Nerve Supply to the Hand

The nerve supply of the anterior forearm and hand muscles is mainly by 2 nerves, namely, the Median nerve and the Ulnar nerve. In the anterior forearm, most of the muscles are supplied by the median nerve, and few are supplied by the ulnar nerve. In hand, most of the muscles are supplied by the ulnar nerve, and few are supplied by the median nerve. There are 8 muscles in the anterior forearm. Out of the 8 muscles, 1 ½ muscles that are supplied by the ulnar nerve are the Flexor carpi ulnaris and the medial half of the flexor digitorum profundus. Rest all muscles in the anterior forearm by the median nerve. 

In the Hand ulnar nerve supplies 15 muscles, including Hypothenar muscles, Lumbricals -3 & 4, and all 8 interossei muscles, whereas In the Hand, the median nerve supplies 5 muscles they are Lumbricals -1 & 2, Abductor pollicis brevis, and 2 hybrid muscles:  opponens pollicis and flexor pollicis brevis. The hybrid muscles are supplied by both the ulnar and median nerve.

Ulnar and Median Nerve in Axilla Region

The medial cord of the brachial plexus continues as the ulnar nerve. Which supplies few muscles in anterior forearm and most muscles in hand. The Root value of ulnar nerve- C7, C8 and T1. The medial cord and lateral cord of the brachial plexus contribute to the medial nerve, which supplies most muscles in the arm and forearm and a few muscles in the hand. The Root value of median nerve is C5, C6, C7, C8 and T1.

Ulnar Nerve C7-C8-T1

Ulnar Nerve Supply in the Forearm

The Anterior compartment of the forearm supplies 112 muscles

• Flexor carpi ulnaris
• Medial half of flexor digitorum profundus

The main action of ulnar nerve in the forearm is to weakly Flex wrist and supplies digits 4 and 5. 

Ulnar Nerve Supply in The Hand

The ulnar nerve supplies Hypothenar muscles in hand. The 8 palmar and Dorsal  Interossei muscles are also supplied by the ulnar nerve. The ulnar nerve Abducts digits 2 to 5 of dorsal interossei group (can be remembered by the mneumonic DAB). The Palmar interossei group is Adducted by the ulnar nerve’s action. This adduction is seen in the digits 2-5 (can be remembered by the mneumonic PAD). the ulnar nerve also Assists Lumbricals in MCP flexion and IP extension in the digits 2-5.

In the hand ulnar nerve also supplies the Lumbricals, Digits 4 & 5. It causes Flexion in MCP and it extends PIP & DIP joints of digits 4 and 5. Adductor pollicis and its two Hybrid muscles, Flexor pollicis brevis and opponens pollicis are also innervated by the ulnar nerve and it causes Adduction of the thumb.

Median Nerve C5-T1

Median Nerve Supply in the Forearm

The Anterior compartments all muscles except for 1 ½ muscles that are supplied by the ulnar nerve are supplied by the median nerve. Deep muscles of anterior forearm supplied by AIN- anterior interosseous nerve which is the deep branch of median nerve. AIN supplies 2 ½ muscles. 

• Pronator quadratus 
• Flexor pollicis longus 
• Lateral half of the flexor digitorum profundus 

The main trunch of Median nerve also supplies superficial muscles. Such as:

• Pronator teres
• Flexor carpi radialis 
• Palmaris longus
• Flexor digitorum superficialis

This action of median nerves on the forearm causes flexion of the wrist and all digits. It also causes pronation in the wrist.

Median Nerve Supply in the Hand

The median nerve supplies the Abductor pollicis brevis and the 2 hybrid muscles, opponens pollicis and flexor pollicis brevis. It causes the Opposition of thumb. The median nerve supplies the Lumbricals, Digits 2 and 3. Median nerve causes Flexion of  metacarpophalangeal (MCP), extension of the interphalangeal PIP and  DIP joints of digit 2 and 3.

Cutaneous Supply of Hand

This has been asked in recent competitive exams time and time again. It is highly suggestive that video lecture is also watched with this to get a clearer picture of the cutaneous supply of the hand.  

• ULNAR NERVE:  Medial 1 ½ fingers anteriorly & posteriorly, skin over hypothenar area and dorsum of hand 
• MEDIAL NERVE: 3 ½ finger anteriorly & 3 1/2 nail beds posteriorly, thenar eminence and skin over palm
• RADIAL NERVE: 3 ½ of fingers except nail beds of dorsum of hand

Frequently Asked Questions

Q. Which of the following muscle has dual nerve supply

1. Flexor digitorum profundus
2. Interossei
3. Palmaris brevis
4. Flexor carpi ulnaris

Answer: Flexor digitorum profundus

Q: What nerve supplies the Medial 1 ½ fingers anteriorly & posteriorly along with the skin over hypothenar area and dorsum of hand?

Answer: Ulnar Nerve

Q: What nerve supplies the 3 ½ finger anteriorly & 3 1/2 nail beds posteriorly along with the thenar eminence and skin over palm?

Answer: Medial nerve

Q: What nerve supplies the 3 ½ of fingers except nail beds of dorsum of hand?

Answer: Radial Nerve

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