The Upper Arm and Forearm

The bone of the upper arm, the humerus, has already been described (pp. 344–346); the bones of the forearm are the radius and ulna, which in the anatomical position lie more or less parallel to each other with the radius on the lateral side. The muscles in the upper arm form an anterior flexor and posterior extensor group which move the forearm at the elbow. Similar groups in the forearm produce flexion and extension of the hand and digits. The nerves and arteries continue from the axilla into the more distal parts of the limb and the veins, deep and superficial, pass upwards from the forearm through the upper arm to the axilla. The cutaneous nerves of the forearm arise in the axilla and upper arm.