Nerve · Upper arm

Medial brachial cutaneous nerve

Nervus cutaneus brachii medialis

The smallest branch of the medial cord of the brachial plexus, and the smallest named nerve in the axilla. It runs down the inner side of the arm, first behind then medial to the axillary vein, and supplies a narrow strip of skin on the inner and back of the arm as far as the elbow. Its distinguishing feature is a partnership: in the axilla it joins the intercostobrachial nerve, a branch of the second intercostal nerve that has crossed out of the chest wall. That junction is one of the few places where a nerve from the trunk and a nerve from the limb plexus share a territory of skin.