilizes the affected joint and in most instances there is noticeable an abnormal prominence in the immediate vicinity—in patellar luxation, the whole bone. In other instances the articular portion only, of the affected bone is malpositioned. Usually, luxation and fracture may be differentiated in that there is no crepitation in luxation and more or less crepitation exists in fracture.
It is evident, when one considers the symptomatology and nature of the affection, that fixed luxation is usually caused by undue strain or violent and abnormal movement of a part. Joints having the greater freedom of movement are apt to suffer luxation more frequently.
The study of arthritis in the horse is limited to a consideration of joint inflammations which, for the most part, are of traumatic origin. Unlike the human, the horse is not subject to many forms of specific arthritis—tubercular, gonorrheal, syphilitic, etc.
A practical manner of classification of arthritis is traumatic and metastatic.
Traumatic arthritis may result from all sorts of accidents wherein joints are contused. Such cases may be considered as being caused by direct injuries. Instances of this kind, depending on the degree of insult, manifest evidence of injury which ranges from a simple synovitis to the most active inflammatory involvement of the entire structure and adjacent tissues.
The reactionary inflammation which attends a case of tarsitis caused by a horse being kicked is a good example of the result of direct injury. Such cases, if the contusion is of sufficient violence, result in arthritis and periarthritis. In inactive farm horses, during cold weather, this condition becomes chronic, swelling remains for weeks after all lameness and pain have subsided and occasionally hyperthrophy is permanent.
Arthritis occasioned by indirect injury, such as characterizes joint inflammation from continuous concussion, is seen in horses that are worked at a rapid pace on city streets or other hard road surfaces. Such affections may be acute, as in some cases of spavin, but are usually inflammatory conditions that do not occasion serious disturbance when these affections become chronic. If the involvement persists with sufficient active inflammation, there may follow erosion of cartilage and incurable lameness. If extensive necrosis of cartilage takes place, the attendant pain will be sufficient to cause the animal to favor the diseased part and such immobilization enhances early ankylosis—nature's substitute for resolution in this disease.
Wounds invading the tissues adjacent to joints, when these wounds are of considerable extent, cause inflammation of such articulations by contiguous extension of inflammation. As long as an injury remains practically aseptic, or if infected and the septic process does not involve the joint proper by direct extension, no more serious disturbance than a simple synovitis will result. If, instead, a periarthritic inflammation is serious or destructive in character, the type of arthritis will be grave—even though due to an indirect cause.
Where a vulnerant body penetrates all structures and invades the interior of the joint capsule the result is that a more or less active disturbance is incited. The introduction of a sterile instrument into a joint cavity, under strict asepsis, where a perfect technic is executed, does not cause perceptible manifestation of the injury, if the opening so made is small—such as a suitable exploratory trocar makes. But a puncture made in a similar manner and with the same instrument without due regard to asepsis is likely to cause an infectious synovitis and arthritis usually follows.
A larger opening than is produced by means of an exploratory trochar may be made into a joint cavity, causing escape of synovia as it is secreted for days and even for weeks and no serious or permanent trouble is experienced in some cases. If the synovitis or arthritis remains non-infected and the wound, traumatic or surgical, is not too large, healing by granulation occurs, and the discharge of synovia ceases. However, if synovial discharge persists too long because of tardy closure of an open joint, there is great danger of infection gaining entrance into the synovial cavity, or in some instances, desiccation of endothelial cells of the articulation occurs, in areas, and the reactionary inflammation eventually results in ankylosis.
A small puncture which introduces into the synovial cavity infectious material of active virulence will cause an arthritis that is more serious, much more painful and more difficult to handle than is occasioned by a wound of moderate size, that affords ready escape of synovia even through the virulence of the infection be the same.
Synovia is a good culture medium and the environment is ideal for multiplication of bacteria; consequently, the grave disturbances which may attend the introduction of pathogenic organisms into a synovial cavity as the result of a puncture wound are not to be forgotten. The veterinarian is in no position to estimate the virulency of organisms so introduced; neither can he determine the exact degree of resistance possessed by the subject in any given case. Therefore, he is uncertain as to the best method of handling such cases where an injury has been recently inflicted and positive evidence of the existence of an infectious synovitis is not present. If one could determine in advance the degree of infection and injury that is to follow small penetrant wounds of joint capsules, it would then be possible to select certain cases and immediately drain away all synovia and fill the cavity by injection with suitable antiseptic solutions.
This offers a broad field for experimentation which will in time be productive of a radical change in the manner of treating such cases.
Metastatic arthritis is seen more frequently in colts or young animals than in mature horses and we here take the liberty of classifying with the arthritis of omphalophlebitis and strangles the so-called rheumatic variety.
A specific polyarthritis or synovitis which attends navel infection of foals is perhaps the most frequent form of arthritis that is to be considered metastatic. This condition is truly a disease of young animals and, while it is a specific arthritis, the cause is yet to be attributed to any definite pathogenic organism with certainty. This condition is well defined by Bollinger as quoted by Hoare, when he calls it a purulent omphalophlebitis due to local infection of the umbilicus and umbilical vessels, by pyogenic organisms, causing a metastatic pyemia.
This affection is grave; its course is comparatively brief; the prognosis is usually unfavorable; and omphalophlebitis occasions a form of lameness which at once impresses the practitioner that serious constitutional disturbance exists. Its consideration properly belongs to discussions on practice or obstetrics and diseases of the new born, and it has received careful attention and is discussed at length in these works.
A second form of metastatic arthritis is met with in strangles. Strangles occurs in the young principally and is not a frequent cause of synovitis or arthritis in the adult animal.
Strangles or distemper is, according to most pathologists, due to the Streptococcus equi. Hoare states that in this type of specific arthritis the contagium is probably carried by the blood. He gives it as his opinion that even laminitis has occurred as a result of the streptococcus-equi. This, indeed, would point toward probable extension by the blood as well as by way of lymph vessels.
Septic synovitis and infectious arthritis are always serious affections even in young animals and much depends upon individual resistance and early rational treatment in such cases, if recovery is to follow.
The same general plan of treatment is indicated in this kind of septic synovitis as is employed in all cases of infective synovitis and septic infection in open joints. There is to be considered, however, the fact that the young animal is more agile, a better self-nurse, and in a general way more apt to recover than is the adult, under similar conditions.
