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 tothe muscle. The most common origin of these supernumerary heads is along the humeral shaft. We document a previouslyunreported point of origin for a supernumerary head. Routine dissection of a 10% formalin fixed upper extremity of a 72year old Caucasian male, revealed a tricipital biceps brachii muscle. The third head took its origin from the deep investingfascia of the brachialis muscle and inserted onto the tendon of the short head of the biceps brachii. We believe this to be apreviously unreported point of origin for a supernumerary head of the biceps brachii muscle. Supernumerary heads becomeclinically important as they can be a source of confusion for surgeons operating in this region and may be mistaken for softtissue tumors when they are unilateral. An understanding of such variations is important.