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The cul-de-sac of the capsular ligament of the fetlock joint which extends upward between the bifurcation of the suspensory ligament is the most frequently affected structure in this region. When distended, two spheroidal masses bulge laterally and anterior to the flexor tendons in a characteristic manner. This condition is known among horsemen as "wind-gall" or "fetlock-gall."
The sheath of the flexor tendons, which begins about the middle portion of the lower third of the metacarpus, and continues downward below the pastern joint is often distended.
Excepting in cases of acute inflammation attending synovitis of these parts, no lameness marks its existence and in chronic cases of synovial distension the service of affected animals is not interfered with. These distensions constitute unsightly blemishes and they are treated chiefly for this reason.
No difficulty is encountered in recognizing these conditions even where considerable organization of tissue overlying distended thecae occurs. In such cases there may be only slight fluctuation of the enlargement, but if necessary, an aseptic exploratory puncture may be made with a suitable needle or trocar.
Treatment.—Complete rest and the local application of cold packs are in order in acute synovitis when there is distension of tendon sheaths. In the fetlock region, because of the ease with which pressure may be employed, the parts should be kept snugly wrapped with cotton, and derby bandages are used to exert the desired amount of pressure over the affected region. The pressure-bandages should be employed as soon as all acute and painful inflammation has subsided; and then they should be continued, day and night, for ten days or two weeks. The bandages should be removed morning and night. After the skin of the leg has thoroughly dried off, an infriction of alcohol or distilled extract of hamamelis is given the parts and the cotton and bandages are readjusted. A good, even and firm pressure in such cases is productive of satisfactory results.
In chronic distensions of tendon sheaths synovia may be aspirated and about five cubic centimeters of equal parts of tincture of iodin and alcohol is injected into the cavity. This is not done, however, without usual aseptic precautions. If no marked swelling results within forty-eight hours the entire fetlock region is thoroughly vesicated and, as soon as the skin has recovered from the effects of the vesicant, pressure bandages may be employed. In these cases, subjects may be put into service after all swelling which the injection or the vesicant has produced has subsided. The pressure bandages are used at night or during the time that the horse is in its stall and they are not worn by the subject while at work.
Where no marked swelling occurs within ten days, as the result of the injection of iodin, the injection may be repeated and, if thought necessary, the quantity may be materially increased. If swelling does not occur it is indicative that no particular irritation has been caused.
Some swelling is desirable and much swelling sometimes results and persists for weeks. This is not in any way likely to cause permanent trouble; and if the technic of injection is skilfully executed no infection will follow.
By persistent and careful use of suitable elastic bandages, the support thus given the parts, together with the absorption of products of inflammation which constant pressure occasions, some chronic cases of synovial distension of tendon sheaths recover in two or three months and this without other treatment. Such good results are not to be expected in aged subjects, nor in horses having at the same time, chronic lymphangitis.
Where bandages of pure rubber are employed great care is necessary, if one is not experienced in their use, lest necrosis result. Where bandages are uncomfortably tight the subject will manifest discomfort, and an attendant should observe the animal at intervals for a few hours (where there may be some doubt as to the degree of pressure which is exerted by elastic bandages) and readjustment made before any harm is done.
Arthritis of the Fetlock Joint.
Anatomy.—The anatomy of the metacarpophalangeal articulation is briefly reviewed on page 58 under the heading of "Anatomo-Physiological Review of Parts of the Foreleg."
Etiology and Occurrence.—The chief causes of non-infective arthritis of the fetlock joint are irritations from concussion and contusions due to interfering. The condition occurs in young animals that are over-driven in livery service or other similar exhausting work, where they become so weary that serious injury is done these parts by striking the pasterns with the feet—interfering. In these "leg-weary" animals, that are always kept shod with fairly heavy shoes, much direct injury is done at times by concussion due to self-inflicted blows. In older animals, where there exists similar conditions, with respect to their being worn from fatigue and, in addition, periarticular inflammatory organizations, arthritis is not of uncommon occurrence.
Symptomatology.—In true arthritis there exists a very painful affection which is characterized by manifestations of distress. The subject may keep the extremity moving about—where pain is great—suspended and swinging. There is swelling which is more or less hot to the touch and compression of the parts with the fingers increases pain. Lameness is always pronounced and no weight is supported with the affected member in very acute and generalized arthritic inflammations. There occurs the usual facial manifestations of pain—the tense condition of the facial muscles and the fixed eye and nostril are in evidence.
In cases where there exists a synovitis or where a very limited portion of the articulation is involved, a somewhat different clinical picture is presented. Then, the disturbance causes less distress; local swelling and evidence of supersensitiveness are not so pronounced and lameness is not intense, though weight-bearing is painful.
Prognosis.—There is a constant difference in the degree of pain manifested, as well as the other symptoms of inflammation, between true arthritis, which involves much of the joint, and synovitis; or synovitis plus a small circumscribed area of joint involvement. This difference is present in all joint affections of the extremities and, in passing, it is well to say that infection usually increases every manifestation of pain. Infection occasions more pronounced local symptoms of inflammation and, because of the rapid progress of necrotic destruction of cartilage, the course of the affection is usually rapid; ankylosis is a frequent result and loss of the subject is often inevitable. However, in non-infective arthritis of the fetlock joint, prognosis is favorable.
Treatment.—The same general principles which are employed in arthritis of other joints are used here. Rest and comfort for the patient is sought in every available manner. If the subject remains standing too long, the sling should be used and a well-bedded box-stall will contribute much to the comfort of the patient.
Pain and acute inflammation is diminished or controlled, if possible, by using ice-cold packs. In nervous, well-bred animals analgesic agents may be employed; or small doses of morphin sulphate—one to two grains—given at intervals of three hours during the first stages of the affection is very beneficial. This is especially indicated in infectious arthritis.
As inflammation subsides, hot applications are used and finally counter irritants are employed. Their selection is a matter of choice with the practitioner. The object sought is the same with every practitioner and while methods employed vary, results are not markedly different except in so far as the degree of counter irritation which is produced varies in given cases. Where a great degree of counter irritation is thought necessary, line-firing with the actual cautery is the remedy par excellence.
After-care.—In the course of three or four weeks subjects may be allowed the run of a paddock and, after a complete rest of six weeks at pasture, they may be returned to work with care, if the work is not of a nature to occasion concussion or other manner of irritation to the articulation.
Neurectomy is not indicated even though there is a recurrence of lameness, unless the lameness is not pronounced and inflammation is periarticular and no osseous enlargements mechanically interfere with function of the joint. There are few cases then, where neurectomy is materially helpful.
Ossification of the Cartilages of the Third Phalanx. (Ossification of the Lateral Cartilages.)
Anatomy and Function of the Cartilages.—Surmounting each wing of the distal phalanx (os pedis) is the irregularly-quadrangular cartilage. The superior border of this cartilage is thin, generally convex, and perforated for vessels to pass to the frog; the inferior border is attached to the wing of the third phalanx and posteriorly, it is reflected inward and is continuous with the inferior surface of the sensitive frog. The anterior border which is directed obliquely downward and backward becomes blended with the anterior lateral ligament of the coffin joint. The fibrous expansion of the anterior digital extensor (extensor pedis) is united to the anterior borders of the lateral cartilages.
According to Smith[27]: These structures form an elastic wall to the sensitive foot, and attachment to the vascular laminae; they also admit of increase in width occurring at the posterior part of the foot without destroying the union of the two set of leaves. Further, by their connection with the vascular system of the foot, their elastic movements materially assist the circulation. The primary use of the lateral cartilages is to render the internal foot elastic, and admit of its change in shape which occurs under the influence of the weight of the body. The alteration in the shape of the foot is brought about by pressure on the pad, which widens and in consequence presses on the bars. The pressure received by the pad is also transmitted to the plantar cushion, which likewise flattens and spreads under pressure. Both of these factors force the cartilages slightly outwards. When the posterior wall recoils the cartilages are carried back to their original position. Should the elastic cartilage under pathological conditions become converted into bone, its functions are destroyed, and lameness may occur.
Etiology and Occurrence.—The causes of ossification of these cartilages are several. No doubt there exists a predisposition to this condition for it is of such frequent occurrence in heavy draft types of horses. Concussion plays an important role and, according to Moeller's[28] theory, which is sound, high heel calks prevent the frog from contacting the ground, and as weight is placed upon the foot "the lateral cartilages are subjected to a continuous inward and downward dragging strain."
The condition affects the cartilages of the fore feet more frequently than those of the hind and the outer cartilage is more often ossified than is the inner. This fact may be accounted for by its more exposed position; it is also frequently injured by being trampled upon and otherwise contused or cut, as in lacerated wounds of the quarter.
Symptomatology.—Ossification of the cartilages is known by grasping the free borders with the fingers and attempting their flexion; the rigid inflexible ossified cartilage is thus easily recognized.
Lameness during weight-bearing occurs in the majority of cases at some time. Much depends on the conformation of the foot and whether the involvement affects one or both cartilages as to the degree and duration of lameness which marks this affection. In narrow and contracted heels it is reasonable to expect more lameness than in well formed feet. Where only one cartilage is ossified, the other being flexible, there is less inconvenience experienced by the subject during weight-bearing, because of the expansion of the heel which the one normal cartilage allows.