Rheumatic arthritis, if one is justified in classifying rheumatic inflammation of joints as a metastatic form of arthritis, is not a common condition, though seen in mature and aged animals. Cases that may be diagnosed with certainty are usually advanced affections wherein dependable history is obtainable and the symptoms are well marked.
Rheumatism may be thought of, with respect to arthritic inflammation caused thereby, as a sort of pyemia. Undoubtedly, exposure to wet and cold weather is an active factor, but probably a predisposing one only. Likewise a member that suffers from chronic inflammation due to recurrent injury or to constant or repeated strain is less able to resist the vicissitudes of climate and work.
Consequently, rheumatic arthritis is to be seen affecting horses that are in service, more often at heavy draft work where they are exposed to severe straining of joints; where stabling is insanitary; and where they are obliged to lie down (if they do not remain standing) upon cold and wet ground or upon hard unbedded floors or paving.
Where such inhumane and cruel treatment is given animals those responsible ought to be impressed with the unfairness to the animal as well as the economic loss occasioned by inflicting such unnecessary and merciless treatment upon their helpless and uncomplaining subjects. The very nature of the veterinarian's work affords him constant and frequent opportunity to convince those who are responsible for keeping animals in this manner, that it is inhumane and unprofitable.
Cases of this kind are not uncommon about some grading and lumbering camps and in contract work where, often, shelter for animals is given little thought; the result is a cruel waste of horseflesh.
Chronic articular rheumatism is occasionally observed in young animals that have never been in service. In these cases it seems that there exists an individual susceptibility and in some instances the condition is recurrent. Each attack is of longer duration, and eventually death results from continued suffering, emaciation and intoxication.
AFFECTIONS OF BURSAE AND THECAE.
Acute bursitis and thecitis is of frequent occurrence in horses because of direct injury from contusion, punctures and other forms of traumatism. These synovial membranes, with few exceptions, when inflamed occasion a synovitis that may be very acute, yet there is less manifestation of pain than in arthritis.
It is only in structures such as the bursa intertubercularis or in the sheath of the deep digital flexor that an inflammation causes much pain and is apt to result in permanent lameness. This is due to the peculiar character of the function of such structures.
An acute inflammation of a small bursa may even result in the destruction of such synovial apparatus without serious inconvenience to the subject, either at the time of destruction or thereafter. Obliteration of the superficial bursa over the summit of the os calcis is not likely to cause serious inconvenience or distress to the subject unless it be due to an infected wound. Even then, with reasonably good care given the animal, recovery is almost certain. Complete return of function of the member and cessation of lameness takes place within a few weeks in the average case.
Where an infectious synovitis involves a structure such as the sheath of the tendon of the deep digital flexor (perforans) the condition is grave and because of the location of this theca the prognosis is not much more favorable than in an articular synovitis.
Inflammation of bursae and thecae may be classified on a chronological basis with propriety because the duration of such affections, in many cases, materially modifies the result. A chronic inflammatory involvement of a theca through which an important tendon plays may cause adhesions to form. Or there may occur erosions of the parts with eventual hypertrophy and loss of function, partial or complete.
However, in general practice a classification on an etiological basis is probably more practical and we shall consider inflammation of bursae and thecae as infectious and noninfectious.
Infectious bursitis and thecitis is usually the result of direct introduction of septic material into the synovial structure by means of injuries. Infection by contiguous extension occurs and also metastatic involvement is met with occasionally.
The noninfectious inflammation of bursae and thecae usually result from contusions or strains and generally run their course without becoming infective in character, where vitality and resistance of the subject are normal.
In a general way, inflammation and other affections of bursae and thecae are considered very similar to like affections of joints.
AFFECTIONS OF MUSCLES AND TENDONS.
Muscles and tendons having to do with locomotion are more frequently injured than are any of the other structures whose function is to propel the body or sustain weight. This is due in part to the exposed position of muscles and tendons. They serve as a protection to the underlying structures and in this manner receive many blows the force and violence of which are spent before injury extends beyond these tissues.
Muscles of the breast, shoulder and rump are most frequently the recipient of injuries of various kinds. The abductors of the thigh are subjected to bruising when horses are thrown astride of wagon poles or similar objects. Thus in one way or another muscle injuries are occasioned and cause lameness.
Traumatic affection of muscles of locomotion may be surface or subsurface—subsurface with little injury done the skin and fascia, but with subsurface extravasation of blood and masceration of tissue. Puncture wounds wherein the vulnerant body is of small diameter, are observed, and they occasion deep seated infectious inflammation of the parts affected, with surface wounds that are often unnoticeable. Such injuries—puncture wounds—are always serious, and because of the fact that, there exists little evidence of injury at the time of their infliction, treatment is usually deferred several days and often infection has become quite extensive when the practitioner is consulted.
Where infective wounds of muscles of locomotion occur, the course and gravity of the affection are directly influenced by the proximity of the injury to lymph plexuses. For instance, injuries causing an infectious inflammatory involvement of the adductors of the thigh may result in a generalization of the infection by way of the inguinal lymph glands.
Large open wounds that extend deep into muscles, render inactive such structures, and even where division is not complete, the pain occasioned causes the subject to favor the part in every way possible. Contraction of muscular fibers of such parts increases pain and because of this fact groups of muscles are at times disabled because of injury done to one muscle. Instances of this kind are frequently seen where shoulder injuries, which affect but one muscle, exist; yet because of such injury a marked swinging-leg lameness is present.
Tendons, because of their inelasticity, are subjected to injuries peculiar to themselves. In addition to being affected as are muscles, wounds of many kinds are found to affect tendons—contusions, interference wounds, penetrant wounds, incised wounds and lacerations.
However, the commoner form of injury done tendons, is strain or sprain. Because of the sudden tensile strain brought to bear upon tendons in the shocks of concussion, as well as in propulsion of the body, there frequently occurs a rupture of fibers and this we know as sprain.
Sprains may be considered as fibrillary fractures of soft structures and since this form of injury is subsurface, and limited to fractional portions of tendons, the inflammation occasioned usually remains an aseptic one. Reaction to this form of injury is characterized by inflammation, the course of which is erratic and variable. In chronic inflammation of tendons, where animals are continued in service, the usual sequel is contraction, or shortening of these structures.
