Accessory Heads of Biceps Brachii Muscle its Embryogenesis and Clinical Implications: Cadaveric Study

BACKGROUND: Biceps brachii is an elongated two-headed fusiform muscle of the anterior compartment of the arm which crosses the shoulder as well as the elbow joint. It assists in flexion of the shoulder joint and elbow joint and powerful supinator of the forearm. It also assists in the abduction of the shoulder joint. Accessory heads of biceps brachii muscle not only give additional strength to the joints, at the same time, they may also simulate soft-tissue tumors that can result in neurovascular compression. AIMS AND OBJECTIVES: Accordingly, the aim of this study was designed to evaluate the prevalence of accessory heads of biceps brachii muscle in human cadavers. MATERIALS AND METHODS: This study was conducted on 107 formalin embalmed human cadavers (male 62 and 45 female), and dissections were performed in accordance with the institutional ethical standards and the Indian Anatomy Act. RESULTS: Out of 107 cadavers, three-headed biceps brachii was noted in 18 cadavers (16.82%) associated with the unusual course of musculocutaneous nerve. Rare and unusual unilateral five-headed biceps brachii was noted in one male cadaver (0.93%). All accessory heads noted in this study were supplied by the separate branches of musculocutaneous nerve except the humeral head of five-headed biceps, which was supplied by the radial nerve. CONCLUSION: Awareness of these anatomical variations, knowledge is necessary for radiologists, anesthetists, physiotherapists, and orthopedic surgeons to avoid complications during various radiodiagnostic procedures or surgeries of flexor deformities of the upper arm and forearm.