A Rare Anatomical Variation of the Brachial Plexus Characterized by the Absence of the Musculocutaneous Nerve

Knowing of anatomical variations is very important during surgery, autopsy and cadaver dissection in the axillary region. In this study, a unilateral variation of the brachial nerve plexus, which is characterized by the absent of the musculocutaneous nerve (MCN), was found in the right arm of a male cadaver. The MCN normally originates from the lateral cord of the brachial nerve plexus and innervates the anterior brachial compartment muscles and lateral coetaneous of the forearm. In this case, the lateral cord of the brachial plexus was joined to the median nerve at the level of coracoid process with no evidence of any nerve braches from lateral cord to the anterior brachial compartment muscles. These muscles were innervated from some branches of median nerve directly.