A unique variation of musculocutaneous nerve and median nerve and its clinical significance

Abstract

The musculocutaneous nerve (MCN) and median nerve (MN) are branches of the brachial plexus that innervates the anterior compartment of the upper limb. Although the nerves have different course and distribution, communication between median and MCNs may result from an altered course of the nerve fibers during their development. Rare patterns of communication were found bilaterally in a male cadaver. The right MCN was fused with the MN for a length of 3 cm. The fused intermediate segment supplied biceps brachii, while the unfused segments supplied the other anterior arm muscles. The variation is a unique type of transposed nerve fibers supplying the brachial flexors and is a deviant of the defined patterns of communications. On the left side, a communication twig coursed anteriorly to the axillary artery from MCN to the MN. The surgical, neurophysiological, and embryological relevance of such variations is of great clinical significance.