Muscles of the Forearm - Extensor Group / Deep Layer

Question 1

Supinator

Answer 1

O: posterolateral surface of ulna below radial noch + lateral epicondyle + radial collateral and annular ligaments

I: proximal shaft of radius

A: supination of forearm and hand

In: radial nerve

Question 2

Abductor Pollicis Longus

Answer 2

O: posterior surface of the ulna and radius + interosseous membrane

I: base of first metacarpal

A: abduction and extension of thumb

In: radial nerve

Question 3

Extensor Pollicis Brevis

Answer 3

O: posterior surface of radius + interosseous membrane

I: proximal phalanx of the thumb

A: extension of proximal phalanx of thumb

In: radial nerve

Question 4

Extensor Pollicis Longus

Answer 4

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

I: distal phalanx of thumb

A: extension of distal phalanx of thumb

In: radial nerve

Question 5

Extensor Indicis

Answer 5

O: posterior surface of ulna + interosseous membrane

I: extensor expansion of index finger

A: extension of index finger

In: radial nerve