Anat Cell Biol.  2022 Jun;55(2):130-134. 10.5115/acb.22.022.

Anatomical variation of median nerve: cadaveric study in brachial plexus

• Ghosh B
• Alam Dilkash MN
• Prasad S
• Sinha SK

• KMID: 2531198
• DOI: http://doi.org/10.5115/acb.22.022

Abstract

Median nerve is formed by lateral root from lateral cord and medial root from medial cord of brachial plexus. Formation of median nerve occur in front or lateral to axillary artery in axilla. In the present study we observed anatomical variations of median nerve formation in the brachial plexus. We examined formalin fixed 60 upper limbs from 30 adult cadavers (15 males and 15 females) which were above the age 40 years from the department of Anatomy. All the cadavers were dissected on both sides according to Cunningham’s Manual of Practical Anatomy. Normal formation of median nerve by two roots noted in 42 (70.0%) of upper limb specimen. Variation of median nerve formation noted in 18 (30.0%) upper limb specimen. Three roots taking part in the formation of median nerve in 13 (21.7%) upper limb specimen where additional root coming from lateral cord of brachial plexus. Four roots taking part in formation of median nerve in 3 (5.0%) upper limb specimen, where additional roots coming from lateral cord and posterior cord of brachial plexus. Lateral root crossed the axillary artery anteriorly to join with medial root lying medial to axillary artery. The median nerve formed medial to third part of axillary artery. Additional communication with musculocutaneous nerve with median nerve seen in 2 (3.3%) upper limb specimen. Knowledge of such anatomical variations is of interest to the anatomist and clinician alike. Surgeons who perform procedures involving neoplasm or repairing trauma need to be aware of these variations. Median nerve variation may lead to confusions in surgical procedures and axillary brachial plexus nerve block anesthesia.

Keyword

Brachial plexus; Median nerve; Anatomical variation; Anesthesia; Nerve block

Figure

• 

  Fig. 1 Photograph of formation of median nerve (MN) by two roots. LC, lateral cord; LR, lateral root; MR, medial root; MCN, musculocutaneous nerve; AA, axillary artery; BB, biceps brachii muscle; CB, coracobrachialis muscle; UN, ulnar nerve.

• 

  Fig. 2 Photograph of formation of median nerve (MN) by three roots. LC, lateral cord; AA, axillary artery; AV, axillary vein; CB, coracobrachialis; MCN, musculocutaneous nerve; LR1, lateral root first; LR2, lateral root second; MR, medial root; UN, ulnar nerve.

• 

  Fig. 3 Photograph of formation of median nerve (MN) by four roots. LC, lateral cord; AA, axillary artery; AV, axillary vein; CB, coracobrachialis; SHBB, small head of biceps brachii muscle; PMn, pectoralis minor muscle cut end; MCN, musculocutaneous nerve; LR1, lateral root first; LR2, lateral root second; LR3, lateral root third; MR, medial root; UN, ulnar nerve; MCNFA, musculocutaneous nerve of forearm.

• 

  Fig. 4 Photograph of formation of median nerve (MN) by four roots. LC, lateral cord; PC, posterior cord; MC, medial cord; AA, axillary artery; MCN, musculocutaneous nerve; LR, lateral root; MR, medial root; Ar1, first additional root; Ar2, second additional root; UN, ulnar nerve; RN, radial nerve.

• 

  Fig. 5 Photograph of formation of median nerve (MN) and communication with musculocutaneous nerve (MCN) (arrow). AA, axillary artery; LR, lateral root; MR, medial root; UN, ulnar nerve; PMn, pectoralis minor muscle cut end; BB, biceps brachii muscle; CB, coracobrachialis muscle.

Reference

References

1. Ghosh B, Parashar V, Gaur N, Thakur B, Yadav S. 2015; Variation in median nerve formation associated with anomalous higher origin of profunda brachi artery. Int J Recent Sci Res. 6:5654–6.

2. Datta AK. 2017. Essentials of human anatomy. 5th ed. Vol 3:Current Books International;Kolkata: p. 41.

3. Standring S. 2016. Gray's anatomy: the anatomical basis of clinical practice. 41st ed. Elsevier;Philadelphia: p. 781–3.