Treatment.—There is little if anything to be done in case the cartilage has become ossified except to shoe without high calks but preferably with rubber pads. The hoof should be kept moist; the wall at the quarter may be rasped thin and kept anointed. Firing is of no practical benefit in these cases, and it is doubtful if vesication is helpful excepting where only a part of the cartilage is ossified.
Subjects which continue somewhat lame, because of complete ossification of both cartilages, are best put to slow work on soft ground and not driven on pavements.
Navicular Disease.
This more or less ambiguous term has been applied to various diseases affecting the structures which make up the coffin joint. We consider this name to be applicable to inflammatory involvement of the third sesamoid (navicular bone), the deep flexor tendon (perforans) and the bursa podotrochlearis or navicular bursa.
Etiology and Occurrence.—In 1864 Thomas Greaves[29] wrote on the subject of navicular disease as follows: "The opinion I entertain upon the subject of navicular disease is, that in by far the greater majority (if not all) of these cases there exists in the animal affected a congenital tendency or predisposition, that, generally speaking, it is the high stepper, the good goer, that becomes the victim to this disease; and it is a fact well attested, that it as frequently develops itself in the feet with wide frogs, bulbous heels, shallow heels, spread flattish feet, as in the narrow upright feet.... I have known foals, born from defective parents, in which this condition was so strongly developed, that all men would at once pronounce them affected with navicular disease, and such lameness was permanent."
Often both fore feet are affected and this would point toward its being a disease wherein either conformation or congenital tendencies exists. It is rare that hind feet are involved.
There are many theories regarding the possible exciting causes of navicular disease and, when one has carefully considered the explanations as offered by Peters, Moeller, Branell, Schrader and others, he may conclude that navicular disease is a non-infectuous inflammatory affection of the third sesamoid (navicular) bone, deep flexor tendon (perforans) and adjoining structures. Whether it originates in the flexor tendon or whether the bone is the original part affected, the disease is frequently met, and of all possible causes, jars and irritation incident to concussion of travel, are probably the principal causative agents.
Symptomatology.—Lameness is the primary indicator and a constant symptom which attends navicular disease wherever much structural change affects the infirm parts. As the degree of intensity or extent varies, so is there a dissimilarity in the character of the impediment. Incipient cases of bilateral involvement are more difficult to diagnose than are unilateral affections, particularly when lameness is not marked. There is manifested a supporting-leg-lameness which varies as to degree in the same subject at different times. This may be noticed during the same trip in an animal that is being driven. There is a tendency for the subject to stumble and, of course, where the affection is bilateral, there is a stilted gait owing to shortened strides.
At rest the lame animal usually points with the affected member. Because of the fact that the distance is lessened between the origin and insertion of the deep flexor tendon (perforans) by this attitude, one may readily understand the reason for the position assumed by the subject. Pressure on the navicular bone is diminished and tension on the flexor tendon is relieved by even slight volar flexion.
In acute inflammatory affections abnormal heat may be detected in the region of the heel. By exerting tension on the flexor tendon, by means of passive dorsal flexion of the member, evidence of hyperesthesia may be detected. With the hoof testers one may determine supersensitivenss in most instances. There occurs more or less contraction of the hoof in navicular disease, but this is not to be taken as a cause of the affection, but rather a sequence.
In some cases of unilateral navicular disease there is a marked contrast in size between the sound and unsound foot. However, one must not be misguided in this particular, for in some pairs of sound feet there exists considerable difference in size. Finally, by a change from the normal position of the foot to one in which the heel is somewhat elevated (as may be obtained by shoeing with high heel calks), relief is evident, and in the opposite position, the condition is aggravated. This experiment may be used for diagnostic purposes.
Treatment.—When the anatomy of the diseased parts is taken into consideration, and an analysis of the lesions which occur in cases where considerable structural change is occasioned by this affection, it is obvious that recovery is impossible. Only in cases where the inflammation is promptly checked before damage has been done the navicular bone or the flexor tendon, is permanent recovery possible. The disease is not frequently treated during this stage, however, and in the majority of instances the condition becomes chronic.
As soon as a diagnosis is made the shoes must be removed, the toe shortened with the hoof pincers and rasp and the subject is put in a well bedded box-stall. If the animal is very lame and the inflammation is acute, ice-cold packs should be applied to the feet. As soon as acute inflammation has subsided the foot may be so pared that all excess of sole and frog is removed without lowering the heels, and the animal may be blistered about the coronet region. The subject may be shod later, with heel calks that raise the heel moderately and a protracted period of rest should be enforced.
In cases where no acute inflammatory condition exists, neurectomy is beneficial. One must discriminate, however, between favorable and unfavorable subjects. This is not a last resort expedient to be employed in cases where extensive lesions of the navicular structures exists. With proper shoeing, and by putting the subject at suitable work, where concussion of fast travel on hard roads is not necessary, the best results are obtainable.
Laminitis.
This disease is primarily a non-infective inflammation of the sensitive laminae which very frequently affects the front feet. Often all four feet are affected, less frequently one foot (when its fellow is unable to sustain weight) and rarely the hind feet alone.
Occurrence.—Probably a greater number of cases of laminitis occur in localities where horses that are worked on heavy transfer wagons are, when in a state of perspiration, allowed to stand exposed to sudden lowering of temperature and to stand in a cool or cold shower of rain such as occurs near the coast of the Great Lakes or the ocean in some parts of this country.
This disease occurs in connection with digestive disorders of various kinds and, because of the frequent association of the two conditions, the common term "founder" has long been employed to designate laminitis. In cases of "over-loading," particularly when a large quantity of wheat has been eaten by animals that are unaccustomed to this diet, laminitis almost constantly results.
Large draughts of cold water, when drunk by animals that are overheated is often followed by laminitis. Concussion, such as attends hard driving, especially in unshod horses or on rough and hard roads, is often succeeded by this affection. Likewise, as has been stated, injury such as is occasioned by long continued standing on the same foot is followed by laminitis. Some horses that are frequently shod, suffer from this affection a few hours after shoes have been reset. Dr. Chas. R. Treadway of Kansas City reports the rather frequent occurrence of such conditions in horses that are in the fire department service in his city.
Age in no way influences the occurrence of laminitis and the general condition of an animal with regard to its vigor or state of flesh has no apparent influence toward predisposing horses to this ailment.
Etiology and Classification.—As it is with some other diseases, one may unprofitably theorize on cause and readily enumerate many conditions which are apparently contributory toward producing the affection. Causes may well be grouped, however, and a more definite understanding of laminitis is possible as a result. Such collocation would include conditions which directly or indirectly affect the digestion, such as puerperal laminitis, drinking of large quantities of cold water and exposure to cold and rain when the body is warm. All of these various conditions might be said to affect the vaso-constrictor nerves in such manner that the natural tendency (because of the peculiar structure of the sensitive laminae and their mode of attachment to the non-sensitive wall) which solipeds have for this affection is indirectly due to this one cause—vaso-constriction. According to Dr. D.M. Campbell, the effect of toxic materials, which may be absorbed from the digestive tract or the uterus in parturient females, upon the vaso-constrictor nerves, is such that a passive congestion of the sensitive laminae occurs and laminitis is the result. He believes that even the chilling of the surface of the body when very warm, by a cold rain, constitutes a condition wherein the effect upon the vaso-constrictors is the same.
This grouping does not include the effect of direct injuries of any and all kinds to which the feet are subjected such as: Concussion in fast road work, injuries occasioned by tight or ill fitting shoes, contusions of any kind resulting in non-infectious inflammation of the sensitive laminae, as well as the causes which produce laminitis where weight is borne by one foot when its fellow is out of function.
A classification which is practical is that of acute and chronic laminitis. To the practicing veterinarian it is this manner of consideration that is essential in the handling of these cases.
Symptomatology.—In the acute attack the condition is so well described by Dr. R.C. Moore[30] that we quote him in part as follows:
The acute form is generally ushered in very suddenly. Often a horse that is perfectly free from symptoms of the disease is found a few hours later so stiff and sore that he will scarcely move. They stand like they were riveted to the ground. If forced to move the evidence of pain subsides to some extent after they have gone a short distance, to return more severe than ever after they have been allowed to stand for a short time. If the disease is confined to the two front feet, the hind feet are placed well under the center of the body to support the weight and the front ones are advanced in front of a perpendicular line so as to lessen the weight they must bear. If they are made to move, the same position of the feet is maintained. If made to turn in a small circle, they do so by using the hind feet as a pivot, bringing the front parts around by placing as little weight on them as possible.
Placing the hind feet so far under the body, arches the back and often leads to errors in diagnosis, the condition sometimes being taken for diseases of the loins or kidneys.
If all four feet are involved, the animal stands in the usual position assumed in health, but if urged to move, the least effort to do so usually brings on chronic spasms of the entire body. In very severe cases, a slight touch of the hand will develop the spasms. At times they are so severe, and have such short intermissions, that the disease has been mistaken for tetanus. However, the clonic nature of the spasm should prevent such an error. If they are lying down, it is difficult to get them to arise, and if they do so, they show marked symptoms of pain for some time after rising.
If the disease is confined to the hind feet, they are placed well forward to relieve the strain on the toe caused by the downward pull of the perforans (deep flexor) tendon, but in place of the front feet being kept in front of a perpendicular line, as they are when the disease is confined to the front ones, they are placed far back under the body, so they will carry the maximum share of the body weight of which they are capable. The position of the feet is of great importance and offers symptoms that should not be overlooked.
