Median Nerve, N463 Notes, Anatomy, Upper Limb, Neurovasculature

Branches from the medial and lateral cords: median nerve (Roots C5, C6, C7, C8, & T1)

1. Is formed by heads from both the medial and lateral cords.
2. Runs down the anteromedial aspect of the arm but does not branch in the brachium. Continues down the arm to enter the forearm with the brachial artery.
3. The median nerve is the only nerve that passes through the carpal tunnel, where it may be compressed to cause carpal tunnel syndrome. 
4. Articular branch to the Elbow
5. Two branches in the forearm:
   • anterior interosseous branch 
   • courses with the anterior interosseous artery and 
   • innervates all the muscles of the anterior compartment of the forearm except the flexor carpi ulnaris and the medial (ulnar) half of flexor digitorum profundus. 
   • It ends with its innervation of pronator quadratus.
   • palmar cutaneous branch of the median nerve arises at the distal part of the forearm. 
   • It supplies sensory innervation to the lateral aspect of the skin of the palm (but not the digits).

Arm - vascular sympathetic branches to the wall of the Brachial artery.

Forearm

• It innervates all of the flexors in the forearm except flexor carpi ulnaris and that part of flexor digitorum profundus that supplies the medial two digits. The latter two muscles are supplied by the ulnar nerve (specifically the Muscular branches of ulnar nerve).
• The main portion of the median nerve supplies the following muscles:

1. Superficial group:

1. Pronator teres
2. Flexor carpi radialis
3. Palmaris longus

1. Intermediate group:

• Flexor digitorum superficialis muscle

1. The anterior interosseus branch of the median nerve supplies the following muscles:

Deep group:

• Flexor digitorum profundus (only the lateral half)
• Flexor pollicis longus
• Pronator quadratus

[edit]Hand

1. motor innervation to the 1st and 2nd lumbrical muscles. 
2. muscles of the thenar eminence by a recurrent thenar branch. The rest of the intrinsic muscles of the hand are supplied by the ulnar nerve.

The median nerve innervates the skin of the palmar side of the thumb, the index and middle finger, half the ring finger, and the nail bed of these fingers. The lateral part of the palm is supplied by the palmar cutaneous branch of the median nerve, which leaves the nerve proximal to the wrist creases. This palmar cutaneous branch travels in a separate fascial groove adjacent to the flexor carpi radialis and then superficial to the flexor retinaculum. It is therefore spared in carpal tunnel syndrome.

The muscles of the hand supplied by the median nerve can be remembered using the mnemonic, "LOAF" for 

1. Lumbricals 1 & 2, 
2. Opponens pollicis, 
3. Abductor pollicis brevis and 
4. Flexor pollicis brevis. Superficial Head only - Deep Head supplied by the Ulnar Nerve

Median Nerve, N463 Notes, Anatomy, Upper Limb, Neurovasculature