median nerve

Last reviewed 01/2018

The median nerve is formed by the union of the lateral and medial cords of the brachial plexus and carries fibres derived from the 6th, 7th and 8th cervical and the 1st thoracic spinal segments. It lies close to the brachial artery in the upper arm and passes under the transverse carpal ligament as it approaches the palm of the hand.

It carries both motor and sensory fibres:

  • motor:
    • supplies all the muscles on the front of the forearm except flexor carpi ulnaris and the ulnar half of flexor digitorum profundus
    • four small muscles of the hand are supplied the median nerve; the mnemonic LOAF is useful:
      • lateral two lumbricals
      • opponens pollicis
      • abductor pollicis brevis
      • flexor pollicis brevis

  • sensory - skin of hand - palmar aspect of the radial three and one half fingers and nail beds of radial three and one half fingers