Muscles of Posterior compartment of forearm

Question 1

Brachioradialis Origin

Answer 1

Lateral supra-epicondylar ridge of humerus

Question 2

Brachioradialis Insertion

Answer 2

Lateral surface of distal end of radius, proximal to styloid process

Question 3

Brachioradialis Action

Answer 3

• Weak flexion of forearm

* Maximal when forearm is in midpronated position

Question 4

Extensor carpi radialis longus Origin

Answer 4

Lateral supra-epicondylar ridge of humerus

Question 5

Extensor carpi radialis longus Insertion

Answer 5

Dorsal aspect of base of 2nd metacarpal

Question 6

Extensor carpi radialis longus Action-2

Answer 6

• Extend wrist

- Abduct hand (Radial Deviation)

Question 7

Extensor carpi radialis brevis Origin

Answer 7

Lateral epicondyle of humerus

Question 8

Extensor carpi radialis brevis Insertion

Answer 8

Dorsal aspect of base of 3rd metacarpal

Question 9

Extensor carpi radialis brevis Action-2

Answer 9

• Extend wrist
• Abduct hand (Radial deviation)

*When fist is clenched

Question 10

Extensor digitorum Origin

Answer 10

Lateral epicondyle of humerus

Question 11

Extensor digitorum Insertion

Answer 11

Extensor expansions of medial 4 fingers

Question 12

Extensor digitorum Action

Answer 12

Extends medial 4 fingers at both the metacarpophalangeal joints and interphalangeal joints

Question 13

Extensor digiti minimi Origin

Answer 13

Lateral epicondyle of humerus

Question 14

Extensor digiti minimi Insertion

Answer 14

Extensor expansion of 5th finger

Question 15

Extensor digiti minimi Action

Answer 15

Extends 5th finger at both the metacarpophalangeal joints and interphalangeal joints

Question 16

Extensor carpi ulnaris Origin-2

Answer 16

• Lateral epicondyle of humerus

- Posterior border of ulna

Question 17

Extensor carpi ulnaris Insertion

Answer 17

Dorsal aspect of base of 5th metacarpal

Question 18

Extensor carpi ulnaris Action-2

Answer 18

• Extends wrist*
• Adducts hand (Ulnar deviation)

*Active when fist clenching

Question 19

Supinator Origin-4

Answer 19

• Lateral epicondyle of humerus
• Radial collateral and anular ligaments
• Supinator fossa
• Crest of ulna

Question 20

Supinator Insertion

Answer 20

Lateral, posterior, and anterior surfaces of proximal 1/3 of radius

Question 21

Supinator Action

Answer 21

Supinates forearm

Question 22

Abductor pollicis longus Origin

Answer 22

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

Question 23

Abductor pollicis longus Insertion

Answer 23

Base of 1st metacarpal

Question 24

Abductor pollicis longus Action

Answer 24

• Abducts thumb

- Extends at carpometacarpal joint

Question 25

Extensor pollicis longus Origin

Answer 25

Posterior surface of middle third of ulna and interosseous membrane

Question 26

Extensor pollicis longus Insertion

Answer 26

Dorsal aspect of base of distal phalanx of thumb

Question 27

Extensor pollicis longus Action-2

Answer 27

• Extends distal phalanx of thumb at interphalangeal joint

- Extends metacarpophalangeal and carpometacarpal joints

Question 28

Extensor pollicis brevis Origin

Answer 28

Posterior surface of distal 1/3 of radius and interosseous membrane

Question 29

Extensor pollicis brevis Insertion

Answer 29

Dorsal aspect of base of proximal phalanx of thumb

Question 30

Extensor pollicis brevis Action

Answer 30

• Extends proximal phalanx of thumb

- Extends carpometacarpal joint

Question 31

Extensor Indicis Origin

Answer 31

Posterior surface of distal 1/3 of ulna and interosseous membrane

Question 32

Extensor Indicis Insertion

Answer 32

Extensor expansion of 2nd finger

Question 33

Extensor Indicis Action

Answer 33

Extends 2nd finger

Also helps extend hand at wrist