The degree of contraction as well as its import varies in different subjects and in the various tendons which may be affected. Contraction is a slow-going process that is progressive, gradually causing a decrease in the length of the affected structure and eventually rendering the animal useless.
The practice of applying shoes with extended toe-calks for the purpose of "stretching" contracted deep digital flexor tendons (flexor pedis perforans) cannot be too strongly condemned. While the addition of an extension such as is ordinarily employed to the toe of a shoe of this kind, prevents for a time, frequent stumbling in such cases, the increased tensile strain which is thus occasioned hastens further contraction and subjects animals so shod to much unnecessary pain.
AFFECTIONS OF NERVES.
Because of their being protected by other structures, nerve trunks, which supply muscles of locomotion, are not subjected to frequent injuries such as contusions. However, they do become injured at times and the result is lameness, more or less severe.
Lameness originating from nerve affection, may involve central structures as, for example, the spinal cord, medulla oblongata or parts of the brain. In making an examination of some lame animals it is necessary to distinguish between cases of lameness that are of central origin and marked by incooerdination of movement, and disturbances caused by other affections. Tetanus in its incipiency should not be confused with laminitis involving all four feet, or with certain forms of pleuritis, when careful examination is made, yet, in a way, to one not trained, the clinical symptoms are similar.
Disturbances of nerve function are caused in a variety of ways. It is not within the scope of this work to discuss central nervous disturbances caused by ingestion of mouldy provender, or disturbances of the brain or cord occasioned by infectious diseases, but mention of the existence of such conditions is appropriate.
By direct injury the result of blows, certain nerves are injured and muscles supplied by such nerves are rendered inactive. Depending upon the nature and extent of an injury thus inflicted, so the manner in which the affection is manifested varies. The suprascapular nerve is rather frequently injured causing partial or complete loss of function of the structures supplied by this nerve, and abduction of the scapulohumeral joint naturally results.
In some cases of dystocia the obturator nerve, (or nerves, if the involvement is bilateral), becomes injured by being caught between the maternal pelvis and some dense part of the fetus. This results in paralysis of the adductors of the thigh if sufficient injury is done.
It is said that nerves become over-stretched and held tense, in certain positions in which animals are obliged to remain while cast in confinement such as in some instances where unusual methods of restraint are employed. When the fore feet are drawn backward in such manner that great strain is put upon the radial nerve, it suffers more or less injury, and this is followed by partial or complete paralysis which may be temporary or permanent.
Degenerative changes affecting nerves, as in other tissues, occur and more or less locomotory impediment will follow—this depending upon the nerve or nerves affected and the nature of such involvement. Tumors may surround nerves and eventually the nerve so exposed becomes implicated in the destructive process. Before degenerative changes take place in the nerve substance, in such cases, pressure may completely paralyze a nerve when it is so situated. Melanotic tumors in the paraproctal tissue in some cases, because of the large size of the new-growths, cause paralysis of the sciatic nerve. The author has seen one case of brachial paralysis occasioned by an enormous development of fibrous tissue involving the structures about the ulna.
AFFECTIONS OF BLOOD VESSELS.
Lameness caused by disturbances of circulation may be due to structural affection of vessels, or functional disorders of the heart, and in some instances, a combination of these causes may be active.
Direct involvement of vessels is the commoner form of circulatory disturbance which occasions lameness, and the most frequent cause is of parasitic origin. Sclerostomiasis with attendant arteritis, thrombus formation and subsequent lodgement of emboli in the iliac, femoral, or other arteries, causes sufficient obstruction to prevent free circulation of blood, and the characteristic lameness of thrombosis results.
Indirect injury to vessels may occur because of contused wounds and subsequent inflammation of tissues supplied by such vessels. If the injury be of sufficient extent, considerable extravasation of blood will take place and the painfully swollen parts necessarily impair locomotion. In such instances lymph vessels participate in the disturbance, and the condition then becomes one wherein lymphangitis is the predominant disturbing element.
Angiomatous tumors are occasionally found affecting horses' legs—usually the result of some injury; and because of their size or position, they mechanically interfere with function. Furthermore, when such tumors are located on the inner or flexor side of joints, enough pain is occasioned that affected animals show evidence of distress, usually by intermittent lameness.
Horses do not suffer from distension of veins as does man, that is, there is rarely to be seen a case wherein much disturbance from this source exists.
AFFECTIONS OF LYMPH VESSELS AND GLANDS.
Inflamed lymph vessels and glands, the result of various causes, is a rather common source of lameness of horses. When one considers the proportion of tissue that is composed of lymph vessels and glands, it is then obvious that inflammation of these structures should cause a painful affection of members, when so affected, and that marked lameness and, in some instances, general constitutional disturbance such as anorexia, hyperthermia and general circulatory disorder are to follow.
Lymphangitis is most frequently occasioned by the introduction of septic material into the tissues; consequently, infectious lymphangitis is more frequently observed than the non-infectious type.
Specific infectious forms of lymphangitis are seen in glanders and in strangles; infectious types of this disturbance are found in many instances where, initially, a localized or circumscribed infection has occurred—the contagium having been introduced by way of an injury. An example of this kind is to be seen in a wound perforating the tibial fascia, where the injury is inflicted by means of a horse being kicked by another animal shod with sharp shoe-calks. Cases of this kind invariably result in a septic lymphangitis, and frequently lymphadenitis also occurs, for the inguinal lymph glands are so situated that their becoming contaminated is almost certain.
The trite phrase that "the tissues are bathed in lymph" should make clear the reason for the frequent occurrence of infectious lymphangitis and lymphadenitis. Foreign substances, bacteria and their products, inorganic material and in fact, anything that is introduced into the tissues, if soluble or miscible, will be taken up and conveyed by the afferent lymph vessels and disseminated throughout the system—hence the constitutional disturbances so frequently thus caused.
