Study of the anatomical variations of the musculocutaneous nerve

OBJECTIVE: To study the anatomical variations of the musculocutaneous nerve.

METHODS: Fifty-four arms from embalmed adult cadavers were utilized for this investigation. They were carefully dissected and examined for any anatomical variations of the musculocutaneous nerve. This study was performed at the Department of Anatomy, King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia between 2001 and 2003.

RESULTS: Four anomalies of the musculocutaneous nerve were found in this study. One case showed that the musculocutaneous nerve pierced the coracobrachialis muscle and passed inside the muscle for some distance. The nerve pierced the coracobrachialis muscle again, and it ran downward and medially and joined the median nerve at the middle of the arm. The brachial artery was sandwiched between the musculocutaneous and the median nerves. Three cases demonstrated that the musculocutaneous nerve did not pierce the coracobrachialis muscle and passed downward and medial to it. The nerve joined the median nerve at the junction of the upper third with the lower two-thirds of the arm. The musculocutaneous nerve was completely absent in one case. In another case, the musculocutaneous nerve originated from the upper part of the median nerve.

CONCLUSION: The knowledge of the anatomical variations of the musculocutaneous nerve may have clinical and surgical implications.