Expansion
Flexor pollicis longus, lateral half of flexor digitorum profundus and pronator quadratus
Expansion
The anterior interosseous nerve, a branch of the median nerve, supplies:
- Flexor pollicis longus
- Lateral half of flexor digitorum profundus (index and middle fingers)
- Pronator quadratus
Because these flex the tips of the thumb and index finger, injury produces a weak pinch and an abnormal, flattened “OK” sign with no sensory loss.