Variation in the branching pattern of posterior cord of brachial plexus

During the routine dissection in the department of Anatomy, KMC, Manipal, we found a rare and unreported variation in the branching pattern of the posterior cord of brachial plexus. Normally, a single posterior cord is formed by the union of posterior divisions of the trunks of the brachial plexus. All the branches of the posterior cord arise from this single cord. Here we report that, after formation of posterior cord, the cord has divided again into two roots, and enclosed the subscapular artery. Then, these two roots fused to continue as radial nerve. In this report, we also describe the variations in the branching pattern of the posterior cord and clinical relevance of this variation.