A non-infectious type of lymphangitis is frequently seen in the heavy draft breeds of horses and in such cases one or both hind legs are involved—it is very seldom that the thoracic limbs become so affected. Law refers to this ailment as "Acute Lymphangitis of Plethora in Horse." When one takes into consideration that these cases so frequently occur in heavy draft animals that are not worked regularly, that the pelvic limbs are the ones involved, and that the disorder often runs a short course (recovery often taking place within two or three days, with no treatment given other than a purge, circulatory stimulants and walking exercise) it is plausible to ascribe the condition to idiopathic factors.
Admitting the frequency of non-infectious lymphangitis, the practitioner must not confuse this type with similar lymphatic inflammation occasioned by nail punctures of the foot. It is very embarrassing indeed to make a diagnosis of lymphangitis—expecting that the disturbance will terminate favorably and uneventually—and later to discover a sub-solar abscess caused by a nail prick in the region of the heel.
Recurrent attacks of this disturbance cause hypertrophy of the lymph vessels and in some cases lymphangiectasis. In old subjects used for dissection or surgical purposes, it is very evident that in the ones which have suffered from chronic lymphangitis there exists an excessive amount of sub-facial connective tissue, making subcutaneous neurectomies quite difficult in some instances.
A sequel of chronic lymphangitis is a condition known as elephantiasis. In such cases there occurs a hyperplasia of the skin and subcutaneous tissues, resulting in some instances, in the affected member attaining an enormous size. Sporadic cases of this kind are to be seen occasionally, and are apparently caused by repeated attacks of lymphangitis. The affection is not benefited by treatment, and while a horse's leg may become so heavy and cumbersome as to mechanically impede its gait, as well as to fatigue the subject when made to do service even at a slow pace, elephantiasis causes no constitutional derangement. The hind legs, in elephantiasis, are affected and a unilateral involvement is more often seen than a bilateral one. The legs may be enlarged from the extremity to the body, but ordinarily the affection does not extend higher than the hock or the mid-tibial region.
A chronic, progressive, hyperplastic-degeneration exists in some cases and the subjects are in time rendered unserviceable because of the burden of getting about encumbered by the affected extremity. In other animals hyperplasia progresses for a time—until the parts become greatly enlarged and conditions apparently attain an immutable state. Nevertheless animals so affected may continue in service for years without being distressed.
AFFECTIONS OF THE FEET.
Lameness is very often due to affections of the feet, and in all foot diseases probably the most constant cause is injury inflicted in some manner. Resultant from injury, there frequently develops complications and the one most often seen is infection.
Because of the fact that the feet are constantly exposed to germ-laden soil and filth, if not actually bathed in such infectious materials, it naturally follows that septic infection of some part of the feet must be of frequent occurrence.
Subsequent to being obliged to stand in mud and other damp or wet media, exposure to desiccating influences such as stabling upon dry floors, or at service on hot and dry road surfaces causes the insensitive parts of the feet to become dry, hard and brittle. This favors "checking" of the protecting structures and it frequently results in the formation of large fissures which expose the underlying sensitive parts of the feet and lameness is the inevitable outcome.
The function of the feet—bearing the weight of the animal at all times when the subject is not recumbent, and in addition to this, the increased strain put upon them at heavy draft work, together with the concussion and buffeting occasioned by locomotion, make the feet susceptible to frequent affections of various kinds.
Being almost completely encased by a somewhat inexpansible and insensitive wall and sole, renders the foot subject to pathologic changes peculiar to itself. The very nature of the structure of the foot together with the function of the sensitive lamina is sufficient cause for an affection unlike that seen involving other tissues—laminitis.
An exhaustive consideration of foot affections is a study in itself and one that comes within the realm of pathologic shoeing; nevertheless, a practical knowledge of diseases of the foot is indispensable in the diagnosis of lameness wherein the foot may be at fault.
The peculiar nature of foot affections renders them difficult of classification on any sort of basis that is helpful in the consideration of this subject. Injuries are the most constant cause of foot lameness, yet one must admit that there results complications because of infection in most instances; and that in some cases the injury is slight—just enough to permit the introduction of vulnerant organisms into the tissues. Therefore, one might well classify affections of the feet as infectious and non-infectious. There can be grouped in the class of infectious affections such conditions as nail pricks, calk wounds and canker. In the class of non-infectious affections one may consider conditions such as laminitis, strain and fractures.
[Footnote 1: A System of Veterinary Medicine by E. Wallis Hoare, F.R.C.V.S., Vol. I, page 519.]
[Footnote 2: Ibid, page 807.]
[Footnote 3: Vol. I, page 534, Veterinary Medicine, by James Law, F.R.C.V.S.]
To observe attentively is to remember distinctly.—Poe.
Before treatment is administered in constitutional disturbances resulting in disease, cause is logically sought; so, in order to handle effectively any case of lameness, it is necessary first to discover the source of the trouble and contributing conditions affecting the structures. Hence, diagnostic ability is the prime requisite; and a thorough knowledge of pathologic anatomy or of surgical technic is of little value if this knowledge is not applied with the insight of the trained diagnostician.
The cruel and unnecessary methods employed by those untrained for diagnostics, cannot be too vigorously condemned. For instance, the application of an active and depilating vesicant upon a large area on the gluteal or crural region, in a case where the practitioner "guesses" the condition to be one of "hip lameness," constitutes an exposition of gross ignorance, and at once stamps the perpetrator as a crude bungler without scientific insight whose works are no credit to his profession. How much better it would be, if the practitioner does not see fit to call in a competent consultant, to prescribe a suitable agent to be given internally, and to recommend complete rest for the subject.
In establishing a diagnosis in such cases, the student or practitioner seldom has recourse to laboratory assistance, and his work is done by means of physical examination; therefore, a thorough knowledge and a clear conception of the physiology of locomotion are essential. Memorizing nosological facts without an understanding of underlying principles is of no more practical benefit for qualification as a diagnostician in cases of lameness, than is the employment of similar methods in the study of theory and practice. A knowledge of the dosage of drugs does not in itself qualify one as being competent to administer such therapeutic agents to a proper effect. How much is a practitioner benefited by the knowledge that a high temperature is usually present in septic intoxication, if he is not possessed of a scientific understanding of anatomy, physiology, bacteriology and pathology, as well as the principles of clinical diagnosis?
