MSK - Posterior Forearm Muscles (Deep) Flashcards
What are the FIVE deep muscles of the posterior forearm?
- Supinator
- Abductor Pollicis Longus
- Extensor Pollicis Brevis
- Extensor Pollicis Longus
- Extensor Pollicis Proprius
What is the origin of the supinator?
- One head from lateral epicondyle
- One head from posterior surface of the ulna
Where does the supinator insert?
Posterior surface of the radius
What are the actions of the supinator?
- Supination of the forearm
What is the blood supply of the supinator?
Radial recurrent artery
What is the origin of abductor pollicis longus?
- Interosseous membrane
- Adjacent posterior surfaces of the radius and ulna
Where does abductor pollicis longus insert?
Lateral side of the base of metacarpal 1
What are the actions of abductor pollicis longus?
Abduction of the thumb
What is the blood supply of abductor pollicis longus?
Posterior interosseous artery
What is the origin of extensor pollicis brevis?
- Posterior surface of the radius
- Interosseous membrane
Where does extensor pollicis brevis insert?
Base of the proximal phalanx of the thumb
What are the actions of extensor pollicis brevis?
- Extension of MCP joint of the thumb
- Extension of the carpometacarpal joint of the thumb
What is the blood supply of extensor pollicis brevis?
Posterior interosseous artery
What is the origin of extensor indicis proprius?
- Posterior surface of the ulna
- Interosseous membrane
(distal to extensor pollicis longus)
Where does extensor indicis proprius insert?
Extensor hood of the index finger
