Posterior Antebrachium (Deep)

Question 1

Supinator

Answer 1

O: lateral epicondyle of humerus, elbow ligaments, ulnar crest

I: proximal posterolateral radius

Inn: radial N (posterior interosseus) (c5-6)

BS: radial A and deep A of arm (profunda brachii)

A: supinate forearm

Question 2

Abductor Pollicis Longus

Answer 2

O: posterior ulna, radius and interosseus membrane

I: 1st metacarpal (lateral)

Inn: Radial N (posterior interosseous) (c7-8)

BS: posterior interosseous A

A: abduct, extend thumb at CMC joint

Question 3

Extensor Pollicis Brevis

Answer 3

O: posterior radius and interosseous membrane

I: proximal phalanx of thumb (dorsal)

Inn: Radial N (posterior interosseous) (c7-8)

BS: posterior interosseous A

A: extend proximal thumb phalanx ant MCP joint

Question 4

Extensor Pollicis Longus

Answer 4

O: Posterior mid-ulna and interosseous membrane

I: distal phalanx of thum (dorsal)

Inn: Radial N (posterior interosseous) (c7-8)

BS: posterior interosseous A

A: extend thumb phalanx at CMC & IP joints

Question 5

Extensor Indicis

Answer 5

O: posterior ulna and interosseous membrane

I: 2nd digit extensor expansion

Inn: radial N (posterior interosseous) (c7-8)

BS: posterior interosseous A

A: extend 2nd digit, extend hand