Anatomic course of the medial cutaneous nerves of the arm.

The medial antebrachial cutaneous nerve and the medial brachial cutaneous nerve were dissected in twenty fresh cadaver extremities. These nerves have a variable number of cutaneous branches ranging from four to twelve, with an average of eight. Branches always originated medially in both nerves and ran in an anterolateral direction. In all the medial antebrachial cutaneous nerves, there were three to five terminal branches directly overlying the medial epicondyle and supplying the skin over the olecranon. The course of this nerve is predictable relative to the basilic vein and the medial epicondyle. There was a ninety percent incidence of communication between the medial brachial cutaneous nerve and the intercostobrachial cutaneous nerve. The standard incision used for surgery of the ulnar nerve at the elbow will cut the terminal branches of the medial antebrachial cutaneous nerve one hundred percent of the time, and the terminal branches of the medial brachial cutaneous nerve eighty percent of the time, if they are not identified. A posterior approach for transposition of the ulnar nerve would avoid damage to these nerves.