Forearm

Abstract

The forearm (Fig. 640) is that part of the upper extremity which is between the elbow and the wrist. The anterior (volar) region contains those structures which are anterior to the plane of the radius and the ulna; these include the internal and the external muscle groups which arise from the medial and the lateral epicondyles, respectively. The posterior (dorsal) region contains the extensor muscle group, which composes the bulk of this region. When the forearm is in full supination, it appears as a cone which is flattened anteroposteriorly. Muscle masses which arise from the humeral epicondyles increase its transverse diameter near the elbow. Distally, the forearm loses its bulk because of the transition of the fleshy muscles into their respective tendons. The shafts of the radius and the ulna can be felt superficially in the distal part of the forearm.