Fetlock joint

“ While it serves to constitute a basis from which other joints, when open, are to be considered, due allowance must be made for the fact that, as has been previously mentioned, some articulations when open constitute cause for grave consequences; while with others an open capsule, even when infected, does not cause disturbance enough to be classed as difficult to handle. Moreover, the fetlock joint is admirably suited, anatomically, to bandaging; and when wounded, is easily kept protected by means of surgical dressings. ”

“ Sprain of the fetlock joint is most common in the fore legs, and, as a rule, affects but one at a time. Horses doing fast work, as trotters, runners, steeplechasers, hunters, cow ponies, and those that interfere, are particularly liable to this injury.
Causes.—Horses knuckling at the fetlock, and all those with diseases which impair the powers of locomotion, such as navicular disease, contracted heels, sidebones, chronic laminitis, etc., are predisposed to sprains of the fetlock. ”

“ 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. ”

“ 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. ”

“ Etiology and Occurrence.—Wounds of the fetlock region resulting in perforation or destruction of a part of the capsular ligament are caused by all sorts of accidents, such as wire cuts, incised wounds occasioned by plowshares, disc harrows, stalk cutters and other farming implements. In runaways the joint capsule is sometimes punctured by sharp pieces of wood or other objects. In horses driven on unpaved country roads the fetlock is occasionally wounded by being struck against the sharp end of some object, the other end of which is firmly embedded in the ground. ”

“ Thus it is seen, that when the leg is a weight-bearing member, weight is supported by the bony framework whose constituent parts are joined together by ligaments and tendons and each one of the several bones articulates in such manner that the joint is locked. The articular parts of bones rest upon or against an inhibitory apparatus, and are slightly flexed, as in the carpus, or considerably flexed such as in the fetlock joint when weight is being supported. ”

“ Such legs are called ‘gummy.’ The fetlock joint should be large and flat laterally, its posterior aspect being well-defined and prominent. The pastern bones should neither be too long, short, oblique, or straight. If the pastern is long it is necessarily oblique, and therefore weak; if short it is upright, and the severe concussion so produced causes ringbones, windgalls, navicular disease, &c., besides causing the horse to be rough and unpleasant to ride. ”

“ If the inside wall is the higher, the ankle is thrown outward, so that the fetlock joints are abnormally wide apart and the toes close together. Animals with this deformity are "pigeon-toed," and are prone to interfere, the inside toe striking the opposite fetlock. If but one foot is affected, the liability to interfere is still greater, for the reason that the fetlock of the perfect leg is nearer the center plane. ”

“ The suspensory ligament of the fetlock is considered an interosseous muscle, on account of the red fleshy striations which it contains, and from certain relations which it forms with the tendon of the common extensor of the digits or anterior extensor of the phalanges. This ligament (Fig. 75, 26; Fig. 77, 13) , which plays an important part in the standing position as a support of the foot, is a fibrous band situated between the tendons of the flexors of the digits and the principal metacarpal. ”

“ In cases where the abnormality has been brought about by wounds to the flexor tendons, the alteration in the direction of the limb is often so great as to produce 'knuckling over' of the fetlock. This, to a very great extent, may be remedied by the use of a shoe with calkins and an extended toe-piece (see Fig. 84) . ”

“ Joints in which movement is restricted within narrow limits, such as the hock or fetlock, are most liable to such injuries, which also occur in very freely movable articulations like the shoulder and stifle. ”

“ There are no contracted fascial bands, and, as a rule, the skin is normal, but occasionally a small longitudinal fold may be present in the angle of flexion. In rare instances the resistance to extension is capable of yielding suddenly with a spring-like action, and [46] a similar movement recurs as the joint is replaced in the position of flexion. These cases are usually classed with the condition known as “trigger finger.” The contraction also occurs in the metacarpo-phalangeal joint, but very rarely attains a degree marked enough to attract the attention of patient or surgeon. ”

“ The transverse diameter of this joint is long, thus giving it contacting surfaces that are sufficiently extensive to minimize the strain upon the mesial and lateral ligaments (internal and external lateral common ligaments) . Motion is that of flexion and extension; slight rotation is possible when the position is that of flexion. While supporting weight the carpus is fixed in position by a slight dorsal flexion, but undue dorsal flexion is prevented by the flexor muscles and tendons and volar-carpal or annular ligament, together with the superior check ligament. ”

“ Gregory takes into five separate pieces, viz., two fetlock straps, a1, a2; a chain, b, having a swivel point, c, in the middle; and two double pot-hooks, d1, d2, which pass through eyes in the fetlock straps, and also through the end links in the chain. The two ends of both, d1 and d2, are thickened and pierced, so as to admit of tying a thong across their mouths, as shown on one side of d2. The fetlock strap is made of a strip of thick leather, folded lengthways down its middle, and having its edges sewn together. The sewn edge should always be the uppermost, when on the horse's legs. ”

“ The modes of reduction are these: by flexion at the knee, or by sudden calcitration, or having rolled a swathe into a ball, and fixed it in the ham, the patient's body is to be suddenly dropped on its bended knees. Dislocation backward, also, as in the case of the elbow, may be reduced by moderate extension, and to either side, either by flexion or calcitration, but also by moderate extension. The adjustment is the same in all cases. In dislocations backward which are not reduced, the patient cannot bend the joint, but neither can he, to any great extent, in the other varieties ”