When the subject is caused to walk, symptoms of excruciating pain are manifested in all acute cases of laminitis. In some cases where all four feet are affected, no reasonable amount of persuasion will cause the suffering animal to move from its tracks.
There is acceleration of the rate of heart action; the pulse is full and in some cases, bounding. As the affection progresses the pulse becomes rather weak and irregular. The character of the pulse in the region of the extremity is a reliable indicator; but one has to learn to make necessary discrimination because of the condition of the parts, as in some cases of lymphangitis or where the skin is abnormally thick. The characteristic throbbing pulse is, however, easily recognized in most cases. Temperature is variable, though usually elevated from one to four degrees above normal. This symptom varies with the type and stage of the affection. In a subject that has been down, unable to rise for several days, where there is a suppurative and sloughing condition of the laminae, the temperature is high. Whereas, in some other and less destructive cases there may be little thermic disturbance after the first few hours have lapsed.
A constant symptom in bilateral affections of acute laminitis is the difficulty with which the subject supports weight with one foot. It is this which causes the victim to stand as if "rooted to the ground" when all four feet are involved. If one attempts to take up one foot, thus causing the subject to stand on the other, there is much resistance and in many cases the animal refuses to give the foot.
When we consider that the sensitive parts of the foot are encased by a horny, unyielding box and that, when the laminae are congested, a great pressure is brought to bear upon the sensitive structures, it is easy to understand why the condition is so painful.
Chronic laminitis is a sequel of acute inflammation of the sensitive laminae. It varies as to intensity and the exact manner of its manifestation depends upon preexisting disturbances.
In some mild cases of laminitis there are recurrent attacks wherein no particular structural change exists, and diagnosis is established chiefly by noting the character of the pulse at the bifurcation of the large metacarpal (or metatarsal) artery just above the fetlock. The same manifestation of pain is present when weight is supported by one foot, though in a lesser degree. There is less local heat to be detected by palpation than in the acute cases.
Chronic laminitis as it occurs following acute attacks which have resulted in structural changes of the foot, present the same symptoms just described and, in addition, the peculiar alterations in structure exist. When, owing to acute inflammation of the sensitive laminae, there has resulted necrosis of this sensitive tissue together with infiltration between the anterior surface of the distal phalanx (os pedis) and the contacting hoof, the lower portion of the distal phalanx is turned downward and backward (rotated upon its transverse axis). Because of the traction which is exerted by the deep flexor tendon (perforans), as it attaches to the solar surface of the distal phalanx, this rotation is facilitated. With hyperplasia of lamina, at the anterior portion of the distal phalanx, there results a thick "white line." Rotation of the distal phalanx necessitates a descent of its apical portion and there occurs a "dropped sole."
In time, partly because of excessive wear of hoof at the heel, owing to an altered condition in the normal antagonistic relation between the flexor and extensor tendons, the toe makes an excessive growth, and the concavity of the anterior line is accentuated owing to this abnormal length of hoof. The hoof, because of recurrent inflammatory attacks, is corrugated—elevations of horn in parallel rings are usually present.
Animals that are so affected in traveling strike the heel first and the toe is later contacted with the ground surface. Rotation of the distal phalanx upon its transverse axis produces a condition, with respect to this peculiar impediment, that is equivalent to added and excessive length of the deep flexor tendon.
Where there occurs suppuration, by careful inspection of the coronary region, one may early recognize detachment of hoof. In such cases animals remain recumbent and, while the condition is not so painful at this stage, the practitioner must not overlook the real state of affairs. History, if obtainable, will be a helpful guide in such cases. Separation of hoof occurs as a rule in from four to ten days after the initial attack of acute laminitis. Needless to say these cases are hopeless, when the economic phase of handling subjects is considered.
Treatment.—Much depends upon the concomitant disturbances (or causes if one is justified in referring to them as such) as to the manner in which laminitis is to be treated. In all cases where digestive disturbances exist, the prompt unloading of the contents of the alimentary canal is certainly indicated. D.M. Campbell[31] in a discussion of laminitis has the following to say regarding the treatment of such cases:
Because superpurgation may be followed by laminitis, the advisability of using the active hypodermic cathartics is questioned. Neither arecolin nor eserin can cause superpurgation. The action of the former does not continue longer than an hour after administration and of the latter not more than eight hours. The action of either is mild after the first few minutes.
I do not think that anyone has recommended either arecolin or eserin where there is severe purgation. Where the intestinal canal is fairly well emptied and its contents fluid, I should be inclined to rely upon intestinal antiseptics to hold in check harmful bacterial growth.
The use of alum in the treatment of laminitis is held to be without reason other than the empirical one that it is beneficial. If laminitis is due chiefly to an autointoxication, good and sufficient reason for the administration of alum can be shown based upon its known physiological action. It is the most powerful intestinal astringent that I know of and has the fewest disadvantages. I have not noted constipation following its use nor diarrhea, nor a stopping of peristalsis, nor indigestion, and in any case its action lasts at most only a few hours, and if it did all these, it could not much matter. Quitman says, that it constricts the capillaries. If this is true, a thing of which I am not certain, is it not reasonable to suppose that as with other vaso-constrictors, e.g., digitalis, there is a selective action on the part of the capillaries (not of the drug) and those that need it most, i.e., those of the affected feet in laminitis, are constricted most? All body cells exert this selective action in the assimilation of food, the tissue needing most any particular kind of food circulating in the blood, gets it.
Our first consideration in laminitis should be to remove the cause—to stop the absorption of the toxin in the intestinal tract that is producing the condition. This we accomplish by partially unloading it by the use of the active hypodermic cathartics and stopping absorption by the surest and most harmless of intestinal astringents. Whether the astonishingly prompt and certain action of alum in this case is due wholly to its astringent action or whether alum combines with the harmful bacterial products chemically and forms an innocuous combination, I can only surmise, and it is unimportant. At any rate, when alum is administered, the onslaught of the disease is promptly stopped. Irreparable damage may already have been done if the case is a neglected one, but whether administered early or late in acute attacks, the progress of the disease is stopped immediately.
The same authority may be profitably quoted in the matter of handling all cases wherein the revulsive effect of agents which diminish vascular tension are chiefly indicated or necessary as adjuvants. In this connection, Campbell says:
The early and vigorous administration of aconitin in laminitis to its full physiological effect, is more logical. Assuming that laminitis is due to absorption of harmful products from the intestinal tract permitted through the deranged functioning of the organs of digestion, or assuming that it is due to an extension of the inflammation from the mucosa to the sensitive lamina, or that it is a reflex from a sudden chilling of the skin, we have in any of these conditions a disturbed circulation, and aconitin is the first and foremost of circulation "equalizers." Furthermore, in laminitis there is an elevation of the temperature, an almost invariable indication for aconitin. A speedy return of the temperature to normal, a very marked diminution of the pain and improved conditions generally, appear coincident with the symptoms of full physiological effect of aconitin when given in cases of laminitis, which constitutes assuredly an important part of its treatment.
Where lameness is not great as in cases wherein no marked structural change of the foot has occurred, proper shoeing is very beneficial. By keeping the heels as low as possible and shoeing without heel calks a more comfortable position is made possible. Thin rubber pads which do not elevate the heel are of service in diminishing concussion.
Dr. David W. Cochran of New York City has attained unusual success in cases of chronic laminitis with dropped sole by the use of a specially designed shoe.
Cochran claims that, not only are horses with dropped soles that would otherwise have to be put off the streets enabled to do a fair amount of work by means of this shoe, but that continually wearing it, meanwhile keeping the convexity of the front of the hoof rasped thin, in time brings about a marked improvement, and that after some months or years of use the animals are able to work with ordinary rubber-pad shoes, provided they are arranged to facilitate breaking over.
From having been successfully used on some race horses of high value, the Cochran shoe has attained considerable notoriety and is being used by a number of practitioners. A disadvantage, however, arises from the fact that few horseshoers other than Doctor Cochran seem able to make the shoe, the peculiar shape of which offers considerable difficulty in forging. Concerning the application of the shoe Cochran[32] says:
"The most important primary procedure is the preparation of the foot to receive the shoe. All excess of growth must be removed from the anterior face of the hoof. The outer face must be reduced at the toe (not shortened), but rasped down thin for the lighter the top of the foot is, the more chance the sole and coffin bone will have of resuming their former normal position. The pressure of the wall at the toe upon the exudate between wall and coffin bone, tends to force the coffin bone and sole out of their normal position. Leave the sole alone. You can lower the excess of growth at the heels.
"There are many designs of shoes to relieve this condition. A great deal depends on the judgment of the shoer to meet the conditions presented, depending on the degree of the convexity and strength of the sole. In some cases we use a shoe that admits of a large amount of sole room. Again, we shoe with a shoe of wide cover. In other cases a shoe with even pressure over the whole sole. In some cases a high, narrow shoe, resting only on the wall, or the ordinary plain shoe with side calks welded close to the outside edge and the shoe dished well from these as a foundation. Then we have the air cushion pad designed after the model of the bowl shoe."
In cases when slight and persistent lameness interferes sufficiently to prevent using an animal at any sort of work on hard roads, median neurectomy will relieve all lameness in most instances. This is a safe operation, moreover, in that no bad after effects are to be feared, even though lameness were to continue.
Calk Wounds. (Paronychia.)
