Muscles of Posterior Compartment

Question 0

Brachioradialis

Insertion

Answer 0

Lateral surface of distal end of radius of promixal to styloid process

Question 1

Brachioradialis

Origin

Answer 1

Proximal two thirds of lateral supraepicondylar ridge of humerus

Question 2

Brachioradialis

Innervation

Answer 2

Radial Nerve (C5, C6, C7)

Question 3

Brachioradialis

Actions

Answer 3

Relatively weak flexion of elbow joint, maximal when forearm is in midpronated position

Question 4

Extensor Carpi Radialis Longus

Origin

Answer 4

Lateral supra-epicondylar ride of humerus

Question 5

Extensor carpi radialis longus

Insertion

Answer 5

Dorsal aspect of base of 2nd metacarpal

Question 6

Extensor Carpi Radialis Longus

Innervation

Answer 6

Radial nerve (C6, C7)

Question 7

Extensor Carpi Radialis Longus

Actions

Answer 7

Extend and abduct wrist joint

Extensor carpi radialis brevis active during fist clenching

Question 8

Extensor carpi radialis brevis

Answer 8

Lateral epicondyle of humerus (common extensor origin)

Question 9

Extensor carpi radialis brevis

Insertion

Answer 9

Dorsal aspect of base of 3rd metacarpal

Question 10

Extensor carpi radialis brevis

Innervation

Answer 10

Deep branch of radial nerve (C7, C8)

Question 11

Extensor carpi radialis brevis

Actions

Answer 11

Extend and abduct wrist joint

Extensor carpi radialis brevis active during fist clenching

Question 12

Extensor Digitorum

Origin

Answer 12

Lateral epicondyle of humerus (common extensor origin)

Question 13

Extensor Digitorum

Insertion

Answer 13

Extensor expansions of medial four fingers

Question 14

Extensor Digitorum

Innervation

Answer 14

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

Question 15

Extensor Digitorum

Actions

Answer 15

Extend wrist joint
Extend medial four fingers primarily at metacarpophalangeal joints
Secondarily at interphalangeal joints

Question 16

Extensor Digiti Minimi

Origin

Answer 16

Lateral epicondyle of humerus (common extensor origin)

Question 17

Extensor Digiti Minimi

Insertion

Answer 17

Extensor expansion of 5th finger

Question 18

Extensor Digiti Minimi

Innervation

Answer 18

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

Question 19

Extensor Digiti Minimi

Actions

Answer 19

Extends wrist joint

Extends 5th finger primarily at metacarpophalangeal joint, secondarily at interphalangeal joint

Question 20

Extensor Carpi Ulnaris

Origin

Answer 20

Lateral epicondyle of humerus

Posterior border of ulna via a shared aponeurosis

Question 21

Extensor Carpi Ulnaris

Insertion

Answer 21

Dorsal aspect of base of 5th metacarpal

Question 22

Extensor Carpi Ulnaris

Innervation

Answer 22

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

Question 23

Extensor Carpi Ulnaris

Actions

Answer 23

Extends and adducts wrist joint (also active during fist flenching)

Question 24

Supinator | Origin

Answer 24

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

Question 25

Supinator | Insertion

Answer 25

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

Question 26

Supinator | Innervation

Answer 26

Deep branch of radial nerve (C7,C8)

Question 27

Supinator | Actions

Answer 27

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

Question 28

Abductor pollicis longus | Origin

Answer 28

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

Question 29

Abductor pollicis longus | Insertion

Answer 29

Base of 1st metacarpal

Question 30

Abductor pollicis longus | Innervation

Answer 30

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

Question 31

Abductor pollicis longus | Actions

Answer 31

Extends wrist joint | Abducts thumb and extends it at carpometacarpal joint

Question 32

Extensor pollicis longus | Origin

Answer 32

Posterior surface of middle third of ulna and interosseous membrane

Question 33

Extensor pollicis longus | Insertion

Answer 33

Dorsal aspect of base of distal phalanx of thumb

Question 34

Extensor pollicis longus | Innervation

Answer 34

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

Question 35

Extensor pollicis longus | Actions

Answer 35

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

Question 36

Extensor pollicis brevis | Origin

Answer 36

Posterior surface of distal third of radius and interosseous membrane

Question 37

Extensor pollicis brevis | Insertion

Answer 37

Dorsal aspect of base of proximal phalanx of thumb

Question 38

Extensor pollicis brevis | Innervation

Answer 38

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

Question 39

Extensor pollicis brevis | Actions

Answer 39

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

Question 40

Extensor Indicis | Origin

Answer 40

Posterior surface of distal third of ulna and interosseous membrane

Question 41

Extensor indicis | Insertion

Answer 41

Extensor expansion of 2nd finger

Question 42

Extensor Indicis | Innervation

Answer 42

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

Question 43

Extensor Indicis | Actions

Answer 43

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