Abductor pollicis longus muscle
| Abductor pollicis longus muscle |
|---|
|
| Hand muscles of man |
| origin |
| Posterior surface of the radius and ulna , interosseous membrane |
| approach |
| First metacarpal and basal phalanx of the thumb |
| function |
| Splaying the thumb |
| Innervation |
| Radial nerve of the brachial plexus |
| Spinal segments |
| C7, C8 |
The abductor pollicis longus muscle ( Latin for "long thumb spreader" or "long thumb puller") is an extensor muscle in the deep layer of the forearm . The skeletal muscle is responsible for the spreading ( abduction ) of the thumb .
Its insertion tendon runs together with that of the extensor pollicis brevis muscle through the first tendon sheath compartment of the extensor retinaculum .