In order to determine the reasons for certain symptoms manifested by the subject, an analysis of these symptoms is the proper method of procedure, insofar as this is possible. If one may reason that an animal assumes a certain position while at rest to allow relaxation of an inflamed tendon or ligament, such a fact enables the diagnostician to recall that this is indicative of some specific ailment. In acute tendinitis, the subject while at rest, maintains the affected member in volar flexion because this position permits relaxation of the inhibitory apparatus, including the inflamed tendon. Likewise, the various abnormal positions assumed,—adduction, abduction, undue flexion or pointing—have their own significance and are taken into account by the trained diagnostician in the course of an examination.
In the examination of lame subjects, where the cause is not obvious, a systematic method of diagnosis is pursued even by the most expert practitioners. In all obscure cases of lameness a methodical and thoroughly practical examination of the animal according to an established procedure is necessary to determine the nature and source of the affliction.
The first thing to be given consideration in diagnosis is the fact that related history of the case is not always dependable, because of lack of accurate observation or wilful deceit on the part of the owner or attendant. The successful veterinarian soon acquires the faculty of obtaining information in a manner best adapted to his client,—either by direct interrogation or by subtle means of suggestion, and in this way he draws out evaded facts essential to his diagnosis. In time he learns to make allowance for misstatements made to shield the owner or driver and to hide the facts of apparent neglect or abuse that the subject may have experienced. A suppurating cartilaginous quittor, complicated by the presence of a large amount of hyperplastic tissue, cannot be successfully represented to be an acute and recently developed affection, where a trained practitioner is left to judge the validity of the statement.
In complicated conditions, where there is evident a chronic disturbance which could not be conceived as sufficient cause for a marked manifestation of lameness, accurate history of the case may be of great aid in arriving at a diagnosis. An aged animal, having recently become very lame, showing a small exostosis on the first phalanx, and with the history given that the osseous deposit was of long standing, should at once lead the veterinarian to seek the source of trouble elsewhere.
As in all diagnostic work, a careful visual examination of the subject should be made before it is approached. The novice is given to hasty examination by palpation, not realizing how much may be revealed by a careful scrutiny of the subject. In this way he is led to erroneous conclusions which the skilled diagnostician has learned from experience to avoid. Too much emphasis cannot be placed on the importance of making a thoughtful visual examination in every instance before the subject is approached. In this examination, type, conformation and temperament are taken into account at once, for each of these qualities is in itself, a determining factor in predisposing a subject to certain ailments or inherent attributes, which may exert a favorable or unfavorable influence upon existing conditions and thus make recovery probable or otherwise.
Draft animals are less likely to be permanently incapacitated as a result of tendinitis, than are thoroughbreds. Likewise, one would not expect to find this affection present in heavy harness horses as frequently as in light harness animals.
Mal-formation of a part, or an asymmetrical development of the body as a whole, may render an animal susceptible to certain affections which cause lameness. A "tied in" hock predisposes the subject to curb, and an animal having powerful and well-developed hips and imperfectly formed hocks, will, if subjected to heavy work, be a favorable subject for bone spavin.
The matter of temperament cannot be disregarded in diagnosis, for in some instances, it is the chief determining factor which materially influences the outcome of the case. A nervous, excitable animal, that is kept at hard work, may, under some conditions, be expected to experience disturbances which more lethargic subjects escape. Nervous subjects, it is known, are more prone to azoturia than are those of lymphatic temperament. Furthermore, the lymphatic subject often recovers from certain bone fractures which are successfully treated only when the animal is sufficiently resigned by nature to remain confined in a sling for weeks without resistance.
The physiognomy of a subject is often indicative of the gravity of its condition. The facial expression of an animal suffering the throes of tetanus, azoturia, or acute synovitis, is readily recognized by the experienced eye, and upon physiognomy alone, in many instances, may the opinions regarding prognosis be based. Particularly is this true where death is a matter of minutes, or at most is only a few hours distant.
Due allowance should be made for restiveness manifested by some more nervous animals when the surroundings are strange and unusual. In such instances, even pathognomic symptoms may be masked to the extent that little, if any, sign of pain or malaise is evinced. In these cases the subject should be given sufficient time to adjust itself to the new environment, or it should be removed to a more suitable place for examination. Animals quickly detect the note of friendly reassurance in the human voice and can very often be calmed by being spoken to.
By visual examination one may detect the presence of various swellings or enlargements, such as characterize bruises and strains of tendons where inflammation is acute. Inflammation of the plantar (calcaneocuboid) ligament in curb is readily detected when the affected member is viewed in profile. Spavin, ringbone, splints, quittor and many other anomalous conditions may all be observed from certain proper angles.
The fact that the skins of most animals are pigmented and covered with hair, precludes the easy detection of erythema by visual examination, consequently this indicator of possible inflammation is not often made use of in the examination of equine subjects.
Attitude of the Subject.
The position assumed while the subject is in repose, is often characteristic of certain affections and this, of course, is noted at once. The manner in which the weight is borne by the animal at rest, should attract the attention of the diagnostician and if the attitude of the subject is abnormal or peculiar, the examiner tries to determine the reason for it. If weight-bearing causes symptoms of pain, the affected member will invariably be favored and held in some one of a number of positions. The foot may contact the ground squarely and yet the leg may remain relaxed and free from pressure; volar flexion, in such cases, is indicative of inflammation of a part of the flexor apparatus. If the condition be very painful, position of the afflicted member is frequently shifted, but in all cases where the pain is not so keenly felt, the inflamed member is held in a state of relaxation. There is need then, for a knowledge of anatomy and certain principles in physics to enable the observer to determine just which structures are purposely eased in this manner. Where palpation of parts is possible, one does not need to depend on visual examination alone, and it is always wise to take into consideration every factor that may influence conditions. Manipulation or palpation of the structures thought to be involved, should not be resorted to until a careful and thorough observation of the subject has revealed all that it can reveal to the diagnostician.
In all conditions where extreme pain is manifested by the constant desire of the animal to keep its foot in motion off the ground, examination should be made for local cause. This is seen in certain septic inflammations of the feet such as those caused by nail punctures invading the navicular joint, or in newly made wounds where nerves have been divided and the proximal end of such a nerve is exposed to pressure or irritation.
