Absence of left musculocutaneous nerve & variant origin of left ulnar nerve-a case report

The brachial plexus is constituted by the ventral rami of spinal cervical nerves including C5-C8 and the first thoracic spinal nerve. There are five stages in the brachial plexus-root, trunk, division, cord and branch stages. The branches of the lateral cord are the lateral pectoral nerve, the musculocutaneous nerve and the lateral root of median nerve. The branches of the medial cord are the medial pectoral nerve, the medial cutaneous nerves of arm and forearm, the median and the ulnar nerves. The branches of the posterior cord are the upper and lower subscapular nerves, the nerve to latissimus dorsi, the axillary and the radial nerves.1