Comparative supply of radial nerve median nerve ulnar nerve
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radial median ulnar nerve motor sensory supply anatomy
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Comparative supply: radial, median, and ulnar nerves
| Feature | Radial nerve | Median nerve | Ulnar nerve |
|---|---|---|---|
| Roots | C5-T1 | C5-T1 | C8-T1, sometimes C7 |
| Brachial plexus origin | Posterior cord | Lateral and medial cords | Medial cord |
| Main forearm compartment | Posterior compartment | Most of anterior compartment | Medial part of anterior compartment |
| Main action | Extension | Pronation, wrist/finger/thumb flexion, thumb opposition | Finger abduction/adduction and fine intrinsic hand movements |
1. Motor supply
| Nerve | Forearm muscles | Hand muscles |
|---|---|---|
| Radial | Triceps, anconeus, brachioradialis, ECRL; via posterior interosseous nerve supplies the remaining wrist, finger, and thumb extensors | No intrinsic hand muscles |
| Median | Most flexor-pronator muscles: pronator teres, FCR, palmaris longus, FDS. Its anterior interosseous branch supplies FPL, pronator quadratus, and lateral half of FDP to index and middle fingers. | Thenar muscles: abductor pollicis brevis, opponens pollicis, superficial head of flexor pollicis brevis; also 1st and 2nd lumbricals |
| Ulnar | Flexor carpi ulnaris and medial half of FDP to ring and little fingers | All other intrinsic hand muscles: interossei, adductor pollicis, hypothenar muscles, deep head of FPB, 3rd and 4th lumbricals |
Hand mnemonic: Median nerve supplies LOAF:
Lateral 2 lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis superficial head.
All other intrinsic hand muscles are mainly ulnar supplied. This division is described in Gray's Anatomy for Students, which also notes that radial nerve contributes sensory but not intrinsic motor supply to the hand.
Lateral 2 lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis superficial head.
All other intrinsic hand muscles are mainly ulnar supplied. This division is described in Gray's Anatomy for Students, which also notes that radial nerve contributes sensory but not intrinsic motor supply to the hand.
2. Cutaneous sensory supply
| Nerve | Sensory territory |
|---|---|
| Radial | Posterior arm and forearm, dorsolateral hand, dorsal thumb, index, middle, and lateral half of ring finger, mainly proximal dorsal portions. First dorsal web space between thumb and index is the key autonomous zone. |
| Median | Lateral palm and palmar surface of lateral 3½ digits: thumb, index, middle, and lateral half of ring finger. Also supplies dorsal distal phalanges/nail beds of these digits. Tip/pulp of index finger is a useful autonomous zone. |
| Ulnar | Medial hand and medial 1½ digits: little finger and medial half of ring finger, on both palmar and dorsal surfaces. Tip of little finger is a useful autonomous zone. |
The median and ulnar nerves supply the volar hand and digits, while the superficial radial nerve supplies the dorsoradial hand, as summarized in this hand innervation overview.
3. Key clinical examination
| Nerve | Quick motor test | Quick sensory test | Typical palsy sign |
|---|---|---|---|
| Radial | Extend wrist and fingers against resistance | First dorsal web space | Wrist drop |
| Median | Thumb opposition, make an “OK” sign | Index fingertip | Thenar wasting, loss of opposition, ape thumb in severe lesion |
| Ulnar | Abduct/adduct fingers, paper grip test | Little-finger tip | Clawing of ring/little fingers, interosseous wasting, positive Froment sign |
One-line summary
- Radial: the extensor nerve, sensory to dorsolateral hand.
- Median: the precision and opposition nerve, sensory to lateral 3½ palmar digits.
- Ulnar: the intrinsic hand nerve, sensory to medial 1½ digits.
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