Anat Cell Biol.  2024 Mar;57(1):18-24. 10.5115/acb.23.229.

The anatomical variations of median nerve in Shiraz, Iran

• Moasses Z
• Aryan A
• Hassanpour-Dehnavi A
• Zarenezhad M
• Dorodchi A

• KMID: 2554237
• DOI: http://doi.org/10.5115/acb.23.229

Abstract

The origin and distribution of median nerve varies among the different individuals. The median nerve variations in axillary region were reported by many authors previously. Understanding of these variations is especially necessary for clinicians to prevent iatrogenic nerve damage. The current work aimed to evaluate the possible anatomical variations of median nerve in the axillary region in a sample of the Iranian cadavers (Shiraz, Fars). We dissected 26 upper limbs from 13 male cadavers to investigate the different variations of median and musculocutaneous nerves according to Venieratos and Anagnostopoulou classification. In 23.07% of specimens (n=6), the medial root united with 2 lateral roots and formed the median nerve proximal to the coracobrachialis muscle. In one case, a communicating branch separated from the musculocutaneous nerve distal to the coracobrachialis and connected to the median nerve in upper arm. Our results suggest that there are anatomical variations of the median nerve in terms of its origin and its communication with the musculocutaneous nerve in the population of southern Iran. The anatomical knowledge of the median nerve variations is important for clinicians to improve patient health outcome. Theses variations of the median nerve should be considered during surgical procedures of the axillary region and nerve block of the infra clavicular part of the brachial plexus.

Keyword

Brachial plexus; Median nerve; Musculocutaneous nerve; Anatomic variation; Axilla

Figure

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  Fig. 1 (A) Schematic representation of brachial plexus, (B) typical formation of median nerve and (C) three different atypical communications between median and musculocutaneous nerves. MN, median nerve; LR, lateral root (1 and 2); MCN, musculocutaneous nerve; CRDs, cords; LC, lateral cord; DIVs, divisions; TNKs, trunks; RTs, roots; MR, medial root; UN, ulnar nerve; MC, medial cord; PC, posterior cord; PMi, pectoralis minor; CP, coracoid process; AA, axillary artery; Dt, deltoid muscle; CB, coracobrachialis; PM, pectoralis major; SB, short head of biceps; LB, long head of biceps; SJ, shoulder joint; LCF, lateral cutaneous nerve of forearm; COM, communicating branch; NCB, nerve to coracobrachialis.

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  Fig. 2 The normal distribution of branches from lateral and medial cords in right axillary region. PMi, pectoralis minor; LC, lateral cord; MCN, musculocutaneous nerve; PM, pectoralis major; LR, lateral root of median nerve; MR, medial root of median nerve; CB, coracobrachialis; MN, median nerve; BA, brachial artery; AA, axillary artery; AV, axillary vein; MC, medial cord; MCF, medial cutaneous nerve of forearm; UN, ulnar nerve; LN, axillary lymph nodes.

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  Fig. 3 (A–D) Photographs depicting the 2 lateral roots of median nerve in case 1, 3, 4, and 5. LR1, first lateral root; LR2, second lateral root; MN, median nerve; AA, axillary artery; Pmi, pectoralis minor muscle; MC, medial cord; MR, medial root; MCF, medial cutaneous nerve of forearm; AV, axillary vein; UN, ulnar nerve; LC, lateral cord; PM, pectoralis major muscle; MCN, musculocutaneous nerve; CB, coracobrachialis muscle; RN, radial nerve.

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  Fig. 4 (A) Dissection of right and (B) left axillary regions in case 2. COM, communicating branch; BM, biceps muscle; CB, coracobrachialis muscle; PM, pectoralis major muscle; MCN, musculocutaneous nerve; MN, median nerve; MCF, medial cutaneous nerve of forearm; AA, axillary artery; LC, lateral cord; LR, lateral root (1 and 2); MC, medial cord; AV, axillary vein; MR, medial root; UN, ulnar nerve.

Reference

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