Dorsal metacarpal disease is the inflammation of the bone covering the front of the cannon, and usually results from the concussive force caused by strenuous physical activity. It commonly occurs in the forelimbs, rarely in the hindlimbs.

This is a common condition of the front cannon bones of young (usually 2 year old) racehorses in training. It is common in the United States, where horses race on comparatively harder track surfaces.

Bone is a very dynamic tissue, constantly laying down or strengthening in response to the loads placed on it. The cannon bone can be thought of as a hollow tube. The thickness and hardness of the wall (especially on the front and inside surfaces of the bone) increase under the load of training.

Bucked shins are repetitive microscopic fractures that occur in the front wall of the cannon bone. A bone bridge (callus) and then injury recurs. They cause pain to pressure on the cannon, stiffness, thickness of the front wall of the bone, if not obvious lameness and poor performance.

Left unmanaged, horses that continue in unmodified training may be at risk for more serious stress fracture.