"Pointing" affords a comfortable position in some cases of navicular disease, and in a unilateral affection, one may observe the subject bearing weight with one sound member, while the affected foot is planted well ahead of the sound one. In a bilateral involvement of this kind, weight may be frequently shifted from one foot to the other, or in chronic cases, where no marked pain is experienced, the subject stands squarely upon both front feet and no peculiar shifting of weight or pointing is evident.
In some cases of hip or shoulder involvement, complete relaxation of all parts of the affected member may be noticed. In brachial paralysis, the pectoral member is held limply; if the patient is made to move, it is evident there is lack of innervation to the afflicted part. In some cases where contusion has caused acute inflammation of the member, the subject instinctively tries to keep it inactive to relieve the pain which movement occasions.
Where there is an active and painful inflammation of the prescapular lymph glands and contiguous structures, in some cases of "levator-humeri abscess," the scapulohumeral joint is extended. This is brought about by flexion of the elbow and carpal joints.
There are some cases of bi-lateral affections which occasion such pain during weight-bearing that the subject shifts its weight from one affected leg to the other; an example of this condition may be observed in any acute case of gonitis which affects both patellar regions, making it equally painful to bear the weight on either member.
A peculiar characteristic position is assumed in acute laminitis of the fore feet. In such instances, the hind feet are brought forward under the body sufficiently to relieve the front feet of the weight, insofar as is possible by the abnormal position taken in cases of acute laminitis.
So in each position that is abnormal to any degree, assumed by a suffering animal, there may be deduced, the fact that the subject is attempting to relieve the affected structures, and in each clinical picture of this kind, the trained diagnostician sees some index to the nature and source of the trouble. Further examination is rendered more effective because of this preliminary visual examination which has precluded the unnecessary annoyance of the animal by manipulating unaffected structures.
It has been presupposed in the foregoing, that the one making visual examination of a lame animal for diagnostic purposes, will remember that with the normal animal the weight is borne equally well with both fore legs; and that this is done without shifting from one to the other; and that the pelvic limbs do not support the body in this manner. Normal subjects shift their weight from one hind leg to the other and the one relaxed, rests in a state of flexion with the toe on the ground and the heel raised.
Examination by Palpation.
In nearly every case where lameness exists an examination of the affected parts, by palpation or by digital manipulation, is necessary before an accurate conclusion may be drawn; but in making this kind of an examination one needs to exercise good judgment lest he fail to acquire a correct impression of the actual existent conditions. There is need for the diagnostician, here, as well as in other conditions where physical examination is made, to approach the subject in a manner that will not excite or disturb to the extent that the animal will, in one way or another, resist or object to the approach of the diagnostician, thereby masking the symptoms sought. The practitioner would best acquire skill as a horseman—if he is not possessed of such—and handle each individual subject in the manner calculated to best suit the temperament of the animal examined. The unbroken subject is not handled as satisfactorily as is the intelligent family horse; in the former, in some cases, little dependence is placed upon digital examination.
By palpation one is enabled to recognize hyperthermia and this, in lieu of dependable history, is at times sufficient evidence upon which to determine the duration of any given inflammatory affection.
By comparison of different parts of the same member or with an analogous portion of another member any marked increase in the apparently normal temperature of a part at once signalizes inflammation. In this manner, in examining a case where laminitis or other inflammation of the feet is suspected, one may arrive at a fairly accurate conclusion without the employment of other means. Throbbing vessels are not always easily recognized if the subject is a victim of chronic lymphangitis.
In some instances, where a moderate degree of lameness exists and cause is apparently obscure, the recognition of hyperthermia may be the deciding factor in establishing a diagnosis. In cases of sprained ligaments in the phalangeal region, because of the dense character of the structures involved, little if any evidence of the cause of lameness, other than local heat, may be found twenty-four hours after the injury has been inflicted.
In order to determine the amount or extent of hyperthermia with a fair degree of accuracy in any given case, one must make due allowance for external conditions affecting temperature; also the effect of a considerable amount of hair covering an area, as well as any possible dirt contacting the surface of the skin must be taken into account. All dirt should be removed if practicable, so that the diagnostician's palms may come as nearly in contact with the inflamed structures as possible. Then, too, the sense of touch if the operator's hands are chilled, is not dependable. In such instances the novice will need to be deliberate as to his findings—whether or not hyperthermia really exists. Such an examination is of little value where the subject's feet are wet and an examination is hurriedly made, as in cases of suspected laminitis.
Often, before being able to distinguish the presence of a hyperthermic condition, one is impressed with the fact that an animal manifests evidence of being supersensitive. In fact, some animals in the anticipation of pain at the touch of an injured part, will instinctively withdraw—in self-protection—such an ailing member or resist the approach of the practitioner. This sensitiveness is more apparent in animals that have been subjected to previous manipulation or treatment which has occasioned pain, and consequently, allowance must be made for this exhibition of fear. No better example of this condition can be imagined than is present in cases of "shoe boil," where there exists an extensive area of acute inflammation of the elbow. There is always more or less surface disturbance wherever vesication has been produced, and in cases where irritants of any kind have been employed for several days or a week previous to an examination, more or less supersensitiveness is to be expected.
One must not lose sight of the fact that unscrupulous dealers,—"traders"—make use of their knowledge of this principle in various way usually for the purpose of attracting attention to a part, which, presumably might have been blistered in order to intentionally produce inflammation of tissues, in this way, causing lameness which is not manifested until an animal has been kept by its new owner for twenty-four hours or more. This, to be sure, usually makes a dissatisfied purchaser who is willing to dispose of his newly acquired animal at a sacrifice, thus enabling the original owner or his agent to regain possession of the victimized animal at less than its real value.
Some nervous animals, because of the manner of approach of the practitioner, are wont to flinch, and there is manifested a pseudo-supersensitiveness. Young animals not accustomed to being handled are likely to be timorous, and one must not hastily conclude that a part is painful to the touch because the subject resents even gentle digital manipulation of such parts. In instances of this kind, one needs to compare sensibility by manipulation of different parts of the subject's body in a careful and gentle manner; and by exercising patience and good judgment in such work, it is possible to actually distinguish between normal sensibility and abnormal sensitiveness, in most cases. Here, again, the diagnostician needs to possess skill as a horseman and good judgment as to individual temperament of different animals, under any condition which may exist at the time he makes his examination.