“ The fetlock, as it is termed, is found in all horses, especially in those of the northern breed, and from its position is an admirable guard against thorns, furze, flints, or other bodies, to which the pastern, without it, is so much exposed. The only excuse for this foolish practice is, that it is customary, and makes a horse look clean about the legs; and this notion is carefully preserved, and impressed upon the minds of those inexperienced in horses, by the men employed to operate on the occasion. ”

“ The subject requires much more investigation, but there is every reason to believe that it is a tendon which has sunk into the joint, though whether that of the pectineus is doubtful, since the intra-capsular tendon comes from the ischium in Reptiles. In many Mammals, and among them the Orang, there is no ligamentum teres. In others, such as the Armadillo, the structure has not sunk right into the joint, but is connected with the pubo-femoral part of the capsule.
The Knee Joint is a hinge formed by the condyles and trochlea of the femur, the patella, and the head of the tibia. ”

“ An open operation is seldom necessary.
Dislocation forward is rare. It results from forced flexion of the thumb with abduction, tearing the posterior and medial collateral ligaments. The deformity is characteristic: the rounded head of the metacarpal projecting behind the level of the joint, while the base of the phalanx forms a prominence among the muscles of the thenar eminence.
Reduction is easily effected by making traction on the phalanges and carrying out movements of flexion and extension. ”

“ Every articulation in the limbs possesses a capsular ligament, and all, except the shoulder-joint, have several funicular (cord-like) ligaments. The capsular ligaments are lined upon their inner face with a delicate membrane (synovial membrane) which secretes the synovia, or “joint-water,” whose function is to lubricate the joint and prevent friction; they enclose the joint in a sort of air-tight cuff or sack. The funicular ligaments are very strong [Pg 22] and often large, and are the chief means of union of the bones. ”

“ In itself, inflammation of the carpal flexors is not a condition which is likely to prove troublesome, but because of carpal involvement (which is often present) the cause of the trouble remains, and inflammation of the carpal flexors recurs or becomes chronic and contraction of tendons results.
Symptomatology.—Inflammation of the carpal flexors, when acute and uncomplicated, is characterized by a painfully swollen condition of the affected tendons. No weight is borne upon the affected leg and the carpal joint is flexed. Mixed lameness is present. ”

“ Thus, we observe, that two very different substances enter into the composition of a joint. The ligament, very unyielding, affords strength, while the cartilage, elastic and moist, gives ease and smoothness of motion. The amount of motion provided for varies greatly in different joints. In some there is none at all, as in the skull, where one bone is dove-tailed into another by what are termed sutures. Others have a hinge-like motion, such as those of the elbow, wrist, ankle, and knee ”

“ The most marked swelling is over the line of the articulation on the anterior and posterior aspects of the joint. There is usually some effusion into the sheaths of the tendons passing over the joint, and in some cases on moving the fingers a peculiar creaking, which may simulate crepitus, can be elicited. There is marked tenderness on making pressure over the line of the joint, as well as over one or other of the collateral ligaments, depending upon which ligament has been over-stretched or torn. Movements that tend to put the damaged ligaments on the stretch also cause pain. ”

“ The changes in the joints involve almost exclusively the synovial membrane and the ligaments; they consist in cellular infiltration and exudation, resulting in the formation of new connective tissue which encroaches on the cavity of the joint and gives rise to adhesions, and by contracting causes stiffness and deformity. The articular cartilages may subsequently be transformed into connective tissue, with consequent fibrous ankylosis and obliteration of the joint. ”

“ In movable, or true joints the articular surface of each bone is covered by cartilage. The bones are held together by ligaments, the capsular one often surrounding the joint and enclosing the synovial membrane. In some joints there is a pad of fibrous cartilage interposed between the two articular cartilages. Such a pad, called a meniscus, adds to the elasticity and the free movement of the joint. Movable joints form the most numerous class; they are for the most part found in the limbs. ”

“ The flexors are not antagonized and if there be an open wound the parts soon become contaminated; or, in rupture, if animals travel about very much, there soon occurs necrosis of the tissues of the anterior fetlock region and the condition is rendered incurable. Cases are reported of animals that have suffered rupture of the long digital extensor and the subjects learned to throw the member forward during extension, substituting for the extensor tendon the pendulum-like momentum which the foot affords when so employed ”

“ When attacking the anterior half of the cartilage, the close contiguity of the joint renders the disease of a more serious nature. It is then that we have acute pain, and with it extreme lameness, for in this position it is more than likely that we have involved either the synovial membrane of the articulation or the tops of the sensitive laminæ. It will be remembered that here the synovial membrane protrudes as a small sac between the antero- and postero-lateral ligaments of the joint. ”

“ He may fall to the ground and be unable to rise. On examination, the knee is found to be fixed in a slightly flexed position; and while the surgeon may be able to carry out movements of flexion to a considerable extent without increasing the pain, any attempt to extend the joint completely is extremely painful. Tenderness may be elicited on making pressure to the medial side of the ligamentum patellæ in the groove between the femur and the tibia, but the meniscus cannot be recognised by palpation. Considerable effusion rapidly takes place into the synovial cavity. ”