Musculocutaneous Nerve Not Piercing the Coracobrachialis Muscle and also having Communication with Median Nerve - A Case Report

During undergraduate routine cadaver dissection, a rare anatomic variation was encountered in the right sided upper limb of the human male cadaver. The variation was unilateral. A very thin lateral root of median nerve was observed. Musculocutaneous nerve from lateral cord was very thick compared to the opposite limb. Muculocutaneous nerve descended downwards without piercing the coracobrachialis and gave muscular branch to coracobrachialis from its lateral side. At the lower border of teres major muscle there was a communicating branch which was observed joining the median nerve. On further dissection it was observed that the median nerve acquired larger thickness. Further continuation of musculocutaneous nerve became very thin. Further course of median and musculocutaneous nerve are normal as that of opposite side limb. It is important to be aware of such variations while planning a surgery in the region of axilla and arm as these nerves is more liable to be injured during surgical procedures. Possible embryological explanations and clinical significance have been discussed.