Concomitant variations of the brachial plexus and third part of axillary artery in a middle aged female cadaver: an original case report

Introduction The brachial plexus is a complex network of nerves extending from the neck to axilla supplying motor sensory and sympathetic fibers to the upper extremity and superficial muscles of the back. It is formed by the fusion of the anterior primary rami of the C5, C6, C7, C8, and T1 spinal nerves, with occasional communications from C4 and T2 making it either pre-fixed or post-fixed, respectively. The C5 and C6 form the upper trunk, the C7 continues as the middle trunk and the C8 and T1 join to form the lower trunk. The anterior divisions of the upper and middle trunks form the lateral cord, the lower trunk continues as the medial cord, and the posterior divisions of all three trunks form the posterior cord, which gives terminal branches at the lower border of pectoralis minor, the various branches that form the peripheral nerves of the upper limb [1]. The brachial plexus is divided into supraclavicular and infraclavicular parts. The roots and the trunk lie in the neck, the divisions behind the clavicle, cords and branches in the axilla [1]. The various branches of the plexus are derived from the roots, trunks and cords but none from the divisions [2]. The cords of the brachial plexus, i.e. the lateral, medial and posterior cords lie lateral, medial and posterior respectively, to the second part axillary artery. The axillary artery gives three separate branches in its third part which are the subscapular artery, anterior and posterior humeral circumflex arteries.