Fracture of this bone is comparatively frequent. Its greater length, more exposed position, and less ample protection by muscles than the femur render it more liable to succumb to external violence.

The internal surface of the bone is quite superficial, having no other covering than the skin. This is its most vulnerable point, and when sharp forcible blows are applied to it, it not unfrequently splits or breaks.

Kicks, blows, false steps, collisions with cart-shafts, carriage-poles, and stone walls, and violent struggling when cast either by accident or designedly for the purpose of an operation are the causes by which it is chiefly produced.

Symptoms

The outward manifestations resulting from the mishap will depend upon the more or less completeness of the fracture. Sometimes the bone is only partially broken through, and, the parts being maintained in their natural position, comparatively little pain or inconvenience is suffered; so little, indeed, that in some cases the nature of the injury remains undetected for days and weeks, until by the strain of work the fracture is rendered complete by the parts being torn asunder, or the fragments becoming displaced in the act of lying down or rising from the recumbent posture. In such circumstances the evidence of fracture becomes clear and decisive; the horse fails to support weight on the injured limb, which, when raised from the ground, hangs limp and pendulous, and crepitus is readily detected in it.

Partial fracture may provoke more or less lameness, the seat of which may or may not be indicated by swelling. But in the absence of swelling, pressure applied over the surface of the bone will afford material evidence of the existence of fracture.

Treatment

Where the fracture is complete the prospect of restoring the horse to a state of usefulness is very remote, indeed so much so that it is only where high value is set upon the patient for breeding purposes that the result would be likely to prove at all satisfactory. In this case the limb should be enclosed in a strong pitch plaster, laid on in a succession of layers from below the hock as high as the stifle.

Further support may be given to the broken fragments by strips of thick cardboard let into the plaster over the region of the fracture. With this should be conjoined the support of slings and perfect rest.