Etiology and Occurrence.—Injuries of various kinds are inflicted upon the coronary region but usually they are due to the foot being trampled upon. When the foot that inflicts the injury happens to be unshod, a contusion of the injured member is occasioned, but in the majority of instances, wounds that demand attention are the result of shoe calks which have penetrated the tissues in the region of the coronary band. Often calk wounds are self-inflicted. When animals are excited and in turning crowd one another, they often perform dancing movements which frequently result in deep calk wounds of the coronet. Some horses have a habit of resting the heel of one hind foot upon the anterior coronary region of the other. While sleeping in this position, if they are suddenly awakened, the weight is abruptly shifted to the uppermost foot and the one underneath is (because of the pain attending its being wounded) quickly drawn out from under its fellow. In this way deep cuts may divide the coronary band and inflict extensive injury to the sensitive lamina as well.
An infectious type of coronary inflammation occurs in some localities during the winter months, wherein the condition is enzootic.
Symptomatology.—Depending upon the manner in which the injury has been produced, the appearance of the wound varies and likewise lameness is more or less pronounced. If the tissues are not divided and the wound is chiefly of the subsurface structures, there will not immediately occur pronounced local evidence of the existence of injury; but as soon as the lame animal is made to move, the peculiar character of the impediment (supporting-leg lameness with the affected foot kept well in advance of its normal position) directs attention to the extremity and all of the symptoms of acute inflammation are discovered.
Where a wound is inflicted which divides, in some manner, the surface structures (skin, coronary band, or the hoof wall) one's attention is at once called to the existence of the wound.
Because of the fact that there is every facility for the production of a sub-coronary and podophylous infection, these wounds should receive prompt attention. In some instances, the pastern joint is opened by calk wounds and then, of course, an infectious arthritis succeeds the injury.
Treatment.—In all contused wounds of the coronary region the parts need thorough cleansing; the hair, if long is clipped and a cataplasm is applied. Or preferably, an iodin-glycerin combination of one part of iodin to four parts of glycerin is poured on a layer of cotton, and this is confined in contact with the inflamed parts by means of a bandage.
Where normal resistance to infection obtains, the subject usually suffers no suppurative disturbance when the surface structures are not broken; and daily applications of the antiseptic lotion above referred to stimulates complete resolution. This may be expected in from four to ten days depending upon the extent of the injury.
If a calk wound has been inflicted, the adjoining surface structures are freed of hair and the parts cleansed in the usual manner, (which in wounds recently inflicted, should be done without employing quantities of water) and after painting the wound surface with tincture of iodin and saturating its depths with the same agent, the wound is cleansed, if it contains filth, by means of a small curette. By using a small and sharp curette, one is enabled to cleanse the average wound quickly and almost painlessly.
In such cases, equal parts of tincture of iodin and glycerin are employed. The wound is filled with this preparation and a quantity of it is poured upon a suitable piece of aseptic gauze or cotton and this is contacted with the wound. The extremity is carefully bandaged and this dressing is left in position for forty-eight hours unless there occurs, in the meanwhile, evidence of profuse suppuration—which is unusual.
One is to be guided as to the progress made by the degree of lameness present. If little or no lameness develops, it is reasonable to expect that infection has been checked; that the wound is dry and redressing every second day is sufficiently frequent.
Where cases progress favorably, recovery (unless infectious arthritis results) should occur in from ten days to three weeks. Where extensive sub-coronary fistulae result, either from lack of prompt or proper attention, the condition is then one requiring a radical operation to establish drainage and to disinfect if possible, the suppurating tissues.
Corns.
Etiology and Occurrence.—In horses, because of a tendency toward contraction of the heel in some subjects, together with work on hard roads and pavements, where the feet become dry and brittle, and because of neglect of the matter of shoeing, this affection is of frequent occurrence. Unshod horses are rarely affected. If conformation is faulty and too much weight is borne on the inner or the outer quarter, and the hoof wall at the quarter tends to turn inward, corns are usually present. They occur more frequently on the inner quarters of the front feet, though the outer quarters are occasionally also affected and in rare instances corns are found at the toes. They do not often affect the hind feet.
As soon as injury by pressure, such as is supposed to cause the formation of corns, is brought to bear on the sensitive sole, an extravasation of blood occurs. In time when the cause remains active, this discoloration is evident in the substance of the insensitive sole and consists in a red or yellowish spot which varies in size—this is ordinarily termed dry corn.
In some cases where infection of this extravasation of blood and serum occurs, instead of desiccation and discoloration of the insensitive parts, there is, in time, manifested a circumscribed area of destruction of the insensitive sole and the abscess may, where no provision for drainage exists, burrow between sensitive and insensitive laminae and perforate the tissues at the coronet. If the suppurative material discharges readily by way of the sole, no disturbance of the heel or quarters occurs above the hoof.
Symptomatology.—A supporting-leg-lameness characterizes this condition; and this lameness in most instances varies in degree with the amount of distress which is occasioned by pressure upon the inflamed parts. By an examination of the sole after having removed all dirt, and exposed the horny sole to view, no difficulty is encountered in locating the cause of the trouble.
Treatment.—Before suppuration has taken place and in the cases where suppuration does not occur, the horse-shoer's method of paring out the diseased tissue affords a means of temporary relief; but unless frequently done, in many cases, lameness results within about three weeks after such treatment has been given. In other instances temporary relief is not to be gotten in this manner for any great length of time or until a more rational mode of treatment becomes necessary so that the subject may experience a cessation of the inconvenience or distress.
The general plan which meets with the approval of most practitioners consists in careful leveling of the foot and removing enough of the wall and sole at the quarters to make possible frog pressure by means of a bar shoe. With frog pressure, expansion of the heel follows in time, and permanent relief is obtainable in this manner. Thinning the wall of the quarter is advocated by many practitioners and is undoubtedly beneficial in chronic cases where marked contraction has taken place. The wall must be thinned with a rasp until it is readily flexible by compressing with the thumbs.
There are instances, however, where corns and contraction of the heel have existed so long that they do not yield to treatment. Such cases are found in old light-harness or saddle-horses that have been more or less lame for years and where there exists marked contraction of the heels, rough hoof walls, and hard and atrophied frogs.
Suppurating corns require surgical attention in the way of removal of the purulent necrotic mass and making provision for drainage. Dry dressings, such as equal parts of zinc sulphate and boric acid, may be employed to pack the cavity. After the infectious condition has been controlled, and the wound is dry, the same plan of treatment is indicated that is employed in the non-suppurating corn. Ample time is allowed, however, for the surgically invaded tissues to granulate and, if the subject is to be put in service, a leather pad, under which there has been packed oakum and tar, affords good protection.
Quittor.
This name is employed to designate an infectious inflammation of the lateral cartilage and adjoining structures. The disease is characterized by a slowly progressive necrosis and by a destruction of more or less of the cartilage and by the presence of fistulous tracts.
Etiology and Occurrence.—The disease is due to the introduction of pus producing organisms into the subcoronary region of the foot under conditions which favor the retention of such contagium and extension of infection into contiguous tissues.
Morbific material is introduced into the region of the lateral cartilage by means of calk wounds and other penetrant injuries of the foot. A sub-coronary abscess which, because of lack of proper care or because of virulency of the contagium or low vitality of the subject, is quite apt to result in cartilaginous affection and its perforation by necrosis follows.
Symptomatology.—Quittor is readily diagnosed on sight in many instances. Where there is dependable history or other evidence of the chronicity of an infectious inflammation of the kind, quittor is easily identified. If no positive evidence of the disease exists, by means of careful exploration of sinuses with the probe, one may distinguish between true cartilaginous quittor and superficial abscess formation that is often accompanied by hyperplasia.
Lameness depends upon the extent of the involvement as it affects the structures contiguous to the cartilage. A variable degree of lameness is manifested in different cases.
Treatment.—Two general plans of handling this disease are in vogue. One, the more popular method, consists in the injection of caustic solutions of various kinds into the fistulous openings with the object of causing sloughing of necrotic tissue and the stimulation of healthy granulation of such wounds. The other mode consists in either complete surgical removal of the cartilage or its remaining portions, or removal of the diseased parts of curettage.
When quittor has not extensively damaged the foot and the lateral cartilage is not partly ossified as it is in some old chronic cases, the complete removal of the lateral cartilage by means of the Bayer operation or a modification thereof is indicated. A complete description of the Bayer operation as well as Merillat's operation for this disease (the latter consisting in part, in the removal of diseased cartilage with the curette) are given in Volume three of Merillat's "Veterinary Surgical Operations."
Treatment by injection of caustic solutions has many advocates and because of the fact that, in many instances the condition is such that they are not desirable surgical cases and also because some animals may be put in service before treatment is completed, the injection method is popular.
The mode of treatment advocated by Joseph Hughes, M.R.C.V.S., constitutes a very successful manner of handling quittor and we can do no better than quote Dr. J.T. Seeley[33] on his manner of using this particular treatment.
Preparation.—First remove the shoe, have the foot pared very thin and balanced as nicely as possible. Moreover, all loose fragments of horn must be detached and all crevices cleaned thoroughly.
Next, have the leg brushed and hair clipped from the knee or hock to the foot and scrubbed with ethereal soap and warm water, after which the foot must be scrubbed in like manner. The foot is then placed in a bichlorid bath several hours daily, for from two to five days, depending upon whether or not soreness is shown. The bichlorid solution is 1 to 1,000 strength.
