muscles of the forearm: posterior

Question 1

Brachioradialis

Answer 1

O: lateral supracondylar ridge at distal end of humerus
I: base of styloid process of radius
N: radial nerve
K: forearm flexion

Question 2

Extensor carpi radialis longus

Answer 2

O: lateral supracondylar ridge of humerus
I: base of second metacarpal
N: radial nerve. roots c6,c7
K: extends wrist and abducts wrist

Question 3

Extensor carpi radialis brevis

Answer 3

O: lateral epicondyle of humerus
I: base of third metacarpal
N: deep branch of radial nerve
K: extends and abducts wrist

Question 4

Extensor digitorum

Answer 4

O: lateral epicondyle of humerus
I: four tendons into extensor expansions and distal phalanges of fingers 2-5
N: posterior interosseous nerve, roots c5, c6
K: prime mover of finger extension

Question 5

Extensor carpi ulnaris

Answer 5

O: lateral epicondyle of humerus and posterior border of ulna
I: base of fifth metacarpal
N: posterior interosseous nerve
K: extends wrist, adducts wrist

Question 6

Supinator

Answer 6

O: lateral epicondyle of humerus; proximal ulna
I: proximal end of radius
N: posterior interosseous nerve
K: assists bicep brachii to forcibly supinate forearm, works alone in slow supination

Question 7

Abductor pollicis longus

Answer 7

O: posterior surface of radius and ulna, interosseous membrane
I: base of first metacarpal and trapezium
N: posterior interosseous nerve
K: abducts and extends thumb

Question 8

Extensor pollicis brevis and longus

Answer 8

O: dorsal shaft of radius and ulna, interosseous membrane
I: base of proximal and distal phalanx of thumb
N: posterior interosseous nerve
K: extends thumb