Anatomical variations of the musculocutaneous nerve - A cadaveric study

Abstract

INTRODUCTION: The musculocutaneous (MC) nerve commences from the lateral cord of the brachial plexus, passes inferolaterally and pierces the coracobrachialis while innervating it. It then descends between biceps and brachialis muscles, innervating both and continues as the lateral cutaneous nerve of the forearm. Few studies have been done with regard to variations in origin, course, branching pattern, termination and communications of the MC nerve. These variations are important for anatomists, clinicians, anesthetists and surgeons to avoid unexpected complication as these variations have clinical significance during the surgical procedures and in diagnostic clinical neurophysiology. Therefore the aim of this paper was to study the anatomical variations of the MC nerve. MATERIAL AND METHODS: This descriptive cross sectional study was carried out in the Department of Anatomy, Faculty of Medicine, University of Kelaniya. Dissections were carried out on 50 upper limbs of 25 cadavers to record anatomical variations of the MC nerve. RESULTS: MC nerve was present only in 46(92%) upper limbs. Of the 46 upper limbs where the MC was present, one (2%) did not pierce the coracobrachialis. Communications were seen between MC and median nerve in 06(13%) samples of which 1(17%) was proximal and 5(83%) were distal to the point of entry of the MC into the coracobrachialis and in 4(9%) upper limbs MC nerve rejoins with the median nerve. CONCLUSIONS: It is evident that significant anatomical variations of the MC nerve exist in our study. These variations emphasize the complexities and irregularities of this anatomical structure with regard to surgical approaches.