A rare coexistence of axillo - brachial neurovascular variations with embryological review

The axillary neurovascular structures are one of the potential anatomical fields to show variations in many ways. The axillary artery gets divided in three parts by the fore lying pectoralis minor and provides the superior thoracic artery from first part, thoraco-acromial artery, lateral thoracic artery from second part and the third part gives anterior circumflex humeral, posterior circumflex humeral and subscapular arteries. After the distal border of teres major the axillary artery is continued in arm as brachial artery, from which the branches in the arm get distributed. To form the median nerve trunk from lateral (C6,7) and medial (C8, T1) cords of brachial plexus the two roots of median nerve emerge and unite embracing the third part of axillary artery, either anterior or lateral to it. The lateral root often being smaller than medial one, the median nerve usually passes lateral to axillary artery and continues in upper arm as lateral to brachial artery [1]. On the other hand the musculocutaneous nerve (C5,6,7) initially accompanies the third part of the axillary artery and pierces the coracobrachialis muscle after supplying it. Next it appears in between biceps brachii and brachialis, supplies them and just below the elbow it pierces the deep fascia lateral to the tendon of biceps brachii and extends further downward as the lateral cutaneous nerve of the forearm [2]. Case Report