Median Nerve Branch Innervating the Brachialis Muscle: A Case Report

We observed a slender nerve branch of the lateral root of the median nerve innervating the brachialis muscle, which is normally innervated by the musculocutaneous nerve, at the left arm of a Korean male (age, 74 years). The present nerve branch was accompanied with the communicating branch between the median and musculocutaneous nerves and supplied to the medial inferior portion of the brachialis muscle. The spinal root origins of this branch were C5 and C6. The nerve fiber number of the nerve branch innervating the brachialis muscle was 328. This variation may be very rare case and was different from previous observation.