Bilateral Supernumerary Heads of Biceps Brachii.

ABSTRACT

The Biceps brachii is a muscle of flexor compartment of the arm. The biceps brachii muscle shows variation in the number of heads, with an estimated 9–22% of all people having a supernumerary head. Themost common variation is third head, but four, five, or even seven heads have been reported. Although supernumerary heads of the biceps brachii muscle have been frequently reported, bilateral asymmetric occurrence of supernumerary heads is relatively rare. During a routine cadaveric dissection at the Department of Anatomy, National Medical College, Birgunj, Nepal, we encountered bilateral supernumerary heads of the biceps brachii muscle; Three heads on the right arm and four heads on the left arm in a 68 year old male cadaver. These additional heads were supplied by branches from the musculocutaneous nerve. No additional anomalies were found on the remainder of both upper limbs of the same cadaver. It may cause compression of surrounding neurovascular structures or itmay lead to variation of normalmechanical actions and also can cause erroneous interpretation during routine surgeries.