Deep Muscles Of Posterior Forearm

Question 1

What are the muscles in the deep compartment of posterior forearm? (5)

Answer 1

Supinator, adductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, extensor incidis

Question 2

What are they all innervated by?

Answer 2

Radial nerve

Question 3

Origin of supinator

Answer 3

One head from lateral epicondyle of humerus
Other head from posterior surface of ulna

Question 4

Insertion of supinator

Answer 4

Posterior surface of radius

Question 5

Action of supinator

Answer 5

Supinates forearm

Question 6

Origin of adductor pollicis longus

Answer 6

Interosseous membrane + adjacent posterior surface of radius + ulna

Question 7

Insertion of adductor pollicis longus

Answer 7

Lateral side of base of metacarpal I

Question 8

Action of adductor pollicis longus

Answer 8

Adducts thumb

Question 9

Origin of extensor pollicis brevis

Answer 9

Posterior surface of radius + interosseous membrane

Question 10

Insertion of extensor pollicis brevis

Answer 10

Base of proximal phalanx of thumb

Question 11

Action of extensor pollicis brevis

Answer 11

Extends at MCPJ and CMCJ of thumb

Question 12

Origin of extensir pollicis longus

Answer 12

Posterior surface of ulna + interosseous membrane

Question 13

Insertion of extensor pollicis longus

Answer 13

Distal phalanx of thumb

Question 14

Action of extensor pollicis longus

Answer 14

Extends all joints of thumb

Question 15

Origin of extensor incidis

Answer 15

Posterior surface of ulna + interosseous membrane

Question 16

Insertion of extensor incidis

Answer 16

Extensor hood of index finger

Question 17

Action of extensor incidis

Answer 17

Extends index finger