Anatomical variations of the musculocutaneous nerve: a cadaveric study

Bhaskar B.Reddy and P.G.Khanwalkar

Background: The musculocutaneous nerve begins opposite the inferior border of the pectoralis minor muscle, pierces the coracobrachialis and continues distally between the biceps and brachialis. After supplying all three muscles of the anterior compartment of arm, the nerve emerges lateral to the biceps as the lateral cutaneous nerve of the fore arm. Researchers have been reported on the relationship in between the musculocutaneous nerve and the coracobrachialis muscle as well as the connections between the musculocutaneous nerve and median nerve.
Methods: During routine dissections in the Department of anatomy, Shyam Shah Medical College, Rewa, we observed and analyzed a total of 60 upper limbs from 30 adult cadavers to record anatomical variations in the musculocutaneous nerve.
Results: We found 3 male cadavers with variations in the course and branches of the musculocutaneous nerve. The musculocutaneous nerve was not piercing the coracobrachialis muscle left side in two cases and right side in one case. In all cases, it was arising from Lateral cord of brachial plexus and directly supplying biceps and brachialis muscles. Then it continued as lateral cutaneous nerve of the fore arm.
In one case of male cadaver, on the left side, musculocutaneous nerve was piercing the coracobrachialis but coracobrachialis muscle got its nerve supply by extra branch arising from the proximal end of musculocutaneous nerve.
Conclusions: The results show that the musculocutaneous nerve has significant variations. Knowledge of such anatomical variations is helpful for surgeons treating neoplasm or peripheral nerve repair.

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