Unusual Course of Median Nerve in the Arm and its Clinical Relevance - A Cadaveric Study

The median nerve (C5,C6, C7,C8 and T1) supplies most of the muscles of flexor compartments of the forearm and the muscles of the thenar eminence in the hand. In the arm, at the level of insertion of coracobrachialis, usually, the median nerve crosses from lateral to medial in front of the brachial artery and accompanies it along the medial side. Here we present this rare and interesting case report of an important variation in the course and relation of the median nerve in the arm. During routine dissection of a 70-year-old male cadaver allotted for the undergraduate students of the 2020- 2021 batch in the department of anatomy, Sree Mookambika Institute of Medical Sciences, Kulasekharam, we found that the formation of the median nerve was normal, but at the level of insertion of coracobrachialis the median nerve crossing the brachial artery from lateral to medial side passing behind the brachial artery and accompanies along the medial side, the remaining course and relation of the median nerve is normal. The opposite upper limb was also dissected to find out any variation in its course and relation but was found to be normal. The unusual course of median nerve passing behind the brachial artery while crossing from lateral to medial side at the level of insertion of coracobrachialis should be kept in mind while performing surgeries, reduction of fractures and nerve block in the middle of the arm.