Kinesiology: Long and Short Muscles of the Thumb

Abduct thumb; assists in opposition

*Actions of abductor pollicis brevis?

Flex thumb; assists in opposition

*Actions of flexor pollicis brevis?

8

*How many muscles act upon the thumb?

deep; inaccessible

*The belly of the flexor pollicis longus lies on the forearm's anterior surface, (superficial/deep) to the wrist flexors, and is ___.

Flexor pollicis brevis

*What thumb muscle has a superficial and deep head origin?

Adductor pollicis

*Which is the longest of the thumb's short muscles?

Flexor pollicis longus

*Which muscle is deep and inaccessible?

Opponens pollicis

*Which muscle is responsible for the opposition of the thumb?

Extensor pollicis longus tendon; Extensor pollicis brevis and abductor pollicis longus tendon

*Which tendons form the anatomical snuffbox?

Adductor pollicis brevis; flexor pollicis brevis

*Which thumb muscles assist in thumb opposition?

Adducts thumb

Action of adductor pollicis?

Base of proximal phalanx of thumb

Insertion of abductor pollicis brevis?

Base of 1st metacarpal

Insertion of abductor pollicis longus?

Trapezium, trapezoid, capitate

What is the origin of the flexor pollicis brevis' DEEP head?

Flexor retinaculum

What is the origin of the flexor pollicis brevis' SUPERFICIAL head?

Opposition of thumb

Action of opponens pollicis?

Abduct/extend the thumb

Actions of abductor pollicis longus?

Extend the thumb

Actions of extensor pollicis longus and brevis?

Base of proximal phalanx of the thumb

Insertion of adductor pollicis?

Base of proximal phalanx of thumb

Insertion of extensor pollicis brevis?

Base of distal phalanx of thumb

Insertion of extensor pollicis longus?

Entire 1st metacarpal

Insertion of opponens pollicis?

Opponens pollicis (inserts in the 1st metacarpal)

Of the 4 short muscles of the thumb: which one's insertion is NOT the proximal phalanx of the thumb?