Anomalous Branching Pattern of Lateral Cord of Brachial Plexus

Abstract

During routine dissection, an unusual formation of median nerve was detected in the right upper limb of a 55 year old male cadaver. The median nerve had an additional contribution from lateral cord. The two branches of the lateral cord designated as upper and the lower branches were observed at different levels. The upper branch was in close contact with the third part of the axillary artery and it crossed the vessel anteriorly to unite with a branch of the medial cord to form the median nerve. The median nerve thus formed was related medially to the axillary artery (instead of the normal position of being anterolateral). The median nerve descended below and was joined by an additional lower branch from the lateral cord. Interestingly, the ulnar nerve which arose from the medial cord, descended below and was joined within its fascial sheath by the medial cutaneous nerve of the forearm The presence of such an additional branch from the lateral cord contributing to the formation of median nerve and its unusual relation of being medial to the axillary artery may be of immense clinical interest to neurologists diagnosing nerve lesions and surgeons who are exposed to the topographical anatomy of the neural structures during radical neck dissection. The additional branch of the lateral cord may compress upon the axillary artery to cause vascular insufficiency