On removing the horse from the bath a liberal layer of gauze is soaked in 1 to 1,000 bichlorid solution and placed so as to cover the entire foot. On discontinuing the bath, cover the foot with gauze saturated with a 1 to 1,000 bichlorid solution. This is to be covered with absorbent cotton and a gauze bandage, and over all is placed an oil cloth or silk covering. This pack is kept moist with bichloride solution for forty-eight hours. The foot is then ready for injection.
Preparation of the Injection Fluids.—Have on hand a pint of a one per cent aqueous solution of formaldehyd made under cleanly conditions, even to a clean bottle and cork, and a clean container when ready to use the liquid. Prepare also a bichlorid of mercury solution as follows: Hydrarg. Chlor. Corros. 3IV; Acid Hydrochlor. 3Iss.; Aqua Bulliens, Oij. This should be thoroughly triturated, and then filtered into a clean bottle, when it is ready for use.
Injection.—The patient should be laid on a table, if one is available, or cast, and the foot securely fixed. Then, with an ordinary one-ounce hard rubber syringe, with a good plunger (tried first to note whether or not any fluid works around between the barrel and the plunger), introduce one syringe full of the formaldehyd solution, then thoroughly probe the quittor to determine the number of sinuses. This done, inject each sinus. If two sinuses open on the surface, close one with cotton while filling the other so that if there is a connection the solution will come in contact with all tissues involved. Irrigate with the full pint of formaldehyd solution first, then follow with six or eight ounces of the bichlorid solution. Never probe the foot nor allow it to be tampered with except in the manner prescribed.
After-Treatment.—Put on a pack saturated with a solution of bichlorid of mercury 1 to 1,000 and let it remain two days. Remove pack, and once daily afterwards wipe off with cotton the secretion which accumulates on the outside, and apply a dry dressing or healing oil composed of phenol, camphor gum and olive oil.
When Dangerous to Inject.—Never inject a quittor in the acute stage. Never inject a quittor if considerable lameness is present. On injecting a solution of formalin, hold cotton tightly around the nozzle of the syringe, when the plunger is down, then withdraw the syringe gently and note particularly if the fluid returns through the opening; if none returns cease operations at once, as it is dangerous to proceed farther, it indicates that the sinus is not well defined and the fluid retained will cause much trouble and often the death of the patient.
Experience has taught that, if extensive destructive changes of the foot exist, the Bayer operation is not indicated. In the country, where quittors are not so frequently met as in urban practice, the Merillat operation is preferable in all cases. However, the cost of the protracted period of idleness, which convalescent surgical patients require, renders the Hughes method more satisfactory in the hands of the general practitioner, especially in the city.
Nail Punctures.
Nail punctures, as herein considered, embrace all penetrant wounds of the solar surface of the horse's foot due to trampling upon street nails. This does not include accidental nail pricks occasioned in shoeing. In city practice, in some stables, these cases are of frequent occurrence; and, generally speaking, nail punctures are observed more frequently in urban horses than in animals that are kept in the country.
Occurrence and Method of Examination.—This condition, then, is a rather common cause of lameness and in no case, where cause of the claudication is not obvious, is the practitioner warranted in concluding his examination without careful search for the possible existence of nail puncture of the solar surface of the foot.
In occasional instances there co-exists an obvious cause for supporting-leg-lameness and an occult cause—a nail puncture. Where such complications are met, the practitioner is not necessarily guilty of neglect or carelessness when the nail puncture is not discovered at once, nevertheless, an examination is not complete until practically every possible cause of lameness has been located or excluded in any given case.
In a search for nail puncture it is necessary to expose to view every portion of the sole and frog in such manner that the existence of the smallest possible wound will be revealed. This necessitates removal of the shoe, if, after a preliminary examination, a puncture is not found, when there is good reason to suspect its presence. However, where it is readily possible to locate and care for a wound without removal of the shoe, allowing the shoe to remain materially facilitates retaining dressings in position and relieves the solar surface of contact with the ground. If extensive injury or infection exists, it is of course necessary to remove the shoe and leave it off. By removing a superficial portion of all of the sole and frog, thus carefully and completely exposing to view all parts of the solar surface of the foot, and with the aid of hoof-testers one is enabled to positively determine the existence of nail punctures. Because of the tendency of puncture wounds of the foot to close, and since the superficial portion of the solar structures are usually soiled, it is absolutely necessary to conduct examinations of this kind in a thorough manner.
Symtomatology.—Not all cases of nail puncture cause lameness during the course of the disturbance and in many instances no lameness is manifested for some time after the injury has been inflicted—not until infection has been the means of causing considerable inflammation of sensitive structures. Nevertheless, this lack of manifestation occurs only in cases where serious injury has not taken place and the degree of lameness is a constant and reliable indicator of the character and extent of nail punctures within twenty-four hours after injury has been inflicted.
The position assumed by the affected animal inconstantly varies with the location and nature of the injury and is not of particular importance in establishing a diagnosis. The subject may support some weight with the affected member and stand "base-wide" or "base-narrow," or no weight may be borne with the foot or the animal may point or keep the extremity in a state of volar flexion. In cases where extensive injury has been inflicted, and great pain exists, the foot is kept off the ground much of the time and it may be swung back and forth as in all painful affections of the extremity.
Nail punctures cause typical supporting-leg-lameness and in some cases certain peculiarities of locomotory impediment are worthy of notice. Punctures of the region of the heel, which directly affect or involve the deep tendon sheath, cause a type of lameness wherein pain is augmented, when dorsal flexion of the extremity occurs as well as when weight is borne. Wounds in the region of the toe of the hind feet sometimes cause the subject to carry the extremity considerably in advance of the point where it is planted and, just before placing the foot on the ground, it is carried backward a little way—ten or twelve inches.
However, diagnosis of nail puncture is based on the finding of the characteristic wound or resultant local changes.
Course and Prognosis.—The nature of the progress and the manner of termination of these cases are variable. If the coffin joint has been invaded, and a septic arthritis exists, the condition is at once grave. An open and infected tendon sheath, while not so serious, constitutes a condition which is distressing, and recovery is slow even under the most favorable conditions. Where a heavy, rigid and sharp nail enters the foot, in such manner that fracture of the third phalanx (os pedis) occurs, this complication makes for a protraction of the condition. Experience teaches that the natural course and termination in these cases are modified by the location and depth of the injury, virulency of the contagium and resistance of the subject to such infection.
Prevention.—In all horses which are kept at such work that exposure to nail punctures is frequent, a practical means of prevention of such injuries consists in the employment of heavy sole leather or suitable sheet metal to cover the sole of the foot and, at the same time, confine oakum and tar in contact with the solar surface to prevent the introduction of foreign material between the foot and such protecting appliances. Further, if drivers and owners could be impressed with the serious complications which so frequently attend wounds of this kind, undoubtedly many cases which are now lost, because of ignorance or neglect on the part of the teamsters or proprietors of horses, would be saved by prompt and rational treatment.
Treatment.—The treatment of this condition falls so largely within the dominion of surgery that we can give little more than an outline here.
In cases where there exists no evidence of open joint or open tendon sheath as judged by the site of the puncture and degree of lameness present (after having thoroughly cleansed the solar surface of the foot and enlarged the opening in the nonsensitive sole) a little phenol is introduced into the wound. In such cases, where it is possible for the antiseptic to contact every part of wound surface to the extreme depths of the puncture, infection is prevented when such treatment is promptly administered. This may be considered as first aid, or emergency care, and is indicated in all wounds of the foot whether the injury be serious or almost insignificant.
Subsequently one of two general courses may be pursued in the treatment of cases of nail puncture. One, by the employment of means to keep the wound patent and injection of suitable antiseptics, or agents that are more or less caustic in conjunction with strict observance of asepsis and wound protection. The other method consists in prompt establishment of drainage by surgical means and includes exploration and curettage.
The first method is better adapted to the use of the average general practitioner and he would do well to keep the opening in the nonsensitive structures patent. By introducing equal parts of tincture of iodin and glycerin daily, good results will follow in most instances. The wound is protected in unshod horses, either by completely bandaging the foot and retaining, in contact with the wound, cotton that is saturated with iodin and glycerin, or, if a minor injury exists, the moderately enlarged opening in the nonsensitive sole or frog, which has been moistened with the antiseptic, is packed with a very small quantity of cotton. A little practice in this mode of closing benign puncture wounds will enable the practitioner to successfully protect the sensitive parts in the treatment of such cases in unshod country horses.
When the condition progresses favorably the wound may be dressed every second day or twice weekly, and in the course of from two to six weeks recovery should be complete.
If the practitioner is somewhat proficient as a surgeon, and has at his command facilities for doing surgery, the second method is preferable in many cases. By using a local anesthetic on the plantar nerves and confining the subject on an operating table, restraint should be perfect. The solar surface of the foot is first thoroughly cleansed, the puncture wound is enlarged in the nonsensitive structures and the parts are then moistened with phenol or other suitable antiseptics. By means of a small probe the puncture is explored and, depending on the character of the wound and the structures involved, surgical intervention is varied to suit the case. If necessary, all of the insensitive frog is removed, and in wounds affecting the region of the heel the tissues may be incised from the puncture outward dividing all of the tissues outward and backward to the surface. A suitable surgical dressing is then applied.
If, on the other hand, the puncture extends into the navicular bursa, the radical operation is perhaps indicated, though not until one is sure that infection of the bursa and serious consequences are to follow if this operation is not performed. Detailed description of the technic of this operation belongs to the realm of surgery and a good discussion of it is to be found in William's work on veterinary surgical and obstetrical operations.