By palpation alone, one can recognize the presence of fluctuating enlargements; one may not only recognize such conditions, but distinguish between a fluctuating mass such as exists in non-strangulated hernia and a large fibrous tumor. By palpation, for the recognition of density and for determining the presence or absence of hyperthermia, one may decide that there exists an abscess and not a tumor. Edematous swellings are recognized by palpation,—the characteristic indentations which may be made in dropsical swellings are pathognomonic indicators. In this manner it is easy to differentiate post-operative or post-traumatic edemas which may or may not cause lameness. At any rate, it is essential to take into account all determinate conditions that may assist in the prognosis of any given case, for the purpose of being able to outline rational remedial measures. To be able to distinguish between the generalization of a septic infection in its incipiency, and a more or less benign edema, is largely possible by digital manipulation alone. An extremity may be greatly swollen because of the existence of chronic lymphangitis, influenza, or an acute septic infection occasioned by the introduction of pathogenic and aerogenic organisms. Since the effect produced by these dissimilar ailments are productive of conditions that may terminate favorably or unfavorably, it becomes necessary for the diagnostician to develop a trained, discriminating, tactile-digital sense, in order to correctly interpret existing conditions, and handle cases in a rational and skillful manner.
In order to ascertain the extent and exact location of a tumor, an exostosis, or other enlargements, the diagnostician, here also, needs to be in possession of a trained tactile sense and in addition if he be fortified with an accurate knowledge of normal anatomy and pathology, he is able to arrive at proper conclusions, when digital manipulations have been employed. Fibrous tumors are sometimes located in the inferior part of the medial side of the tarsus—exactly over the seat of bone-spavin. Such tumors, when the affected member is supporting weight, are not to be distinguished from exostoses; but as soon as the affected leg ceases to bear weight, it may be passively flexed and the nature of the enlargement recognized because it may be slightly displaced by digital manipulation. Displacement, of course, is not possible with an exostosis.
A necessary qualification, which the diagnostician must possess, is that of being able to judge carefully the nearness of any given exostosis to articular structures. Also, the extent or area of the base of an exostosis as well as its exact position, needs be determined before one may estimate the probable outcome in any case,—whether treatment should be encouraged or discouraged by the practitioner. Periarticular ringbone may, because of the size and location of the exostosis, constitute a condition which cannot be relieved in any way in one case, and in another, because of the manner of distribution of such osseous deposits, the condition may be such that prompt recovery will follow proper treatment. In the examination of an exostosis of the tarsus, it is particularly important to determine the exact location of the exostosis—whether or not the spavin involves the tibial tarsal (astragulus) bone very near its tibial articular portions. Obviously, if articular surfaces of joints are involved, complete recovery cannot result despite the most skillful attention given the subject.
Wherever it is possible to gain the confidence of a tractable animal to the extent that it will relax the structures sufficiently to make possible passive movement of affected parts, much is to be learned as a result of such manipulation. By this method one may differentiate true crepitation, false crepitation, luxation and inflammation of ligaments that have been injured, as in sprains of such structures in the phalangeal region.
True crepitation is recognizable by the characteristic vibration which is interpreted by tactile sense. It is possible to recognize fracture by the use of other methods—auscultation, tuning fork tests, etc., but in ordinary veterinary practice one must rely upon the sense of touch for recognition of crepitation.
Where pain is not so great that relaxation of parts does not occur, one can, by gently moving an extremity in various directions—as in flexion, extension and lateral motion as well as by rotation—cause to be manifested this peculiar grating,—the friction of newly broken bone. This is known as true crepitation. Where the subject, suffering phalangeal fracture, manifests evidence of pain due to tensing the structures about a fractured part, one may anesthetize the parts by using about two cubic centimeters of a two per cent. solution of cocain upon the plantar nerves, proximal to the fracture. It is perhaps best to deposit the cocain solution by means of two hypodermic punctures at different points along the course of each nerve, though closely situated to one another, thereby making more sure of the solution actually contacting the nerve. In some multiple fractures of the first or second phalanx this is quite necessary; otherwise, pain produced by passive manipulation causes the subject to keep the tendons so tense that crepitation may not be detected. The unnecessary infliction of pain is always to be avoided.
We know as false crepitation a vibrating impulse occasioned by normal contact of articular portions of bones such as in the metacarpophalangeal joint when this structure is passively moved, where the subject permits the parts to remain in a state of complete relaxation.
Attempts to recognize supersensitiveness or inflammation by means of passive movement of the shoulder or hip, whether gently or forcefully, is not productive of good, in any case, in large animals. Because of the bulk and weight of parts so manipulated, as well as the resistance the subject offers even in normal cases, no accurate conclusion is to be arrived at in this manner in the average instance. Animals nearly always resist the placing of members in any position that is so unusual and uncomfortable as that which is required to materially displace the component tissues of the shoulder or hip; therefore, such practice is useless because one can not distinguish between normal resistance and flinching caused by painful sensations in injured parts. Such manipulations are practical in small animals.
Observing the Character of the Gait.
In order to determine the degree of lameness as well as its character, it is necessary to cause the subject which is being examined, to move in some manner. The degree of inconvenience or distress experienced by a lame animal that is being so examined is manifested by the character of the claudication; and where much pain is occasioned in locomotion there is disturbance of respiration; perspiration may be noticeable and in some instances manifestation of nervous shock are very evident—this in timid, nervous animals that anticipate being punished when approached and, consequently, make every effort possible to move when urged to do so. An animal, then, should be moved only sufficiently to cause it to exhibit the degree of lameness present in any given case, and if a marked impediment is manifested it is not necessary to cause the subject to be exerted to the extent of inflicting, in such manner, unnecessary punishment. Further or conclusive examination is made by palpation. To cause the subject to move, an assistant may simply lead the animal with a halter and compel it to walk a few steps. In this way, lameness, whether manifested during the weight-bearing period of an affected member, or when such a member is being advanced, or whether a combination of the two conditions exists, is made apparent. In the words of Dollar, one is thus enabled to recognize the existence of "supporting-leg-lameness," "swinging-leg-lameness" or "mixed lameness."
