Diseased Conditions of Joints
It will not be possible to intelligently describe the disorders coming under this head, unless there is a fairly clear idea of the structure of joints. A joint is a union, by means of ligaments, of two or more bones the opposing surfaces of which, so shaped as to be perfectly fitted into one another, are covered by cartilage and enclosed within a capsular ligament, forming a closed cavity which is lined throughout by a delicate membrane that, from its function, which is the secretor of the joint oil or synovia, is called the synovial membrane. Any one of these four tissues may be injured and become inflamed, but their liability to inflammation is in direct proportion to the amount of blood that they naturally contain, and that is in the following order: synovial membrane, bone, ligament, and cartilage.
The Causes which operate to produce diseases of the joints are very various; they may be local, as from blows, strains, and wounds; constitutional, when certain conditions which modify the vital processes in various other tissues of the body, but which are especially prone to locate in the joints, are met with, as in rheumatism, tuberculosis, etc.; or there may be a modification of one by the other, as, when a predisposition to disease of the joints is hereditary, a slight injury will induce a certain grave disorder which, in an animal without such taint, would be of no great consequence.
Bog Spavin is a soft, fluctuating swelling situated upon the inside front of the hock joint.
Causes. A chronic synovitis, which has been due to overwork of the limb or to some slight injury of it, as strain, twist, etc., as a result of which a large amount of synovial fluid has been poured out into the cavity of the capsular ligament, so creating, a dropsy of the joint, which has little, if any, tendency to become absorbed and disappear.
Symptoms. There may be, at first, a slight lameness which, when present, is due to the cause of the synovitis; this soon passes away, with rest, and there is left no more than the swelling described. This swelling usually remains of about the same size as at first shown, throughout life; occasionally it may be induced to disappear permanently, by treatment at other times it rarely happens that it
continues to grow until it reaches an immense size, in spite of all treatment, but this is usually in horses of lowered general vitality. When bog spavin is present, without lameness, it is a blemish, not an unsoundness, because, of itself, it is not a cause of lameness and, when of moderate size, does not interfere with the animal's work.
Treatment, as has already been intimated, is not often followed by the permanent disappearance of the enlargement. When it is first shown it may be painted with pure tincture of iodine once a day until it becomes sore; or blistered with the ointment of red iodide of mercury, two drams to the ounce of lard, applied as recommended for splint. The animal must not be allowed exercise during this treatment, under which the swelling is often removed; but it will nearly always return as soon as the horse is again put to work.
Thoroughpin. This name is given to a dropsical swelling, similar to that of bog spavin, with which it is often associated, situated just above the point of the hock, under the large tendon which comes down the back of the leg and passes over the point of the hock.
Causes. It comes as the result of a low form of inflammation of a synovial membrane there situated, the natural secretion of which is for the purpose of lubricating the gliding of the tendon in its sheath, at the part. The inflammation results from overwork of the tendon. It rarely causes lameness, excepting that which may be due to some little strain of the tendon, which, when present, passes off after a few days' rest, leaving a dropsical swelling which extends from side to side of the leg and is of larger or smaller size. A thoroughpin is not an unsoundness, unless the animal is going lame from it; which will be, if at all, when it first makes its appearance, and then the lameness is due to injury of the tendon.
Treatment will be the same as for bog spavin; with the same outlook as to permanent loss of the enlargement.
Capped Hock is a serous swelling of larger or smaller size situated directly upon the point of the hock, under the skin, which is very thick at the part. It is seen in cattle as well as horses.
Causes. It is the result of a blow, or more or less constant pressure upon the part. Horses that kick the sides of the stall are very apt to have it, as well as those that meet with accidents as a result of which the parts are injured. In cattle particularly, and rarely in horses, from lying upon a hard floor in such a position as to press the points of the hock upon it.
I Symptoms. There is a larger or smaller swelling, which, when it first comes, evidently contains fluid, is hot, and tender to the touch; there may or may not be lameness, depending entirely upon' the importance of the injury that has caused the enlargement.
