Unit 2 - Upper Limb: Posterior Compartment of Forearm, Deep Muscles (Ex. II)

Question 1

abductor pollicis longus

Answer 1

O: radius and ulna (dorsal surfaces; interosseous membrane)
I: base of 1st metacarpal
Inn: radial N (C7, C8) (P interosseous branch)
A: radiocarpal joint - abduction of hand; carpometacarpal joint of thumb - abduction

Question 2

extensor pollicis brevis

Answer 2

O: radius (P surface); interosseous membrane
I: base of proximal phalanx of thumb
Inn: radial N (C7, C8) (P interosseous branch)
A: radiocarpal joint - abduction (R deviation) of hand; carpometacarpal and MCP joint of thumb - extension

Question 3

supinator

Answer 3

O: olecranon of ulna; L epicondyle of humerus; radial (L) collateral ligament; annular ligament of radius
I: radius (between radial tuberosity and insertion of pronator teres)
Inn: radial N (C6, C7)
A: supination of RU joints

Question 4

extensor pollicis longus

Answer 4

O: P surface of ulna; interosseous membrane
I: base of distal phalanx of thumb
Inn: radial N (C7, C8) (P interosseous branch)
A: wrist - extension and abduction (R deviation) of hand; carpometacarpal of thumb - adduction; MCP and IP joints of thumb - extension

Question 5

extensor indicis

Answer 5

O: P surface of ulna; interosseous membrane
I: P digital extension of digit 2
Inn: radial N (C7, C8) (P interosseous branch)
A: wrist - extension; MCP, PIP, and DIP joints of digit 2 - extension