Non Piercing Variation of Musculocutaneous Nerve

Abstract

Musculocutaneous nerve arise from lateral cord of brachial plexus and run downward & laterally by piercing the coracobrachialis muscle in normal course and further continues as the lateral cutaneous nerve of the forearm after supplying coracobrachialis, biceps brachii and brachialis muscle. Many variations ranging from absence of nerve to non-piercing of the coracobrachialis muscle by the musculocutaneous nerve has been reported. In present study dissections of total 40 preserved upper limbs were carried out & it was noted that in one right upper limb & two left upper limbs, musculocutaneous nerve was not piercing the coracobrachialis. Musculocutaneous nerve passed over coracobrachialis and branch was given to coracobrachialis, biceps brachii and brachialis. It was noted in one case of left upper limb among two having non-piercing course, that after giving branch for brachialis, musculocutaneous nerve joined median nerve in lower part of arm. Surgeons need to consider these anatomical variations while exploring area near axilla and below coracoid process.

"Site of Separation of Musculocutaneous Nerve from Axillary Brachial Plexus: Analysis using Ultrasound- Observational Volunteer Study"

“…We scanned the right upper limb in all the cases to avoid the bias of possible anatomical variations between sides. All our cases were routine healthy male volunteers of the age group of 18-24 to circumvent any possible anatomical variation 14,15 . J.-L. Christophe et al, 16 in their study of patients found the topography of each nerve in the axilla and found the anatomical variations are numerous but all nerves can be identified in a section in 78% of patients.…”