Accessory head of the biceps brachii. Case report demonstrating clinical relevance.

Although anatomic variations in the origin of both the coracobrachialis or biceps brachii have been observed, there have been no previous reports of clinical relevance. In a 22-year-old man, recognition and mobilization of an accessory long head of the biceps brachii was necessary for adequate exposure of the shoulder joint dislocation through a deltopectoral incision.