A rare case: the medical cord of the brachial plexus sandwiched between the axillary and superficial brachial arteries.

We encountered a rare anomaly in the cadaver of a Japanese woman in the medical cord of the brachial plexus including the ulnar nerve and the medical root of the median nerve was sandwiched with the axillary and the superficial brachial arteries. The axillary artery passed inferior and dorsal to the medial cord, branching off the subscapular, anterior circumflex humeral arteries, and the common trunk of the posterior circumflex humeral and profunda brachii arteries, and ended as the inferior ulnar collateral artery. The superficial brachial artery descended ventral to the median nerve and divided into the radial and ulnar arteries in the cubital fossa. We discuss the developmental formation of this anomaly.