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Forearm & Hand Muscles
The flexor and pronator muscles of the front of the forearm, the extensor and supinator muscles of the back, and the small intrinsic muscles of the hand — thenar, hypothenar, lumbricals and interossei — that give the fingers their fine control.
This page lists all 30 of them in the reference. Open any muscle for its origin, insertion, actions, nerve supply and clinical pearl.
| Muscle | Main actions | Nerve supply |
|---|---|---|
| Abductor Digiti Minimi (Hand) | Spreads the little finger away from the ring finger | Ulnar nerve, deep branch (C8–T1) |
| Abductor Pollicis Brevis | Moves the thumb away from the palm, at right angles to it (palmar abduction) | Median nerve, recurrent branch (C8–T1) |
| Abductor Pollicis Longus | Moves the thumb away from the palm in its plane (abduction at the wrist joint of the thumb); Helps straighten the wrist toward the thumb side | Posterior interosseous nerve (C7–C8) |
| Adductor Pollicis | Pulls the thumb in toward the palm (adduction); Powers pinch grip | Ulnar nerve, deep branch (C8–T1) |
| Dorsal Interossei (Hand) | Spread the fingers apart (abduction) — 'DAB'; Help bend the knuckles while straightening the finger joints | Ulnar nerve, deep branch (C8–T1) |
| Extensor Carpi Radialis Brevis | Straightens the wrist (extension) | Posterior interosseous nerve (radial, C7–C8) |
| Extensor Carpi Radialis Longus | Straightens the wrist (extension); Tilts the hand toward the thumb side (radial deviation) | Radial nerve (C6–C7) |
| Extensor Carpi Ulnaris | Straightens the wrist (extension); Tilts the hand toward the little-finger side (ulnar deviation) | Posterior interosseous nerve (C7–C8) |
| Extensor Digiti Minimi | Straightens the little finger | Posterior interosseous nerve (C7–C8) |
| Extensor Digitorum | Straightens the fingers at the knuckles (MCP joints); Helps straighten the wrist | Posterior interosseous nerve (C7–C8) |
| Extensor Indicis | Straightens the index finger independently (pointing) | Posterior interosseous nerve (C7–C8) |
| Extensor Pollicis Brevis | Straightens the thumb at the knuckle (MCP joint); Helps move the thumb away from the palm | Posterior interosseous nerve (C7–C8) |
| Extensor Pollicis Longus | Straightens the thumb tip; Pulls the thumb back in line with the hand (reposition) | Posterior interosseous nerve (C7–C8) |
| Flexor Carpi Radialis | Bends the wrist forward (flexion); Tilts the hand toward the thumb side (radial deviation) | Median nerve (C6–C7) |
| Flexor Carpi Ulnaris | Bends the wrist forward (flexion); Tilts the hand toward the little-finger side (ulnar deviation) | Ulnar nerve (C7–C8) |
| Flexor Digiti Minimi Brevis (Hand) | Bends the little finger at the knuckle (MCP joint) | Ulnar nerve, deep branch (C8–T1) |
| Flexor Digitorum Profundus | Bends the fingertips (DIP joints) — the only muscle that does; Helps bend the other finger joints and the wrist | Median nerve (index and middle) and ulnar nerve (ring and little), C8–T1 |
| Flexor Digitorum Superficialis | Bends the fingers at the middle joints (PIP); Helps bend the fingers at the knuckles and the wrist | Median nerve (C8–T1) |
| Flexor Pollicis Brevis | Bends the thumb at the knuckle (MCP joint) | Median nerve (recurrent branch) and ulnar nerve (deep branch) |
| Flexor Pollicis Longus | Bends the thumb tip (interphalangeal joint); Helps bend the other thumb joints | Anterior interosseous nerve (median, C8–T1) |
| Interossei and Lumbricals (Intrinsic Group) | Fine control of finger posture — bend at the knuckle, straighten beyond it | Mainly ulnar nerve deep branch; lateral lumbricals median (C8–T1) |
| Lumbricals (Hand) | Bend the fingers at the knuckles while straightening the middle and tip joints — the 'intrinsic plus' position | Median nerve (1st–2nd) and ulnar nerve deep branch (3rd–4th), C8–T1 |
| Opponens Digiti Minimi | Cups the palm by drawing the fifth metacarpal forward | Ulnar nerve, deep branch (C8–T1) |
| Opponens Pollicis | Brings the thumb across the palm to meet the fingers (opposition) | Median nerve, recurrent branch (C8–T1) |
| Palmar Interossei (Hand) | Bring the fingers together toward the middle finger (adduction) — 'PAD' | Ulnar nerve, deep branch (C8–T1) |
| Palmaris Brevis | Wrinkles the skin over the hypothenar eminence; Deepens the hollow of the palm | Ulnar nerve, superficial branch |
| Palmaris Longus | Bends the wrist weakly; Tenses the palm's fascia | Median nerve (C7–C8) |
| Pronator Quadratus | Turns the forearm palm-down (the main pronator for slow, unloaded movement) | Anterior interosseous nerve (median, C8–T1) |
| Pronator Teres | Turns the forearm palm-down (pronation); Helps bend the elbow | Median nerve (C6–C7) |
| Supinator | Turns the forearm palm-up (supination) when the elbow is straight | Posterior interosseous nerve (C6–C7) |
Please note: This page is an anatomy education summary for students and curious readers, not medical advice. Attachment points are given in their classic short form; individual anatomy varies, and detailed dissection-level descriptions belong in an anatomy atlas.