Muscles of the Posterior Compartment of the Forearm

Question 1

List the Superficial Layer of Muscles in the Posterior Compartment of the Forearm

Answer 1

Brachioradialis
Extensor Carpi Radialis Longus
Extensor Carpi Radialis Brevis
Extensor Digitorum
Extensor Digiti Minimi
Extensor Carpi Ulnaris

Question 2

List the Deep Layer of Muscle in the Posterior Compartment of the Forearm

Answer 2

Supinator

Question 3

List the Deep Layer (outcropping) of Muscles in the Posterior Compartment of the Forearm

Answer 3

Abductor Pollicis Longus
Extensor Pollicis Longus
Extensor Pollicis Brevis
Extensor Indicis

Question 4

Abductor Pollicis Longus - Origin

Answer 4

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

Question 5

Abductor Pollicis Longus - Insertion

Answer 5

Base of 1st metacarpal

Question 6

Abductor Pollicis Longus - Innervation

Answer 6

Posterior interosseous nerve (C7, C8)

Continuation of deep branch of radial nerve

Question 7

Abductor Pollicis Longus - Action(s)

Answer 7

Extends wrist joint, carpometacarpal joints

Abducts thumb and extends it at carpometacarpal joint

Question 8

Extensor Pollicis Longus - Origin

Answer 8

Posterior surface of middle third of ulna and interosseous membrane

Question 9

Extensor Pollicis Longus - Insertion

Answer 9

Dorsal aspect of base of distal phalanx of thumb

Question 10

Extensor Pollicis Longus - Innervation

Answer 10

Posterior interosseous nerve (C7, C8)

Continuation of deep branch of radial nerve

Question 11

Extensor Pollicis Longus - Action(s)

Answer 11

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

Question 12

Extensor Pollicis Brevis - Origin

Answer 12

Posterior surface of distal third of radius and interosseous membrane

Question 13

Extensor Pollicis Brevis - Insertion

Answer 13

Dorsal aspect of base of proximal phalanx of thumb

Question 14

Extensor Pollicis Brevis - Innervation

Answer 14

Posterior interosseous nerve (C7, C8)

Continuation of deep branch of radial nerve

Question 15

Extensor Pollicis Brevis - Action(s)

Answer 15

Extends wrist joint, carpometacarpal joints
Extends proximal phalanx of thumb at metacarpophalangeal joint
Extends carpometacarpal joint

Question 16

Extensor indicis - Origin

Answer 16

Posterior surface of distal third of ulna and interosseous membrane

Question 17

Extensor indicis - Insertion

Answer 17

Extensor expansion of 2nd finger

Question 18

Extensor indicis - Innervation

Answer 18

Posterior interosseous nerve (C7, C8)

Continuation of deep branch of radial nerve

Question 19

Extensor indicis - Action(s)

Answer 19

Extends wrist joint, carpometacarpal joints
Extends 2nd finger (enabling its independent extension)
Helps extend hand at wrist