Unusual origin of three headed biceps brachii muscle

Abstract

The biceps brachii is one of the most variable muscles in the human body in terms of the number of heads contributing to the muscle. The most common origin of these supernumerary heads is along the humeral shaft. We document a previously unreported point of origin for a supernumerary head. Routine dissection of a 10% formalin fixed upper extremity of a 72 year old Caucasian male, revealed a tricipital biceps brachii muscle. The third head took its origin from the deep investing fascia of the brachialis muscle and inserted onto the tendon of the short head of the biceps brachii. We believe this to be a previously unreported point of origin for a supernumerary head of the biceps brachii muscle. Supernumerary heads become clinically important as they can be a source of confusion for surgeons operating in this region and may be mistaken for soft tissue tumors when they are unilateral. An understanding of such variations is important. Keywords: biceps third head; elbow; shoulder; supernumerary biceps brachii