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Question 1

Which muscles facilitate thumb adduction?

Answer 1

1. adductor pollicis
2. 1st dorsal interosseous muscle

Question 2

Describe the action of thumb opposition and the muscles involved.

Answer 2

Thumb opposition, a movement at the carpometacarpal joint, involves the opponens pollicis, which causes the thumb to “cup” the palm. Full opposition also includes the reinforcing actions of the adductor pollicis and flexor pollicis longus (FPL) for pressure against fingertips.

Question 3

At which joints do the main movements of the thumb occur?

Answer 3

The main thumb movements—extension, flexion, abduction, and adduction—occur at the carpometacarpal and metacarpophalangeal joints.

Question 4

What is the function of the Abductor Pollicis Brevis (APB)?

Answer 4

Abducts the thumb and assists in thumb opposition.

Question 5

How do you test the Abductor Pollicis Brevis?

Answer 5

Abduct the thumb against resistance.