Chapter 41 - Anatomy of the Median Nerve and Its Branches

Abstract

Thorough knowledge of median nerve anatomy is of utmost importance to diagnose and treat injuries and entrapment neuropathies affecting this nerve and its major branches in the upper extremity. The median nerve enters the axillary outlet with the axillary/brachial artery as a neurovascular bundle, and travels distally in the arm within the median bicipital groove. In the cubital fossa, the median nerve traverses the bicipital aponeurosis, pronator teres, and flexor digitorum superficialis, where the anterior interosseous branch enters deeply into the forearm. The main trunk of the median nerve travels distally in the forearm, providing a pure cutaneous sensory palmar branch, and passes underneath the flexor retinaculum through the carpal tunnel into the hand. The first branch in the hand is generally the thenar motor branch, which bifurcates into radial and ulnar divisions that eventually further bifurcate into the common digital nerves that subsequently divide into proper digital nerves.