A case report on multiple accessory muscles and nerve variations in upper limb

Abstract

During routine dissection of formalin fixed cadavers, the brachial plexus and other upper limb structures were observed for variations. In 65-year-old male cadaver, bilateral upper limb neuromuscular variations were identified. On the left side, median nerve had three roots (one medial and two lateral) and biceps brachii had an additional head which was originating from the mid shaft of humerus and joined with the main muscle at the lower third of arm, and was innervated by musculocutaneous nerve. On the right side, the brachioradialis muscle had an accessory head which took origin from the lateral side of humerus near deltoid tuberosity and joined with main tendon in the lower part of the forearm, and was innervated by radial nerve. The association of nerve variations and accessory muscles is clinically significant. As accessory muscle may lead to nerve or artery entrapment in the limb and is likely to cause palsy or ischemia, knowledge about the neuromuscular variations is clinically significant.