Treatment. Prevent any repetition of the cause by padding the sides of the stalls, ff necessary. If the injury be recent and the part hot, slip an old overall leg up over the leg of the animal, tying it lightly around the limb just below and above the joint, thus leaving a sort of pocket around the joint. Fill this pocket with old sponge, cotton waste, or similar material, and keep it constantly wet with ice water until all heat and tenderness have passed off. If any enlargement remains, blister with the ointment of red iodide of mercury, as directed for splint, or, if preferred, paint the part daily with pure tincture of iodine until it becomes sore, then after a few days paint again, as long as necessary. The process of removing the enlargement, if it becomes at all chronic, is a slow one and not always entirely successful. The horse can be used during treatment, but great care must be taken to prevent any addition to the cause. It is not an unsoundness.
Curb. By this term is meant a hard swelling which appears at a point some three or four inches below the point of the hock, directly upon the back of the leg.
Cause. It is a strain of a ligament (caleaneo cuboid) which serves to bind the lower extremity of "os calcis" to other small bones of the hock joint. The cause of the strain is anything which tends to pull the point of the hock too strongly forward , as rearing, pulling heavy loads up hill, slipping, as in backing, with the hind legs well under the body, jumping over high objects, etc.
Symptoms. Upon examining the hind leg in profile it will be seen that, at the point named, there is an outward bulging varying in size from a hard, small nodule to a large, diffuse swelling, which may possibly, if the strain be a very recent one, be somewhat puffy, hot, and tender to the touch. If lameness be present, which depends rather upon the age of the curb than its size, it is characterized by difficulty in straightening the leg backward.
Treatment. Rest the horse, put on a shoe having no toe calk, and with heel calks about one and one quarter inches long, measuring from the foot surface of the shoe. When the injury is recent, or the swelling at all puffy and hot, it should be cooled as recommended for capped hock. After the inflammation has been thus removed the parts may be either blistered with the red iodide of mercury, as in splint, or fired; which operation will necessitate the services of a veterinarian. In some of the less important cases, or if the horse can be spared from work for some time, the blister will give good results. In very severe curb deep line firing is the only measure to be thoroughly relied upon. When put to work these recovered horses should be shod with fairly high heel calks, without any toe, for some little time.
If the injury to the hock be entirely comprehended in the curb, there is no doubt that the animal may be restored to soundness, so far as lameness goes, although the enlargement will, in all likeehood, remain. Older horses, those in which the bones have become thoroughly hardened, permanently recover much more quickly than do those under five years of age; among which there is a strong tendency to recurrence of the lameness, upon work, until the bones have age enough to harden them, that is, until they are seven years old. An old, hard curb, if the horse is not going lame, is a bad blemish, but not an unsoundness.
Bone Spavin is a disease of the small bones of the hock, through which a growth of new bony material, of larger or smaller size, after the nature of a splint, is deposited on the face of the joint, on its inner side, a little more than half way down between the hinge of the joint and the head of the cannon bone, which last may also be involved. The term refers to the enlargement only. When a horse is lame in this joint, and no bony enlargement is discoverable, he is said to be suffering from hock joint lameness. Some horses show a bony enlargement at this point in one or both legs, and no lameness exists. Such animals are said to have coarse hocks, and while one is always expecting that such an animal will commence to go lame at almost any time, many of them go through a life of work without ever showing lameness or limited action there.
Causes are predisposing and exciting. A predisposition to spavin may be hereditary or due to some peculiarity in the conformation of the leg, or joint, as in a " sickle hocked " horse, etc.; there is no doubt as to the hereditary tendency
The exciting causes are anything that may set up an inflammation of the synovial membrane, as strains or local injuries; or which may give rise to disease of the bones or its covering, the periosteum, as concussion, that is, too much fast work at either galloping or running, or anything that overworks the joint.