4. Taams KO. 1997; Martin-Gruber connections in South Africa. An anatomical study. J Hand Surg Br. 22:328–30. DOI: 10.1016/S0266-7681(97)80396-8. PMID: 9222911.

5. Drake RL, Vogl W, Mitchell AWM. 2005. Gray's anatomy for students. Elsevier/Churchill Livingstone;Philadelphia: p. 661–3.

6. Vollala VR, Raghunathan D, Rodrigues V. 2005; Nerve compressions in upper limb: a case report. Neuroanatomy. 4:35–6.

7. Gacek RR. 1990; Neck dissection injury of a brachial plexus anatomical variant. Arch Otolaryngol Head Neck Surg. 116:356–8. DOI: 10.1001/archotol.1990.01870030120023. PMID: 2306357.

8. Romanes GJ. 1986. Cunningham's manual of practical anatomy. 15th ed. Upper and lower limb. Volume 1:Oxford University Press;Oxford: p. 28–30. DOI: 10.1001/archotol.1990.01870030120023.

9. Gupta M, Goyal N, Harjeet . 2005; Anomalous communications in the branches of brachial plexus. J Anat Soc India. 54:22–5.

10. Budhiraja V, Rastogi R, Asthana AK. 2011; Anatomical variations of median nerve formation: embryological and clinical correlation. J Morphol Sci. 28:283–6.

11. Nayak S. 2007; Absence of musculocutaneous nerve associated with clinically important variations in the formation, course and distribution of the median nerve- a case report. Neuroanatomy. 6:49–50.

12. Uzun A, Bilgic S. 1999; Some variations in the formation of the brachial plexus in infants. Tr J Med Sci. 29:573–7.

13. Chauhan R, Roy TS. 2002; Communication between the median and musculocutaneous nerve - a case report. J Anat Soc India. 51:72–5.

14. Saeed M, Rufai AA. 2003; Median and musculocutaneous nerves: variant formation and distribution. Clin Anat. 16:453–7. DOI: 10.1002/ca.10096. PMID: 12903070.

15. Sontakke BR, Tarnekar AM, Waghmare JE, Ingole IV. 2011; An unusual case of asymmetrical formation and distribution of median nerve. Int J Anat Var. 4:57–60.

16. Pais D, Casal D, Santos A, O'Neill JG. 2010; A variation in the origin of the median nerve associated with an unusual origin of the deep brachial artery. J Morphol Sci. 27:35–8.

17. Uzun A, Seelig LL Jr. 2001; A variation in the formation of the median nerve: communicating branch between the musculocutaneous and median nerves in man. Folia Morphol (Warsz). 60:99–101. PMID: 11407150.

18. Haviarova Z, el Falougy HA, Killingerova A. 2001; Atypical course of the median nerve. Bratisl Lek Listy. 102:372–3. PMID: 11763668.

19. Pandey SK, Shukla VK. 2007; Anatomical variations of the cords of brachial plexus and the median nerve. Clin Anat. 20:150–6. DOI: 10.1002/ca.20365. PMID: 16795062.

20. Choi D, Rodríguez-Niedenführ M, Vázquez T, Parkin I, Sañudo JR. 2002; Patterns of connections between the musculocutaneous and median nerves in the axilla and arm. Clin Anat. 15:11–7. DOI: 10.1002/ca.1085. PMID: 11835538.

21. Yang ZX, Pho RW, Kour AK, Pereira BP. 1995; The musculocutaneous nerve and its branches to the biceps and brachialis muscles. J Hand Surg Am. 20:671–5. DOI: 10.1016/S0363-5023(05)80289-8. PMID: 7594300.

22. Larsen WJ. 1997. Human embryology. 2nd ed. Churchill Livingstone;New York: p. 311–39.

23. Brown MC, Hopkins WG, Keynes RI. 1991. Essentials of neural development. Cambridge University Press;Cambridge: p. 46–66.

24. Sanes DH, Reh TA, Harris WA. 2000. Development of the nervous system. Academic Press;San Diego: p. 189–97.