Brachial plexus begins from ventral rami of C5 to T1 segment of spinal cord. Brachial plexus has 3 cords-medial, lateral & posterior. The Musculocutaneous nerve arises from the lateral cord of the brachial plexus, passes inferolaterally and then pierces through the coracobrachialis⁸and it descends between the biceps and the brachialis, sending branches to both and continues as the lateral cutaneous nerve of the forearm⁶. The musculocutaneous nerve is responsible for the innervation of the flexor musculature of the elbow and the skin sensitivity from elbow to wrist¹⁵. Musculocutaneous nerve shows wide variations which can have clinical and surgical importance⁸. Present variation was observed during routine dissection on cadavers in the department of anatomy, Rajah muthiah medical college, Chidambaram. In the present study out of 50 upper extremities, 4% of musculocutaneous nerve did not pierce the coracobrachialis muscle on the right side and 4% of musculocutaneous nerve did not pierce the coracobrachialis muscle bilaterally and gave separate branch. 2% had a communicating nerve between the medial nerve and the musculocutaneous nerve after piercing coarcobrachial’s muscle.2% had no musculocutaneous nerve.

1. Abhilasha Priya, Chandni Gupta, Antony Sylvan D'souza., Cadaveric Study of Anatomical Variations in the Musculocutaneous Nerve and in the Median Nerve., Journal of Morphological Sciences Vol. 36 No. 2/2019
2. Bharti A, Vaishali MP, Makarand VA. Variations in the formation and relation of median nerve. Int J Anat Res. 2015; 3(3):1298-1301.
3. Bhattarai C, Poudel PP unusual variation in musculocutaneous nerves. Kathmandu Univ Med J 2009., vol-7:408-410.
4. Henry W, Holinshed WH. The Back and Limbs. In: Anatomy for surgeons: vol.3. 3rd Ed., Philadelphia, Harper & Row.1982; p366.
5. Ihunwo AO, Osinde SP, Mukhtar AU: Distribution of median nerve to the muscles of the anterior compartment of the arm. Cent Afr J Med 1997; 43:359-60.
6. Jamuna M.,Amudha G., A Cadaveric Study on the Anatomic Variations of the Musculocutaneous Nerve in the Infraclavicular Part of the Brachial Plexus., Journal of Clinical and Diagnostic Research. 2011 November (Suppl-1), Vol-5(6): 1144-1147
7. Joshi SD, Joshi SS, Athavale SA: Hitch- hiking fibers of the lateral cord of the brachial plexus in search of their destination. J Anat Soc India 2008., 57:26-9.
8. Jyoti, Anshu Sharma, Mahesh Sharma, Ramandeep Kaur., Variation of Musculocutaneous Nerve in Infraclavicular Part of Brachial Plexus, North States Journal of Anatomy, 2018, Vol. 3, No.1
9. Maheria PB, Chinna NG, Khubchandani PR, et al. A Study of Anatomical Variations of the musculocutaneous nerve. Int J Res Med 2013;2(02):1–4
10. Morgan BA, Tabin C. Hox genes and growth: early and late roles in limb bud morphogenesis. Dev suppl: 1994; 181-6.
11. Nakatani T, Mizukami S, Tanaka S: Three cases of the musculocutaneous nerve not perforating the coracobrachialis muscle. Acta Anat Nippon 1997a; 72:191-4
12. Nayak S, Samuel VP, Somayaji N: Concurrent variations of the median nerve, the musculocutaneous nerve and the biceps brachii muscle. Neuroanatomy 2006; 5:30-2.
13. Patel SJ, Patel RK. Bhatt C et.al. Variation of musculocutaneous nerve in arm with additional muscular slip in forearm. Int. J. Anat.Physiol.2013; 2(3):20-3.
14. Prasada Rao PVV, Chaudhary SC. Absence of the musculocutaneous nerve: Two case reports. Clin Anat 2001; 14:31-5.
15. S.Chitra, M. Sobana., Anatomical study of variations of Musculocutaneous nerve., National Journal of Clinical Anatomy., vol-5(3), pg-143-147 (2016).
16. Romanes G.J. Cunningham’s Textbook of Anatomy, 12th edition. Oxford University Press, London. 1991; 774-826.

Dr Karthikeyan A

PG Student, Department of Anatomy, Rajah Muthiah Medical College and Hospital, Chidambaram