Analysis of the Morphological Variations between Musculocutaneous Nerve and Median Nerve-A cadaveric study

Abstract

Background: Musculocutaneous nerve, a branch from the lateral cord of brachial plexus supply the muscles of the front of the arm. Musculocutaneous nerve has frequent variations in arm. Aim: To analyze the morphological variations between musculocutaneous nerve and median nerve in the arm. Materials and Method: 56 upper limbs belonging to 28 embalmed cadavers (M: F: 20:8) donated over last 3 years in the Anatomy Department, SMIMER Medical Collage, Surat were utilised for this study. The dissections of the upper limbs were performed as per Cunningham’s manual. The variations and/ communications between musculocutaneous nerve and median nerve if any were identified and documented. Results: Variations were encountered in 12 (21.43%) out of 56 upper limbs of the present study. In 6 upper limbs below the coracobrachialis, musculocutaneous nerve and median nerve showed communicating rami. In 1 upper limb musculocutaneous nerve was giving larger communication to median nerve as third root. In 2 upper limbs medial cord formed the median nerve and fibres from musculocutaneous nerve join the median nerve as lateral root below coracobrachialis. In 1 upper limb musculocutaneous nerve completely fused with median nerve after supplying coracobrachialis. In 2 upper limbs muculocutaneous nerve was absent and median nerves was supplying the flexor muscles of the arm and were associated with the 3rd head of biceps brachii muscle. Conclusion: The data obtained from the study were in the mid-range of previous studies. Awareness regarding such variations as well as communications is important for surgeons, orthopaedics and anaesthetist that are treating the lesions of shoulder and arm region. Keywords: Musculocutaneous Nerve, Median Nerve, Communication Branch (Ramus), Coracobrachialis Muscle