Median Nerve

Question 1

What are the nerve roots

Answer 1

Nerve roots: C6 – T1. (Also contains fibres from C5 in some individuals).

Question 2

What are the motor functions?

Answer 2

Innervates the flexor muscles in the anterior compartment of the forearm (except the flexor carpi ulnaris and part of the flexor digitorum profundus, innervated by the ulnar nerve). Also supplies innervation to the thenar muscles and lateral two lumbricals in the hand.

Question 3

What are the sensory functions?

Answer 3

Gives rise to the palmar cutaneous branch, which innervates the lateral part of the palm, and the digital cutaneous branch, which innervates the lateral three and a half fingers on the anterior (palmar) surface of the hand.

Question 4

What is the anatomical course>

Answer 4

• derived from the medial and lateral cords of the brachial plexus. It contains fibres from all five roots (C5-T1).
• After originating from the brachial plexus in the axilla, the median nerve descends down the arm, initially lateral to the brachial artery. Halfway down the arm, the nerve crosses over the brachial artery, and becomes situated medially. The median nerve enters the anterior compartment of the forearm via the cubital fossa.
• In the forearm, the nerve travels between the flexor digitorum profundus and flexor digitorum superficialis muscles. The median nerve gives rise to two major branches in the forearm:

Anterior interosseous nerve – Supplies the deep muscles in the anterior forearm.

Palmar cutaneous nerve – Innervates the skin of the lateral palm.

The median nerve enters the hand via the carpal tunnel, where it terminates by dividing into two branches:

Recurrent branch – Innervates the thenar muscles.

Palmar digital branch – Innervates the palmar surface and fingertips of the lateral three and half digits. Also innervates the lateral two lumbrical muscles.