One may summarize the discussion of treatment of nail puncture by saying that emergency care as herein described is of first consideration. In every case an immunizing dose of anti-tetanic serum should be given. Subsequently, the method employed must suit the character of the wound, existing facilities for handling the subject and the skill and aptitude of the practitioner.
FOOTNOTES:
[Footnote 5: Manual of Veterinary Physiology, by Major-General F. Smith, page 590.]
[Footnote 6: Manual of Veterinary Physiology by Major-General F. Smith, page 589.]
[Footnote 7: Regional Veterinary Surgery and Operative Technique, Jno. A.W. Dollar, M.R.C.V.S., F.R.S.E., M.R.I., page 765.]
[Footnote 8: Dr. Roscoe R. Bell in the Proceedings, N.Y. State Veterinary Medical Society, 1899.]
[Footnote 9: American Veterinary Review, Vol. 35, P. 456.]
[Footnote 10: "Radial Paralysis and Its Treatment by Mechanical Fixation of Knee and Ankle," Geo. H. Berns, D.V.S. Proceedings of the American Veterinary Medical Association, 1912, p. 219.]
[Footnote 11: As quoted by Berns, in Radial Paralysis, etc., Proceedings of the A.V.M.A., 1912.]
[Footnote 12: Veterinary Surgical Operations, by L.A. Merillat, V.S., p. 507.]
[Footnote 13: A paper presented before the Illinois Veterinary Medical Assn. by Dr. H. Thompson of Paxton, Ill., American Veterinary Review, Vol. 15, p. 134.]
[Footnote 14: "Fractures in Foals," by Dr. Wilfred Walters, M.R.C.V.S., American Journal of Veterinary Medicine, Vol. 8, p. 669.]
[Footnote 15: American Veterinary Review, Vol. 26, p. 1068.]
[Footnote 16: Fractures, by H. Thompson, Paxton, Ill., American Veterinary Review, Vol. 15, p. 134.]
[Footnote 17: Veterinary Surgical Operations, by L.A. Merillat, Vol. 3, p. 198.]
[Footnote 18: Wilfred Walters, American Journal of Veterinary Medicine, Vol. 8, p. 606.]
[Footnote 19: J.N. Frost, assistant professor of Surgery, Veterinary Dept., Cornell University, in "Wound Treatment," page 159.]
[Footnote 20: Open Joints and Their Treatment in my practice, by J.V. Lacroix, American Journal of Veterinary Medicine, Vol. 5, page 203.]
[Footnote 21: Regional Veterinary Surgery Moeller—Dollar, page 605.]
[Footnote 22: Extract from Receuil de Medecine Veterinaire in Ameircan Veterinary Review, Vol. 23, p. 893.]
[Footnote 23: Fracture of All the Sesamoid Bones, by R.F. Frost, M.R.C.V.S., A.V.D., Rangoon, Burmah, in American Veterinary Review, Vol. 5, p. 362.]
[Footnote 24: The Anatomy of the Domestic Animal, by Septimus Sisson, S.B., V.S.]
[Footnote 25: Traite De Therapeutique Chirurgicale Des Animaux Domestique, par P.J. Cadiot et J. Almy, Tome Second, page 547.]
[Footnote 26: Anatomie Regionale Des Animaux Domestique, page 695.]
[Footnote 27: Manual of Veterinary Physiology, by Major-General F. Smith, C.B., C.M.G., page 678.]
[Footnote 28: Moeller's Regional Veterinary Surgery, by Dollar, page 630.]
[Footnote 29: Edinburgh Veterinary Review, Vol. VI, page 616.]
[Footnote 30: Equine Laminitis or Pododermatitis, by R.C. Moore, D.V.S., American Journal of Veterinary Medicine, Vol. XI, page 284.]
[Footnote 31: American Journal of Veterinary Medicine, Vol. XI, page 318.]
[Footnote 32: The Shoeing of a Dropped Sole Foot by Dr. David W. Cochran, New York City, The Horse Shoers Journal, March, 1915.]
[Footnote 33: Quittor and Its Treatment by the Hughes Method, J.T. Seeley, M.D.C., Seattle, Washington, Chicago Veterinary College Quarterly Bulletin, Vol. 9, page 27.]
SECTION IV.
LAMENESS IN THE HIND LEG.
Anatomo-Physiological Consideration of the Pelvic Limbs.
The pelvic bones as a whole constitute the analogue of the scapulae with respect to their function as a part of the mechanism of locomotive and supportive apparatus of the horse. The manner of attachment or connection between the ilia and the trunk is materially different from that of the scapulae, however, and the angles as formed by the long axes of the ilia in relation to the spinal column are maintained by two functionally antagonistic structures—the sacrosciatic ligaments, and the abdominal muscles by means of the prepubian tendon. The sacro-iliac articulations are such that a very limited amount of movement is possible; free movement, however, is unnecessary because of the enarthrodial (ball and socket) femeropelvic joint.
The various muscles which exert their effect upon the pelvis in changing their relationship between the long axes of the ilia and spinal column, are concerned but little more in propulsion and weight bearing than are the pectoral muscles. A general treatise on the subject of lameness does not properly include such structures any more than it does the various affections of the dorsal, lumbar and sacral vertebrae or inflammation of the abdominal parietes. Involvement of such parts cause manifestations of lameness but the matter of establishing a diagnosis is difficult in many instances and in some cases impossible.
The femeropelvic articulation is formed by the hemispherical head of the femur and the acetabulum; the latter constituting a cotyloid cavity which is deepened by the cotyloid ligament.
The round ligament (ligamentum teres) is the principal binding structure of the hip joint and it arises in a notch in the head of the femur and is attached in the subpubic groove close to the acetabular notch. Another ligament, peculiar to Equidae—the accessory (pubiofemoral)—is attached to the head of the femur near the round ligament and passes through the cotyloid notch and along the under side of the pubis. It is inserted or blends with the prepubic tendon. This ligament prevents extreme abduction of the leg. The joint capsule encompasses the articulation and is attached to the brim of the acetabulum and the edge of the head of the femur.
The stifle joint is analagous to the knee joint of man and is to be considered an atypical ginglymus (hinge) articulation formed by the femur, tibia and patella. The ligaments are femerotibial, femeropatellar and capsular.
In addition to the usual provision for articulation of bones there are situated cartilaginous menisci between the condyles of the femur and the head of the tibia. These discs surround the tibial spine and are otherwise shaped to fit perfectly between the articular portions of the femur and tibia.
Collateral ligaments (internal and external lateral) pass from the distal end of the femur to the proximal portion of the tibia. The mesial (internal) arises from the internal condyle of the femur and is attached to a rough area below the margin of the medial (internal) condyle of the tibia. The lateral (external), shorter and thicker, arises from the depression on the lateral epicondyle and inserts to the head of the fibula.
The crucial or interosseus, anterior and posterior, are situated between the femur and tibia, and according to Smith,[34] the crucial ligaments are necessary to properly join the two bones, because of the character of the structure of the articular ends of the femur and tibia.
The femeropatella ligaments are two thin bands which reinforce the capsular ligament. They arise from the lateral aspects of the femur, just above the condyles and are inserted to the corresponding surfaces of the patella.
The patellar ligaments are three strong bands which arise from the antero-inferior surface of the patella, and are inserted to the anterior aspect of the tuberosity of the tibia.
Taken as a whole, the tarsal bones, interarticulating and articulating with the tibia and metatarsal bones form the hock joint and this articulation is analagous to the carpus. As with the carpus, there is less movement in the inferior portion of the joint than in the superior part of the articulation. The chief articulating parts are the tibia with the tibial tarsal bone (astragulus).
The capsular ligament is attached around the margin of the articular surfaces of the tibia, to the tarsal bones, the collateral ligaments (internal and external lateral) and to the metatarsus.
The common ligaments of the tarsal joint are the collateral, the plantar (calcaneo-metatarsal and c. cuboid) and dorsal ligaments (oblique).
The medial (internal lateral) ligament serves to join the medial (internal) tibial malleolus with tibial tarsal (astragalus) and other tarsal bones.
The lateral (external lateral) ligament is inserted to the lateral (external) tibial malleolus and its distal portions are attached to the tibial tarsal (astragalus), fibular tarsal (calcaneum) bone, fourth tarsal (cuboid) and metatarsus bones.
The plantar ligament (calcaneo-cuboid) is a strong flat band which is attached to the plantar surface of the fibular and fourth tarsal bones (calcaneum and cuboid) and the head of the lateral metatarsal (external small) bone.
The dorsal (oblique) ligament is attached above to the distal tuberosity on the inner side of the tibia. It is inserted below to the central (cuneiform magnum) and third (c. medium) tarsal bones, to the proximal ends of the large and outer small metatarsal bones.
The tarsus is a true hinge joint and because of the great strain which it sustains, is subject to frequent injury. About seventy-five percent of cases of lameness affecting the hind leg may be said to arise from disease of the hock.
As members of locomotion the legs receive strains of two kinds: those of concussion and weight-bearing and strains of propulsion; the latter are the greater. In the horse as a work animal, the hind legs are probably subjected to greater strains than are the front but the manner of construction of the various parts of the pelvic limbs with the possible exception (according to some authorities) of the tibial tarsal joint, offsets this condition.
