Extrinsic Thumb Musculature

Question 1

4 extrinsic thumb muscles

Answer 1

flexor pollicis longus

extensor pollicis longus

extensor pollicis brevis

abductor pollicis longus

Question 2

flexor pollicis longus

Answer 2

produces MCP and IP flexion

Question 3

extensor pollicis longus

Answer 3

produces extensor force at both the IP and MCP joints

will also extend and ADD the CMC joint of the thumb

Question 4

extensor pollicis brevis

Answer 4

produces extension at the MCP (inserts at the base of the proximal phalanx)

radially deviate the wrist and ABD the first CMC joint

Question 5

Abductor pollicis longus

Answer 5

produces abduction of the CMC joint

radially deviate the wrist

Question 6

what is essential for proper functioning of the thumb extrinsic musculature

Answer 6

wrist position to provide optimal length-tension relationship

Question 7

what happens when the wrist is in full extension

Answer 7

the FPL is very ineffective at IP joint flexion

passively insufficient