Two cord stage in the infraclavicular part of the brachial plexus

Anatomical variations in the formation, course and distribution of brachial plexus are reported in the literature. We encountered a brachial plexus with two cords – anterior and posterior instead of lateral, medial and posterior cords which were present lateral to axillary artery during routine dissection of embalmed adult cadaver in the left upper limb. The anterior cord was giving off the branches of the lateral and medial cord. The posterior cord was giving off the radial and axillary nerves. The clinical significance and the embryological reasons are discussed.