Fractures of the large pastern are perhaps the most common of all affecting the limbs of the horse.

They mostly take an oblique direction, extending from above downwards towards the outer or the inner side (fig. 339), or pass vertically downwards from the upper to the lower extremity. Less frequently the breakage is transverse, in which case it mostly occurs towards the lower extremity (fig. 340), and is very frequently comminuted.

In oblique fractures the division usually extends into the fetlock joint, while in those taking a vertical course it may also involve the joint formed with the small pastern. In young horses they are most frequently partial, and take the form which is commonly termed "split pastern". In these cases there is no displacement, and treatment is thereby favoured.

Fracture of this bone is most commonly met with in race-horses, hunters, and chasers. In the first it results more especially from slips, false steps, twists, and striking the toe in the ground while going at great speed. In hunters and chasers it also occurs as the result of jumping into roads or travelling through deep holding-ground, or dropping the feet into holes.

Symptoms

Following the mishap, there is sudden and severe lameness. If the fracture is comminuted or attended with displacement the leg is held in the air, and is incapable of bearing weight.

Fig. 339. - Oblique Fracture of Suffra-ginis.

If the foot be rotated or forcibly flexed on the fetlock, crepitus or rubbing of the broken pieces will be felt. Great sensibility to pressure along the surface of the bone soon appears, accompanied by a firm diffused swelling. In split pastern the lameness, although sometimes considerable, is less severe, and there is usually no crepitus. The swelling may be inconsiderable, and the existence of a fracture altogether overlooked.

Treatment

No time should be lost in placing the animal in slings. The shoe should be removed, and the stable littered with 3 or 4 inches of saw-dust or peat-moss. If there is no displacement, which will be readily determined by the undisturbed outline of the pastern, a starch bandage should be applied at once. In making the application, the hollow of the heel should first be filled in with a pad of tow, over which the bandage should be rolled and carried over the fetlock joint from the coronet, nearly as high as the knee. In those cases in which displacement occurs, the parts should be readjusted and the bone supported by a starch bandage or some more suitable splint.

A light, spare diet should be prescribed, and a little linseed-oil may be incorporated with it night and morning until the bowels are gently acted upon. All that is now needed is to avoid any sudden excitement, and to keep the animal perfectly quiet.

So soon as he begins to throw his weight upon the limb, and to continue it, the bandage may be removed. More or less enlargement will be found to have developed on the bone in the form of a reparative callus, and subsequent treatment must be directed towards effecting its reduction. For this purpose a repetition of blisters must be applied over the part during a continuance of rest. In some cases a large ring-bone, with more or less lameness, remains as a permanent result of the fracture, while in others but little enlargement follows, and the action is in no respect affected by it.