Muscles of Posterior Forearm Deep Layer

Question 0

Insertion of Supinator

Answer 0

Lateral, posterior, and anterior surfaces of proximal third of radius

Question 1

Origin of Supinator

Answer 1

Lateral Epicondyle of of humerus, radial collateral and anular ligaments, supinator fossa, and crest of ulna

Question 2

Innervation of Supinator

Answer 2

Deep brach of radial nerve (C7, C8)

Question 3

Action of Supinator

Answer 3

Supinates forearm rotates radius to turn palm anteriorly or superiorly(if elbow is flexed)

Question 4

Origin of Abductor pollicis longus

Answer 4

Posterior surface of proximal halves of ulna, radius, and interosseous membrane

Question 5

Insertion of Abductor pollicis longus

Answer 5

Base of 1st metacarpel

Question 6

Innervation of Abdutor pollicis longus, extensor pollicis longus, extensor pollicis brevis, and extensor indicis

Answer 6

Posterior interosseous nerve (C7, C8) continuation of deep branch of radial nerve

Question 7

Action of abductor pollicis longus

Answer 7

Extends the wrist joint

Abducts thumb and extends it at carpometacarpal joint

Question 8

Origin of Extensor pollicis longus

Answer 8

Posterior surface of middle third of ulna and interosseous membrane

Question 9

Insertion of Extensor pollicis longus

Answer 9

Dorsal aspect of base of distal phalanx of thumb

Question 10

Action of Extensor pollicis longus

Answer 10

Extends wrist joint

Extends distal phalanx of thumb at interphalangeal joint, extends metacarpophalangeal and carpometacarpal joints

Question 11

Origin of Extensor Pollicis Brevis

Answer 11

Posterior surface of distal third of radius and interosseous membrane

Question 12

Insertion of Extensor Pollicis Brevis

Answer 12

Dorsal aspect of base of proximal phalanx of thumb

Question 13

Action of Extensor pollicis brevis

Answer 13

Extends the wrist joint
Extends proximal phalanx of thumb at metacarophalangeal joint
Extends carpometacaral joint

Question 14

Origin of Extensor Indicis

Answer 14

Posterior surface of distal third of ulna and interosseous membrane

Question 15

Insertion of Extensor Indicis

Answer 15

Extensor expansion of 2nd finger

Question 16

Action of Extensor Indicis

Answer 16

Extends wrist joint
Extends 2nd finger(enabling its independent extension)
helps extend hand at wrist.