Posterior Lower Arm Muscles

Question 1

Extensor carpi radialis brevis

Answer 1

O: lateral epicondyle of humerus
I: base of metacarpal III
A: extension and abduction at wrist
Inn: radial n

Question 2

Extensor digitorum

Answer 2

O: lateral epicondyle
I: posterior surfaces of phalanges 2-5
A: extend digits 2-5 and wrist
Inn: deep radial n

Question 3

Extensor carpi ulnaris

Answer 3

O: lateral epicondyle and posterior ulna
I: base of metacarpal V
A: extend and adduct wrist
Inn: deep radial n

Question 4

Supinator

Answer 4

O: lateral epicondyle and ulna
I: anterolateral radius
A: Supinates forearm and hand
Inn: deep radial n

Question 5

Extensor indicis

Answer 5

O: posterior ulna and interosseous membrane
I: posterior proximal phalanx of digit 2
A: extends digit two
Inn: deep radial n

Question 6

Abductor pollicis longus

Answer 6

O: posterior, proximal ulna, radius, interosseous membrane
I: metacarpal I and trapezium
A: abduct thumb and wrist
Inn: deep radial n

Question 7

Extensor pollicis longus

Answer 7

O: posterior, lateral ulna and interosseous membrane
I: base of distal phalanx of thumb
A: extend thumb and abduct wrist
Inn. Deep radial n

Question 8

Extensor pollicis brevis

Answer 8

O: posterior distal radius and interosseous membrane
I: base of proximal phalanx of thumb
A: extend thumb and abduct wrist
Inn: deep radial n

Question 9

Extensor carpi radialis longus

Answer 9

O: lateral supracondular ridge of humerus
I: base of metacarpal II
A: extension and abduction at wrist
Inn: radial n