The femur may be considered analagous to the humerus in that it bears a similar relationship to the ilium, that exist between the humerus and scapula. Further flexion during repose is prevented chiefly by the glutens medius (maximus) muscle and its tendons. The larger tendon inserts to the summit of the trochanter major of the femur and corresponds to the biceps brachii in the action of the latter on the scapulohumeral joint, except that the gluteus medius, in attaching to the femoral trochanter, exerts its effect as a lever of the first class. Because of the relationship between the long axes of the femur and iliac shaft it is evident that the angle formed by these two bones is maintained chiefly by the gluteus muscles during weight bearing. Contraction of muscular fibers of the gluteus medius causes extension of the femur and muscular strain is prevented to a great degree by the inelastic portion of this muscle. The chief physiological antagonistics of the glutei are the quadriceps femoris and tensor fascia lata.
While the leg is supporting weight the stifle joint is fixed in position mainly by the quadriceps femoris group of muscles which are attached to the patella. Tendinous fibres intersect this muscular mass and relieve muscular strain during weight bearing. Because of the manner in which the patella functionates with the trochlea of the femur, comparatively little energy is required to prevent further flexion of the stifle joint. The patella, according to Strangeways, may be considered a sesamoid bone.
The quadriceps group of muscles is assisted by the anterior digital extensor (extensor pedis) peroneus tertius and tibialis anticus (flexor metatarsi) muscles. The latter pair (flexor metatarsi, muscular and tendinous portions, because of their attachment to the external condyle of the femur and to the metatarsal bone) are enabled to automatically flex the tarsal joint when the stifle is flexed.
The hock is kept fixed in position by the gastrocnemius and the superficial digital flexor (perforatus). The latter structure, which is chiefly tendinous, originates in the supracondyloid fossa of the femur and has an insertion to the summit of the fibular tarsal (calcis) bone. It relieves the gastrocnemius of muscular strain during weight bearing.
Smith[35] styles the function of the stifle and hock joints a reciprocating action, and we quote from this authority the following:
From what has been said, it is evident that flexion and extension of stifle and hock are identical in their action. When the stifle is extended, the hock is automatically extended, nor can it under any circumstances flex without the previous flexion of the stifle. There is no parallel to this in the body. The two joints, though far apart, act as one, and they are locked by the drawing up of the patella, and in no other way. The so-called dislocation of the stifle in the horse is a misnomer. That the patella is capable of being dislocated is beyond doubt, but the ordinary condition described under that term, when the stifle and hock are rigid while the foot is turned back with its wall on the ground, is nothing more than spasm of the muscles which keeps the patella drawn up. The moment they relax the previously immovable limb and useless foot have their function restored as if by magic, but are immediately thrown out of gear in the course of a few minutes as a recurrence of the tetanus of the petallar muscle takes place. The fascia of the thigh, like that of the arm, is a most potent factor in giving assistance to the constant strain imposed on the muscles of the limbs during standing.
Below the hock the hind limb is arranged like that of the fore, the deep flexor (perforans) receiving its additional support from the "check ligament," as in the fore leg.
The natural attitude of standing adopted by the horse is to rest on three legs—one hind and two fore. If he is alert, he stands on all four limbs; but if standing in the ordinary manner, he always rests on one hind leg. He does not remain long in this position without changing to the other. Hour by hour he stands, shifting his weight at intervals from one to the other hind leg, and resting its fellow by flexing the hock and standing on the toe. He never spares his fore-limbs in this manner in a state of health, but always stands squarely on them.
Hip Lameness.
Fortunately, because of the heavy musculature which goes to form a part of the locomotive apparatus of the rear extremity, hip lameness is comparatively rare. While the term is in itself ambiguous and signifies nothing more definite than does "shoulder lameness," yet diagnosis of almost any condition that may be classed under the head of "hip lameness" is not easy except in cases where the cause is obvious, as in wounds of the musculature and certain fractures. To the complexity which the gait of the quadruped contributes, because of its being four-legged, there is added the complicated manner of articulation of the bones of the hind leg. This involves the hip in the manner of diagnostic problems and because of the inaccessibility of certain parts, owing to the bulk of the musculature of these parts, diagnosis of some hip ailments becomes an intricate problem. Consequently, in some instances, before one may arrive at definite and enlightening conclusions, repeated examinations are necessary as well as a knowledge of reliable history and recorded observations of the subject over a considerable period.
Rheumatic affections, when present, usually cause recurrent attacks of lameness; myalgia, due to subsurface injury occasioned by contusion, generally produces an ephemeral disturbance; and while these are examples of cases where occult causes are active, they are by no means unprecedented. In cases where the cause of lameness is not definitely located, and when by the process of exclusion one is enabled to decide that the seat of trouble is in the hip, a tentative diagnosis of hip lameness is always appropriate.
In one instance a Shetland pony evinced a peculiar form of intermittent lameness which affected the left hip, and repeated examinations did not disclose the cause of the trouble. After about a year there was established spontaneously an opening through the integument overlying the region of the attachment of the psoas major (magnus), through which pus discharged. With the occurrence of this fistula, lameness almost entirely disappeared, but the emission of a small amount of pus persisted for more than a year. The subject was not observed thereafter and the outcome in this case is not a matter of record. Whether there existed a psoic phlegmon due to metastatic infection or necrosis of a part of a lumber or dorsal vertebra is a matter for speculation. Thus the presence of some anomalous conditions which affect the pelvic region and cause lameness may be discovered, yet both in hip and shoulder regions causes may not be definitely located by means of practical methods of examination.
Injuries of all kinds are the more frequent causes of hip lameness. In such cases, lameness may result directly and resolution be prompt, or the claudication become aggravated in time, due to muscular atrophy or degenerative changes affecting the hip joint or nerves. Rheumatism or metastatic infection may be the cause of hip lameness as well as affections of the pelvic bones, lumbar and sacral vertebrae. Hip lameness may also be provoked by melanotic or other tumors.
In the diagnosis of hip lameness, one is guided in a general way by the character of the impediment manifested. Swinging-leg lameness is often present and the impediment is more accentuated when the animal is caused to step backward. In many cases lameness is mixed, being about equally noticeable during weight bearing and while the member is being swung. By exclusion of causes which might affect other parts; one may definitely locate the cause of the trouble or determine that a certain region is affected.
The sudden manifestation of lameness is indicative of injury; thermic disturbances may signalize metastatic infection; history, if dependable, is always helpful. Repeated observations, taking into account the course which the affection assumes during a period of a few days, often serve to afford a means of establishing a diagnosis in baffling cases.
Fractures of the Pelvic Bones.
The os innominatum may be so fractured that the pelvic girdle is broken, as in fracture of the iliac shaft, or in a manner that the girdling continuity of the innominate bones is not interrupted. It naturally follows that greater injury is done when the pelvic girdle is broken than when it is not, except in cases where the acetabulum is involved and its brim not completely divided.
Etiology and Occurrence.—Pelvic fractures are usually caused by falls or other manner of contusion. Cases are reported where it would seem that fracture of the iliac angle resulted from muscular contraction, but it is certain that most fractures of this kind are due to collisions with door jambs or similar injuries. In old horses especially, fracture of pelvic bones occurs frequently. This form of injury is of more frequent occurrence in animals of all ages that work on paved streets. The country horse is not subjected to the uncertain footing of the slippery pavement, nor to injuries which compare with those caused by contusions sustained in falling upon asphalt or cobble-stones.
Symptomatology.—While in many cases of pelvic fracture lameness or abnormal decumbency are the salient manifestations, yet the pathognomic symptoms are crepitation or palpable evidence which may be obtained by rectal or vaginal examination. In fractures of the angle of the ilium and the ischial tuberosity, perceptible evidence always exists.
In cases where fracture of some portion of the pelvic girdle is suspected and the subject is able to walk, crepitation is sought by placing one hand on an external angle of the ilium and the other on the ischial tuberosity and the animal is then made to walk. Or, by placing the hands as just directed, an assistant may grasp the horse's tail and by alternately exerting traction on the tail and pushing against the hip in such manner that weight is shifted from one leg to the other, crepitation may be detected.
Fracture of the pubis near its symphysis constitutes a grave injury, as there is danger of the bladder becoming caught in the fissure and perforation of its wall may result. Such a case is reported by Bauman[36] wherein a three-year-old gelding bore the history of having been lame for ten days. Upon rectal examination the bladder was found to be hard and tumor-like and about the size of a baseball. The body of the ischium in this case was fractured and a rent in the bladder was caused by a sharp projecting piece of bone. Autopsy revealed, in addition to the fracture and rent of the bladder wall, a large quantity of urine in the peritoneal cavity.
In other instances hemorrhage caused death and not infrequently infection was responsible for a fatal issue. Moller,[37] quoting Nocard, describes a case where fracture occurred through the region of the foramen ovale and paralysis of the obturator nerve followed.
Fractures which include the acetabular bones cause great pain. This is manifested by marked lameness, both during weight bearing and when the member is swung. Such cases terminate unfavorably—complete recovery is impossible.
Where small portions of the angle of the ilium are broken, and the skin is left intact, there exists the least troublesome class of pelvic fracture. If large portions of the ilium are fractured, considerable disturbance results. There eventually occurs more or less displacement in such cases, if such displacement does not take place at the time of injury. The same may be said of fracture of the tuber ischii, but when these bones are fractured a more serious condition results.