Symptoms. There is a hard enlargement upon the seat of spavin, which may be so large as to be easily seen from quite a little distance, when standing directly behind the horse, or so small as to need the most careful examination by an expert for its detection. The lameness is always shown when the unexercised horse begins to trot, and is somewhat peculiar in that it generally passes entirely away after the animal has been driven a distance varying from a few rods to a mile or two. In some instances the lameness is not lost, or it may even be increased, by exercise; this is when the cartilages of the small bones, the action of which is simply to glide upon one another, have become diseased, allowing their sore surfaces to rub together. The method of using the limb is peculiar in that the spavined horse invariably starts off and goes upon his toe, so long as the lameness lasts; and if the shoe of one of these animals is examined it will be seen that its toe is nearly worn out, while its heels have been but little worn, if the shoe has been upon the foot for some time and the horse has been regularly worked. Another peculiarity of the lameness is that when the leg is lifted from the ground the hock moves with a little spasmodic jerk that remotely suggests a string halt action. In some cases the pain caused by work is so great that the animal loses flesh rapidly and doesn't eat well.
Treatment. The only reliable method of cure is by deep point firing and absolute rest for from eight to twelve weeks. Occasionally a severe blistering, with the Spanish fly ointment, or some liquid blister, many of which are sold under the name of " spavin cure," have been known to bring about the desired result; but they are not to be relied upon. There are one or two good operations that are practiced by veterinaries, the description of which will not be necessary in this place.
Young animals recover much more often than older ones; but in a large practice the percentages of recovery amount to about three quarters of all the cases fired, taking them as they come, favorable and unfavorable, together.
All spavined horses, while at work, should have the toes well cut back, the shoe fairly long in the heel, with the heel calks as long as can safely be used.
Ringbone, often called Cling fast, is another one of the disorders, as a result of which deposits of new bone are made round about the diseased parts, which are one or the other of the pastern bones, on either the front or hind legs, more commonly, perhaps, on the hind. The term is properly applied to any such enlargement, whether it forms a "ring around the bone" or consists simply in a small prominence upon one part of the bone only. If the enlargement is above the middle of os suffraginis (see skeleton) it is described as a false ringbone and is of the nature of "splint"; this is not an unsoundness, if the animal trots free from lameness. In true ringbone the bony deposits involve joints of large movement, because of which the disorder is generally incurable.
Causes. These are predisposing and exciting. Among the predisposing causes are hereditary taint, long sloping pasterns, and rheumatism. That breeding from ringboned parents has long been looked upon as a fruitful source of ringbone in the young there is no possible doubt. The exciting causes may be said to consist in any acts or efforts of speed or strength that will produce an over concussion to the pastern bones; strains of the parts, injuries as from blows, pricks with a fork tine, or wounds of any sort that can give rise to inflammation of the bones or synovial membranes.
Symptoms. Lameness occasionally precedes any recognizable deposits of new bone material; and the lameness is peculiar in that,if in a fore limb, the horse puts his heel to the ground first; if in a hind one the toe is the first to touch the ground. Later the pastern, just above the coronet, will be seen to be larger than its fellow, with or without heat or tenderness to the touch; and if the animal is trotted he will show more or less lameness, evidently referable to the region of the foot. Not infrequently a horse is seen with a hard enlargement upon the seat of ringbone, that will show no lameness. Notwithstanding that the writer has known several of these instances in which the animals have continued to go sound for a long time, his practice has always been to reject as unsound any horse having a bony enlargement upon the seat of ringbone and, on the whole, the practice has been proved to be good.
Treatment. Many operations, some of them, as stripping the sole, of a most cruel and useless nature, have been from time to time practiced for the cure of ringbone, without success. The fact is that the disorder is generally incurable; occasionally, repeated blistering with the red iodide of mercury, in young animals, or repeated deep point firing, with Spanish fly blisters, in the older ones, with long rest, will be followed by loss of the lameness and ability to work sound. So, taken all in all, it will probably be as well to keep at work a horse that is no more than moderately lame from ringbone; his chances of recovery are certainly none the less. In shoeing such horses for work, those that put the heel to the ground first should have a thin, wide heeled bar shoe put upon the foot; those that go upon the toes should have high heel calks and no toe calk upon the shoes.
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