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
    • medial root: medial cord of the brachial plexus
  • 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: palmar aspect of the thumb, index, middle and radial half of the ring fingers
Origin

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.

Course

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 adjacently to the brachial artery before entering the cubital fossa.

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

The median nerve enters the forearm between the two heads of pronator teres muscle and gives off the anterior interosseous nerve. It courses towards the wrist with the ulnar nerve and ulnar vessels (deep to flexor digitorum superficialis) and enters the hand through the carpal tunnel (the only nerve to traverse the carpal tunnel), passes deep to the flexor retinaculum at the wrist. On entering the palm, it gives off motor and cutaneous branches.

Branches
Upper limb anatomy
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Article information

rID: 21858
Section: Anatomy
Tags: cases, nerve
Synonyms or Alternate Spellings:

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Cases and figures

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    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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    Case 1: high division (variant anatomy)
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