The median nerve is one of the five main nerves originating from the brachial plexus and provides motor and sensory innervation to parts of the forearm and hand. 

  • origin
    • lateral root: lateral cord of the brachial plexus (C5, C6, C7)
    • medial root: medial cord of the brachial plexus (C8, T1)
  • course: laterally to the axillary artery, descends in the arm between biceps brachii and triceps brachii muscles, courses through the forearm with the ulna nerve and vessels before entering the carpal tunnel to the hand
  • major branches: anterior interosseous nerve, palmar cutaneous branch, motor branch in the hand
  • motor supply: flexor compartment of the forearm, thenar and intrinsic hand muscles
  • sensory supply: skin over thenar eminence, palmar aspect of the thumb, index, middle finger and radial half of the ring finger

The median nerve is formed from a lateral root from the lateral cord and a medial root from the medial cord of the brachial plexus. It forms from nerve roots originating at C5-T1.

In the axilla, the median nerve lies lateral to the axillary artery. It enters the arm from axilla at the inferior margin of the teres major muscle and descends medially between biceps brachii and triceps brachii. In the arm, the median nerve courses laterally to the brachial artery and then crosses it, usually anteriorly, from lateral to medial. It lies initially on coracobrachialis, then brachialis. 

In the cubital fossa, the median nerve lies medial to the brachial artery and the biceps brachii tendon.

The median nerve leaves the bicipital aponeurosis and enters the forearm between the two heads of pronator teres muscle and gives off the anterior interosseous nerve. It courses towards the wrist deep to flexor digitorum superficialis and superficial to flexor digitorum profundus muscle. It emerges lateral to the flexor digitorum superficialis about 5 cm proximal to the wrist (giving off the palmar cutaneous branch) and enters the hand through the carpal tunnel (the only nerve to traverse the carpal tunnel), passing deep to the flexor retinaculum at the wrist. On entering the palm, it gives off motor and cutaneous branches.

Anatomy: Upper limb

Anatomy: Upper limb

Article information

rID: 21858
Section: Anatomy
Tag: nerve
Synonyms or Alternate Spellings:

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Cases and figures

  • Figure 1: median nerve
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  • Figure 2: brachial plexus
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  • Figure 3: carpal tunnel diagram
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  • Figure 4: anterior arm anatomy (Gray's illustration)
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  • Figure 5: anterior forearm deep anatomy (Gray's illustration)
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  • Figure 6: anterior forearm anatomy (Gray's illustration)
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  • Figure 7: cubital fossa (diagram)
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  • Figure 8: carpal tunnel syndrome
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  • Case 1: high division (variant anatomy)
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