PCL5- nerves of the forearm,wrist and hands

The Main Nerves of the Forearm,wrist and hands

Median nerve

• This nerve enters the forearm with the brachial artery.
• It lies on the brachialis muscle and passes between the two heads of the pronator teres muscle, giving branches to both.
• Afterwards, it descends deep to the flexor digitorum superficialis muscle, closely attached by the muscle's facial sheath.

• Then is continues between the two flexor digitorum muscles.

• Near the wrist, it becomes superficial, passing between the tendons of the flexor digitorum superficialis and the flexor carpi ulnaris muscles, deep to the tendon of palmaris longus muscle.

• The median nerve enters the hand through the carpal tunnel, between the tendons of flexor digitorum superficialis and flexor carpi radialis.

• It supplies motor fibres to the 3 thenar muscles and the 1^st and 2^nd lumbrical muscles.
• Also provides sensation to skin of palmar and distal dorsal aspects of lateral 31/2 digits and adjacent palm

Branches of median nerve

1. Recurrent branch distribution

- abductor pollicis brevis,opponens pollicis,superficial head of flexor pollicis brevis

2. Lateral branch distribution

-1^st lumrical:skin of palmar and distal dorsal aspects of thumb and radial half of 2^nd digit

3. Medial branch distribution

-2^nd lumbrical, skin of plamr and distal dorsal aspects of adjacent sides of 2-4^th digits

4. palmar cutaneous distribution

-skin of central palm

The Ulnar Nerve

• This nerve passes posterior to the medial epicondyle of the humerus.
• It enters the forearm by passing between the two heads of the flexor carpi ulnaris muscle.
• It then descends deep to this muscle on the flexor digitorum profundus, where it accompanies the ulnar artery near the middle of the forearm.
• Then it passes on the medial side of this artery and the lateral side of the tendon of flexor carpi ulnaris.

• In the distal part of the forearm, the ulnar nerve become relatively superficial covered only by fascia and skin.

ULNAR NERVE BRANCHES

1. Palmar cutaneous distribution

-skin at base of medial palm overlying the medial carpals

2. dorsal branch distribution

- skin of medial aspects of dorsum of hand and proximal portions of little and medial half of ring finger.

3. Superficial branch distribution

-palmaris brevis and sensation to the skin of the palmar and distal dorsal aspects of digit 5 and of the medial side of digit 4 and proximal portion of palm

4. deep branch distribution

-hypothenar muscles,lumbricals of digits 4 and 5, all interossei,adductor pollicis and deep head of flexor pollicis brevis

The Radial Nerve

• The radial nerve descends in the arm between the brachialis and brachioradialis muscles.
• It crosses the anterior aspect of the lateral epicondyle.
• Soon after it enters the forearm, it divides into superficial and deep branches.

Superficial branch distribution

-skin of lateral half of dorsal aspects of the hand and thumb and the proximal portions of the dorsal aspects of digits 2 and 3 and of the lateral half of digit 4