Posterior Forearm Muscles

Question 1

Brachioradialis

Answer 1

O: Proximal 2/3 of lateral supracondylar ridge of humerus

I: Styloid process of radius

A: Flexes elbow and maintains half pronated position

N: Radial

Question 2

Extensor carpi radialis longus

Answer 2

O: Distal 1/3 of the lateral supracondylar ridge of humerus

I: Base of second metacarpal

A: Extends the wrist, Radially deviates the wrist

N: Radial

Question 3

Externsor carpi radialis brevis

Answer 3

O: (CET) Common extensor tendon on lateral epicondyle of humerus

I: Base of third metacarpal

A: Extends the wrist, Radially deviates the wrist

I: Radial

Question 4

Extensor digitorum

Answer 4

O: (CET) Common extensor tendon on lateral epicondyle of humerus

I: Bases of middle and distal phalanges of 2nd through 5th fingers

A: Extends fingers

N: Radial

Question 5

Extensor digiti minimi

Answer 5

O: (CET) Common extensor tendon on lateral epicondyle of humerus

I: Distal digital expansion of 5th

A: MCP, PIP, and DIP joints of 5th digit; ulnar abduction of the hand

N: Radial

Question 6

Extensor carpi ulnaris

Answer 6

O: (CET) Common extensor tendon on lateral epicondyle of humerus

I: Base of 5th metacarpal

A: Extends wrist and ulnar deviates

N: Radial

Question 7

Supinator

Answer 7

O: Lateral epicondyle of humerus, radial collateral ligament, annular ligament and supinator crest of ulna

I: Anterior, lateral surface of proximal 1/3 of radial shaft

A: Supinate the forearm

N: Radial

Question 8

Abductor pollicis longus

Answer 8

O: Posterior surface of middle third of ulna, radius and interosseous membrane

I: Base of 1st metacarpal

A: Radial deviation, abduction of thumb

N: Radial

Question 9

Extensor pollicis longus

Answer 9

O: Proximal surface of middle third of ulna and interosseous membrane

I: Base of distal phalanx of thumb

A: Radial deviation, adduction of thumb, extension of MCP and IP of thumb

N: Radial

Question 10

Extensor pollicis brevis

Answer 10

O: Posterior surface of radius and interossereous membrane

I: Base of proximal phalanx of thumb

A: Radial deviation of the hand, extension of MCP and carpometacarpal joints of thumb

N: Radial

Question 11

Extensor indicis

Answer 11

O: Proximal surface of ulna and interosseous membrane

I: Posterior digital expansion of 2nd digit (index finger)

A: Extension of wrist joint, Extension of MCP, PIP, and DIP joints of the index finger

N: Radial