Absence of the musculocutaneous nerve together with unusual innervation of the median nerve.

During routine anatomical dissections, absence of the musculocutaneous nerve was determined in a 58-year-old male cadaver. Moreover, the biceps brachii and brachialis muscles were innervated by two separate branches which divided from the median nerve instead of the musculocutaneous nerve. From a branch that divides from the main trunk of the median nerve at nearly the middle of the arm a motor branch again divided that innervated the brachialis muscle and a sensory branch that conveyed the sense of the lateral part of the forearm. Furthermore, it was found that the brachial artery divided into its terminal branches, the radial and ulnar arteries. We believe that this rare variation of the median nerve will shed light upon surgical procedures involving the median nerve.