Forearm Muscles: Posterior

Question 0

Extensor Carpi Radialis Longus

Answer 0

O: lateral supra epicondylar ridge of humerus
Ins: dorsal base of 2nd metacarpal
Inn: radial nerve C5-C7
A: extend and abduct wrist joint
      - active during fist clenching

Question 1

Brachioradialis

Answer 1

O: later supra epicondylar ridge of humerus
Ins: lateral surface of radius proximal to styloid process
Innv: Radial nerve C5-C7
A: flexion of elbow joint

Question 2

Extensor Carpi Radialis Brevis

Answer 2

O: lateral epicondyle of humerus
Ins: dorsal base 3rd metacarpal
Inv: deep radial nerve C7-C8
A: extend and abduct wrist

Question 3

Extensor Digitorum

Answer 3

O: lateral epicondyle of humerus
Ins: extensor expansions of medial 4 fingers
Inv: deep branch radial nerve C7-C8
A: extend wrist joint and medial 4 fingers at MP and IP joints

Question 4

Extensor Digiti Minimi

Answer 4

O: lateral epicondyle of humerus
Ins: extensor expansion 5th finger
Inv: posterior Interosseous nerve C7-C8
A: extends wrist joint; extends 5th finger at MP & IP joint

Question 5

Extensor Carpi Ulnaris

Answer 5

O: lateral epicondyle of humerus & posterior border of ulna
Ins: dorsal base 5th metacarpal
Inv: posterior Interosseous nerve C7, C8
A: extends and adducts wrist joint

Question 6

Supinator

Answer 6

O: Lateral epicondyle of humerus
Radial collateral and annular lips
Supination fossa
Crest of ulna
Ins: lateral posterior and anterior surface of radius
Inv: deep branch radial nerve C7-C8
A: supinates forearm, rotates radius to turn palm anteriorly

Question 7

Abductor Pollicis Longus

Answer 7

O:posterior ulna radius and interosseous memb
Ins: base 1st metacarpal
Inv: posterior Interosseous nerve C7, C8
A: extends wrist joint
abducts thumb and extends it at CM joint

Question 8

Extensor pollicis Longus

Answer 8

O: posterior surface ulna and Interosseous memb
Ins: dorsal base distal phalanx of thumb
Inv: posterior Interosseous nerve
A: extend wrist joint
Extend distal phalanx of thumb at IP joint

Question 9

Extensor Pollicis Brevis

Answer 9

O: posterior surface of radius and Interosseous memb
Ins: dorsal base of proximal phalanx of thumb
Inv: posterior Interosseous nerve C7-C8
A: extend wrist joint and proximal phalanx of thumb at MP joint

Question 10

Extensor Indicis

Answer 10

O: posterior surface ulna and Interosseous membrane
Ins: extensor expansion of 2nd finger
Inv: posterior Interosseous nerve
A: extends wrist joint
Extends 2nd finger (independent expansion)