Treatment.—When a case is found to be uncomplicated, that is, if the fracture is such that recovery seems possible and after having determined that treatment may be practicable, the first consideration is that of confining the subject in suitable slings. In many cases of pelvic fracture, the affected animal will need to be kept in slings from six weeks to three months, and it becomes a difficult problem to minimize the distress during this long period of confinement in the peculiar manner required for favorable outcome.
The pattern of sling employed should be the best that is obtainable and the matter of its adjustment is quite important lest unnecessary chafing or even necrosis of skin result. Frequent readjustment may be necessary, and time is well spent in this manner since this contributes materially toward a favorable termination by encouraging the subject to remain quiet so that coaptation of the broken bones may be maintained. Aside from slings, mechanical appliances that are helpful in the treatment of these cases are not yet in use.
A regimen that is nutritive and at the same time laxative is essential and in some cases cathartics and enemata are necessary. Also, during the first few days, if there is retention of urine, catheterization is imperative. In a word, the handling of such cases consists largely in keeping the subject inactive, as comfortable as possible, and giving attention to suitable diet.
Simple fracture of the external iliac angle needs no particular attention, except that the subject is kept quiet until lameness subsides. In all cases where much of the bone is broken, the animal is blemished, but interference with function does not follow. If infection results because of a compound fracture, loose pieces of bone must be removed surgically and drainage provided for.
In fracture of the ischial tuberosity, infection is more apt to result than in like injury of the ilium, and greater displacement of bone occurs. This displacement, due to contraction of the attached muscles, is in some instances a contributing cause to the infection which often follows in these cases. In females where the body of the ischium is fractured, lacerations of the vagina may be present, and this constitutes a serious complication which usually terminates fatally.
After-care in fracture of the pelvic girdle consists principally in allowing a protracted period of rest before subjects are put to work.
Fractures of the Femur.
Etiology and Occurrence.—This is a comparatively rare injury in the horse because of the protection afforded the femur by the heavy musculature. Fragilitas of the bone probably exists in many cases when fracture of its diaphysis occurs. It is generally conceded that the neck of the femur is rarely broken because of a lack of constriction in this part, but fracture of the trochanters has been recorded rather frequently. However, Lienaux and Zwanenpoete[38] state that fracture of the neck of the femur is of frequent occurrence in Belgian colts. Tapley[39] reports in the Veterinary Journal (English) fracture of the head and internal trochanter of the femur and patellar luxation occurring simultaneously affecting a mule. In this case the mule was found decumbent on a concrete floor. After three weeks, the subject was destroyed and autopsy revealed rupture of the left pubiofemoral ligament, tearing with it a portion of the articular surface of the femur. The internal trochanter was also fractured in four small pieces. In this case it is fair to suppose that the mule in trying to regain footing on a slippery floor violently abducted the legs and fracture resulted. It is possible also that a temporary luxation of the patella took place first and caused the animal to struggle in such manner that fracture followed.
Symptomatology.—According to Cadiot and Almy,[40] "regardless of the location of femoral fractures, the subject is usually intensely lame, the animal frequently walking on three legs—fractures of the diaphysis are characterized by an abnormal mobility."
As a rule, crepitation is to be recognized in fractures of the shaft of the bone, by passively moving the leg to and from the medial plane (adduction and abduction).
Fracture of the trochanter major is signalized by local swelling and evidence of pain; the forward stride is shortened because this movement tenses the tendon of the gluteus major (maximus) which is attached principally to the trochanter.
Treatment.—Reduction of femoral fracture in the horse is practically impossible, and retaining the broken bones in coaptation is not possible by means of mechanical appliances. Consequently, prognosis is unfavorable in fracture of the body of the femur. When union of bone occurs, there results shortening of the leg and animals are rendered permanently lame. If the immediate region of the head of the bone is involved as well as in case of fracture of the condyles, an incurable arthritis ensues.
Where the trochanters are broken, chronic lameness and muscular atrophy is the result. Therefore, it is evident that, because of the manner of function of the femur, the leverage afforded by its great trochanter and its heavy muscular attachments, fractures of this bone in the horse do not terminate favorably.
Luxation of the Femur.
Etiology and Occurrence.—Uncomplicated femoral luxation is of less frequent occurrence in the horse than in the other domestic animals. The deep cotyloid cavity renders disarticulation difficult and luxation does not often take place. Complications that usually occur are rupture of the round (coxofemoral) ligament or fracture of the neck of the femur. Falls or violent strains are necessary to produce this luxation. Goubaux is quoted by Cadiot and Almy[41] as having observed the head of the femur in an instance wherein luxation had long existed. In this case autopsy revealed the fact that the inner portion (two-thirds) of the head of the femur had completely disappeared.
Luxation of the femur is observed in old emaciated animals that are worked on slippery pavements. Occasionally, evidence of chronic luxation of the femur is observed in the anatomical laboratory. The chronicity of the condition is obvious when one notes the well formed articulation which Nature provides for the head of the femur, where fracture or other serious complications are not present.
Symptomatology.—In every case there must exist either restriction of movement or an evident abnormal position of the leg, or both conditions may exist at once. Also, the leg may be markedly shortened. Manifestation of this affection varies, depending upon the character of the luxation (position of the head of the humerus with relation to the acetabulum). Lusk[42] cites a case of a mule which had suffered femoral luxation. The animal was destroyed and on autopsy the head of the femur found to be contained within a false articular cavity situated about four inches above the acetabulum. In Dr. Lusk's case as he states it, the following symptoms were presented: "Limb shortened and fixed in a position of adduction. While standing the affected limb hung directly across and in front of the opposite one; upper trochanter very prominent; skin over hip joint very tense. The mobility of the limb was very limited, especially in the forward direction."
Being very prominent when there is an upward luxation and less perceptible in downward displacement, the location of the trochanter major is an indicator of the character of the luxation with respect to the position of the head of the femur. This variation of position causes abnormal tenseness or looseness of the skin over the region of the trochanter major. Rectal examination is of aid in locating the head of the humerus.
Treatment.—When it is evident that a subject should be given treatment and not destroyed, the animal must be cast and completely anesthetized. With complete relaxation thus secured by rotation of the limb, using the hip joint region as a pivot, reduction may be effected. Traction is exerted in the same direction from the acetabulum that the head of the femur is situated and by pressing over the joint, the displaced bone may be returned in position. If luxation is downward, traction on the extremity will tend to dislodge the head of the femur from the inferior acetabular margin making reduction possible.
The same general plan which is ordinarily employed in correcting luxation is indicated here, but because of the heavy musculature of the hip, complete anesthesia is imperative in all such manipulations.
Gluteal Tendo-Synovitis.
The glutens medius (g. maximus) muscle is inserted chiefly by means of two tendons; one to the summit of the trochanter major of the femur and the other passing over the anterior part of the convexity of the trochanter, and being attached to the crest below it. The trochanter is covered with cartilage, and a bursa (the trochanteric) is interposed between the tendon and the cartilage.
Etiology and Occurrence.—This affection is probably caused in most instances by direct injury to the parts, such as may be occasioned by being kicked, falling on pavement, or being struck by the body of a heavy wagon. Strains in pulling or in slipping are undoubtedly causative factors and in draft horses such strains may result in involvement of this synovial apparatus.
Symptomatology.—If pain be severe and inflammation acute, weight may not be borne with the affected member. There is some local manifestation of the condition in acute cases. Swelling of the tissues contiguous to the bursa is present and pain is evinced upon manipulation of the parts. A characteristic gait marks inflammation of the trochanteric bursa, and as Gunther has put it, the subject generally moves or trots as does the dog—the sound member being carried in advance of the affected one and the forward stride of the diseased leg is shortened. In some chronic cases crepitation is discernible by holding the hand on the trochanter while the subject walks.
Treatment.—In the first stages of an acute affection absolute quiet must be enforced; local antiphlogistic applications are beneficial. Later, vesication of a liberal area surrounding the trochanter major is indicated. Where the condition has become chronic in horses that are to be kept at heavy draft work there is little chance for complete recovery. And, naturally, one is not to expect resolution in cases where there exist erosion and ossification of cartilage—where crepitation is discernible.
Paralysis of the Hind Leg.
Aside from paraplegic conditions due to disease of the cord or the lumbosacral plexus, and monoplegic affections resultant from disturbances of this plexus, paralysis of certain nerves are occasionally encountered.
Anatomy.—The lumbosacral plexus results substantially from the union of the ventral branches of the last three lumbar and the first two sacral nerves, but it derives a small root from the third lumbar nerve also. The anterior part of the plexus lies in front of the internal iliac artery, between the lumbar transverse processes and the psoas minor. It supplies branches to the iliopsoas[43] (designated by Girard, the iliacomuscular nerves). The posterior part lies partly upon and partly in the texture of the sacrosciatic ligament. From the plexus are derived the nerves of the pelvic limb (Sisson).
Paralysis of the Femoral (Crural) Nerve.
Anatomy.—The femoral nerve (crural) is derived chiefly from the fourth and fifth lumbar nerves. It runs ventrally and backward, at first between the psoas major and minor, then crosses the deep face of the tendon of the latter and descends under cover of the sartorious over the terminal part of the iliopsoas. It innervates the psoas major (magnus), psoas minor (parvus), sartorious, rectus femoris, vastus lateralis (interims). Branches supply the stifle and the adductor and pectineus muscles. |
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