When the cause of lameness is not strikingly apparent it becomes necessary to have the subject moved farther than a few steps and at different paces. Depending then, upon the character of lameness manifested, as well as upon its degree of intensity, one needs to exercise the subject in various ways, but this should not be overdone.
The first thing apparent in the lame subject in action, is the lame leg. If this is not readily determinable, as in some complicated cases, the leg or legs which are at fault are to be discovered by further examination, and to do this,—word-pictures convey little that is helpful in difficult cases,—long practice is the one route by which one may become efficient; that is, by experience gained after fundamental principles in the diagnosis of lameness have been mastered.
For a careful study of supporting-leg-lameness involving a fore limb, the subject is driven or led toward the one making such examination. If a hind leg is to be observed, the animal is made to travel away from the examiner. Where there exists swinging-leg-lameness, the subject should be caused to move past the diagnostician, so that he may get a side view of the subject while it is in motion.
In every case such examinations are made to the best advantage if the practitioner can view his patient from a little distance. Here, again, a visual examination is made but this cannot be successfully executed, in difficult cases, if the practitioner is stationed at too close range.
The average subject is best observed by being led, rather than being ridden, and in so doing the animal should be given moderately free rein. A close grasp on the lead may interfere somewhat with head movements. Nodding of the head with the catching up of weight by a sound member in supporting-leg-lameness of a fore leg, constitutes the chief symptom considered in detecting the lame leg.
Where supporting-leg-lameness affects a hind limb the head is raised at the time weight is caught by the sound member—here the long axis of the subject's body may be likened unto a lever of the first class. The posterior part of the body, at the time weight is taken upon the sound leg, is as the long arm: the fore limbs the fulcrum, and the subject's head the weight, which is lifted. The head movements of a horse at a trot, in supporting-leg-lameness of a front leg, synchronize with the discharge of weight from a lame leg to the opposite one if sound; but in pelvic limb affections, the head is thrown or jerked upward as weight is caught by the sound member,—this peculiar nodding movement is opposite in the two instances.
In pacing horses, since front and hind legs of the same side are advanced at the same time, there occurs in supporting-leg-lameness, a nodding of the head with discharge of weight from the lame leg, and a dropping of the hip as weight is caught by the sound pelvic member. In observing animals that are limping, (as in supporting-leg-lameness) one notices particularly the sacro-iliac region in hind leg affections and the occipital region in lameness of the front legs.
Where there exists a bilateral affection, (such as characterizes some cases of navicular disease or other affections causing supporting-leg-lameness) there occurs no nodding of the head; weight is supported for an equal length of time upon each one of the two legs, but the stride is shortened. The gait, in such cases, is peculiar, animals appearing stiff and they are said, by horsemen, to have a "choppy" gait.
It is desirable, in some cases, to cause an animal to move from side to side; in other instances the subject is best made to walk or trot in a circle, and if the circle be very small the animal then particularly employs the inner fore leg as a pivotal supporting member. To augment the manifestation of certain affections, it is necessary to cause the patient to walk backward, and each one of these tests of locomotion serves to point out in a more or less characteristic manner, the site of the affection which is causing lameness in different cases.
Sprains or injuries of lateral ligaments of the extremities, ringbone and certain foot affections, are made manifest by a side to side movement or a pivotal movement. In fact, wherever it is possible to cause undue or unusual tension to be exerted upon an inflamed structure, manifestation of pain is the response. In an inflamed condition of the lateral side of the phalanges, unequal weight-bearing such as a rough road surface will, by virtue of the leverage which the solar surface of the foot affords, cause undue strain upon such inflamed parts, and increased lameness is evident.
When an animal is made to travel in a circle, when a member affected with supporting-leg-lameness is on the inner side of the circle, lameness is accentuated because weight is borne by the lame leg for a greater length of time, the result of such circuitous manner of locomotion. In swinging-leg-lameness, on the other hand, because pain is increased at the time an affected member is being advanced, lameness is increased when the subject is made to travel in a circle, with the lame leg on the outside of a circle thus described.
In supporting-leg-lameness, the transientness of the weight-bearing period upon the affected member is the determining factor in the production of lameness. This unequal period of weight-bearing upon the front legs, for instance, causes an acceleration in the advancement of the sound member, in order to relieve the diseased one which is bearing weight. In other words, when an animal that is affected with supporting-leg-lameness travels in a straight line, since weight is borne by the diseased leg for an abnormally short period of time, the sound member needs be in the act of advancement a correspondingly short period. The result is then, an unequal division of stride; a nodding of the head with the catching up of weight by the sound leg,—in front leg affections—and this is termed limping.
With continuous exertion as in travel for a considerable distance, in some cases, lameness becomes less evident—as in spavin. This "warming out" process is due in a measure to the parts becoming less sensitive upon exertion, and is to be seen, to a limited extent, in all inflammatory affections that are not too severe; consequently, in some cases, examination of a lame animal should begin in the stall, for in instances where the impediment is not marked, there may be no evidence of lameness after the subject has walked a few steps. In other cases, lameness increases as the subject continues to travel, and often to the extent that the impediment becomes too severe to allow the animal being serviceable. Therefore, one can not, in every case of lameness observed, positively determine the gravity of the situation, without having seen the affected animal in action for a sufficient length of time to understand the nature of the condition existing. This necessitates driving the animal for several miles in certain cases.
Sometimes it is impossible to arrive at any definite conclusion, as the result of a single examination, and it then becomes necessary to see the subject again at a later date, or under more favorable circumstances. This is to be expected in some conditions where there exists rheumatic affections, and also in some foot diseases.
In the examination of young animals, unused to harness and to other strange incumbrances, one is obliged to make allowance for impediments of gait, which are not occasioned by diseased conditions. Such affections have been termed "false lameness." Young mules that are not well broken to harness, are difficult subjects for examination and in some cases it is necessary to have them led or driven for a considerable distance before one can definitely interpret the nature of the impediment in the gait when lameness is not pronounced. It is especially difficult to satisfactorily examine such subjects, for the reason that their normal rebellious temperaments cause resistance whenever a strange person approaches them, as it is necessary to do for an examination by palpation. In such cases—if an examination does not reveal the cause of trouble, rest must be recommended and further examination made at a later date, whereupon any new developments may be noted, if such changes exist.