Wrist extensors

Question 1

Extensor carpi radialis Longus

Answer 1

O: lower third of lateral supracondylar ridge of humerus, intermuscular septa

I: posterior surface of base of second metacarpal

D:

A: extends and adducts wrist

N: radial nerve (C6,7)

Question 2

Extensor carpi radialis brevis

Answer 2

O: lateral epicondyle via common extensor tendon

I: posterior surface of base of third metacarpal

D:

A: extends and abducts wrist

N: posterior interosseous branch of radial nerve (C7,8)

Question 3

Extensor carpi ulnaris

Answer 3

O: lateral epicondyle via common extensor tendon

I: medial side of fifth metacarpal base

D:

A: extends and adducts wrist

N: posterior interosseous nerve (C7,8)

Question 4

Extensor digitorum

Answer 4

O: lateral epicondyle via common extensor tendon, intermuscular septa

I: lateral and dorsal surfaces of second to fifth digits

D:

A: extends fingers and wrist

N: posterior interosseous branch of radial nerve (C7,8)

Question 5

Extensor indicis

Answer 5

O: lower part of posterior surface of ulna, interosseous membrane

I: dorsal digital expansion on back of proximal phalanx if index finger

D:

A: extends index finger and wrist

N: posterior interosseous nerve (C7,8)

Question 6

Extensor digiti minimi

Answer 6

O: lateral epicondyle via common extensor tendon, intermuscular septa

I: dorsal digital expansion of fifth digit

D:

A: extends fifth digit and wrist

N: posterior interosseous nerve (C7,8)

Question 7

Extensor pollicis longus

Answer 7

O: middle third of posterior surface of ulna, interosseous membrane

I: dorsal surface of distal phalanx of thumb

D:

A: extends thumb and wrist, abducts wrist

N: posterior interosseous nerve (C7,8)

Question 8

Extensor pollicis brevis

Answer 8

O: posterior surface of radius, interosseous membrane

I: dorsolateral base of proximal phalanx of thumb

D:

A: extends thumb and wrist, abducts wrist

N: posterior interosseous nerve (C7,8)