posterior deep forearm muscles

Question 1

innervation of posterior compartment

Answer 1

radial N

Question 2

supinator origin and insertion

Answer 2

o - lateral epicondyle
i - lateral proximal 1/3 radius

Question 3

supinator action

Answer 3

supinate forearm

Question 4

abductor pollicis longus origin and insertion

Answer 4

o - mid-ulna, radius, and interosseous membrane
i - base of 1st metacarpal

Question 5

abductor pollicis longus action

Answer 5

abduct thumb at CMC

Question 6

extensor pollicis longus origin and insertion

Answer 6

o - posterior mid-ulna and interosseous membrane
Goes medial to dorsal radial tubercle and
i - base of distal phalanx of thumb

Question 7

extensor pollicis longus action

Answer 7

extend thumb at CMC, MCP, IP

Question 8

extensor pollicis brevis origin and insertion

Answer 8

o - posterior distal radius and interosseous membrane
i - base of proximal phalanx of thumb

Question 9

extensor pollicis brevis action

Answer 9

extend thumb at CMC, MCP

Question 10

extensor indicis origin and insertion

Answer 10

o - posterior ulna
i - distal phalanx of 2nd digit via tendon fo extensor digitorum (distal expansion)

Question 11

extensor indicis action

Answer 11

extend 2nd digit at MCP, PIP, DIP
extend radiocarpal joint

Question 12

posterior forearm muscles in order from most proximal to distal

Answer 12

-supinator
-abductor pollicis longus
-extensor pollicis longus
-extensor pollicis brevis
-extensor indicis

Question 13

what landmark does the tendon of extensor pollicis longus go around and why

Answer 13

Dorsal radial tubercle
-ensures extension instead of abduction because of angle