Median Nerve:Course & Innervation

Median Nerve:

  • The median nerve originates from lateral and medial cords of the brachial plexus
  • Lateral root arises from the anterior divisions of superior and middle trunks, has contributions from ventral roots of C5-C7
  • Medial root arises from the anterior division of inferior trunk and has contributions from ventral roots of C8-T1
  • It is one of the five main nerves originating from the brachial plexus.course of the median nerve


Course of the Median Nerve

  • Median nerve continues down the arm with brachial artery, when it initially lies lateral to the artery, and later crosses over to lie medial to it around halfway down the arm
  • Next, it passes within medial part of the antecubital fossa within the two heads of the pronator teres muscle
  • Then it goes through anterior forearm within flexor digitorum superficialis and flexor digitorum profundus muscles and performs three branches:
    Anterior interosseous nerve – descends simultaneously the anterior interosseous membrane with the anterior interosseous artery
    Deep branch – penetrates into hand through the carpal tunnel beneath flexor retinaculum of the wrist, within the flexor carpi radialis and the flexor digitorum superficialis tendons
    Superficial/palmar cutaneous branch – while arises just before the wrist and pierces carpal ligament to penetrate the carpal tunnel – this nerve is therefore not affected by carpal tunnel syndrome

Sensory Supply of the Median Nerve

  •  Median nerve does not provide any sensory innervation to the upper arm
  • Skin over the thenar eminence
  • The lateral ⅔ palm of the hand
  • The palmar aspect of lateral 3½ fingers
  • The dorsal fingertips of lateral 3½ fingers (thumb, index, middle and half of the ring finger)

Motor Supply of the Median Nerve

Common Median nerve injuries