NORMAL appearance and function of the forearm depends on the existence of freely movable superior and inferior radioulnar articulations, adequate motor power in the musculature of the forearm and the preservation of the normal length relationships between the radius and the ulna. Since pronation and supination of the forearm takes place around an axis which extends from the head of the radius to the head of the ulna, any disproportion in the length of either bone necessarily leads to some disturbance in function of the upper or the lower radioulnar joint.
At the lower joint, the situation is further complicated by the fact that the carpus articulates with the lower end of the radius and not with the ulna. Since the carpus follows the radius, anatomic derangement of the distal radioulnar joint leads to deformity which is characterized by a prominence of the ulnar head on the dorsum of the
MILCH H. SHORT RADIUS. Arch Surg. 1949;59(4):856-869. doi:10.1001/archsurg.1949.01240040865006