Unilateral multiple variations of the brachial plexus

Brachial plexus variations were encountered in the right upper limb of an adult mate cadaver during the routine dissection course for undergraduate teaching at the Department of Anatomy, College of Medicine, King Saud University. The ventral rami of C4 and T2 were shared in the formation of the variant brachial plexus. The anterior and posterior divisions of the upper trunk fused with the middle trunk to form a single unit, which divided into anterior and posterior subdivisions. The posterior subdivision joined the posterior division of the lower trunk, forming the posterior cord and giving off the usual branches, while the anterior subdivision joined the anterior division of the lower trunk to form the anterior cord. No lateral or medial cords were found in this cadaver; only anterior and posterior cords, according to their relationship with the second part of the axillary artery. We also observed a medial pectoral nerve with two routes and the absence of a musculocutaneous nerve.