These are small, rounded, fluctuating enlargements occurring in the neighbourhood of joints, more especially on the outer and inner aspects of the fetlocks, and also on the hocks and knees (fig. 381). Wind-galls are divided into two classes, according to the part they implicate. In one case they result from a dropsical and unduly distended state of the capsular membrane of the joint with synovia, when they are known as "articular wind-galls". In the other they are due to a similar state of distension of the synovial sheath of a tendon, as in thoroughpin.
They appear either as isolated swellings or in rows of two or three. To the uninitiated it might appear that each of the wind-galls observed about the fetlockjoint is a separate and distinct sac. This, however, is not necessarily the case. For the most part they result from a distended state of the synovial sheath that invests the flexor tendons from a point just above the fetlock to the foot. That the swelling is not observed along the entire length of the sheath results from the fact that at certain points it is tightly bound down by strong ligaments, while the intervening spaces where the bulging takes place offer only slight resistance to its outward pressure; all the same, there is a general over-fulness of the sheath from one end to the other.
Fig. 381. - Wind-Galls. A, Tendon of the Flexor Perforatus. The swollen bursse or wind-galls are shown at x x.
Wind-galls, like the kindred ailment thoroughpin, are unquestionably hereditary. Besides this predisposing influence, it is also observed that horses of lymphatic temperament, i.e. such as have a thick skin, coarse hair, fleshy legs, exhibit a special liability to the disease, as do also animals with heavy fleshy bodies and small limbs.
The exciting causes are long-continued severe work, which is especially operative in the case of young immature animals and such as are indifferently nourished. Repeated sprain to the tendinous sheath from heavy draught, slipping, and other forms of violent exertion very largely conduce to bring about the disease.
Wind-galls are readily identified as small boggy swellings in the vicinity of joints, varying in size from a hazel-nut to a small hen's egg. In the fetlock-joints they occur on the inner and outer side at the same time. The more material enlargements appear behind and above the fetlock-joint between the suspensory ligaments and the flexor tendons. They usually come by slow growth, and are at first soft and yielding, but as they increase in size they get hard and tense, especially when the foot is on the ground. Excepting when associated with rheumatism or sudden sprain they seldom give rise to acute lameness, and it is only when of considerable size, and the mechanical play of the tendons and joint are interfered with, that the action becomes materially disturbed. At this time there is more or less heat in the part, and digital pressure occasions marked pain.
In this connection it may be said that the best and most lasting results are obtained when treatment is resorted to in the early stages of the disorder, while the walls of the joint capsule or tendon-sheath are still free from serious structural change. When by protracted irritation and neglect they have become thickened and callous it is hopeless to think of bringing the membrane back to a normal state, although further advance of the disorder may in some measure be kept in check.
Whether the disease results from undue wear or inherent weakness of the parts, withdrawal from work is the first step to be observed. What should follow will depend upon the stage and duration of the malady. If it is of but recent occurrence, a mercurial charge of pitch-plaster applied to the legs from the middle of the canon to the coronet, and a few weeks at grass, may be all that is necessary. In more advanced cases, a course of massage, cold-water irrigation, and tight bandages put on wet is to be followed by a repetition of iodine-blisters at intervals of a fortnight during six or eight weeks' rest. Before adjusting bandages in these cases, it is an advantage to roll up pieces of tow into fairly firm pads and bind them on the wind-galls. By adopting this course pressure is ensured on the spot where it is most needed, and absorption is promoted. In the more aggravated cases, where, in addition to distension of the capsule of the joint or tendon, there is also considerable thickening of the sac, deep firing and blistering will require to be resorted to, and further benefit may result if iodide of potassium be given daily in two- or three-dram doses. In the more extreme cases, involving the tendon-sheath only, it may be necessary to remove the fluid by means of the aspirator, and inject into the cavity a solution of iodine to prevent further filling of the sac.