Posterior Deep Muscles Of Forearm

Question 1

What is the action of wrist extension?

Answer 1

Helps in extending the finger joints

Specifically extends the index finger and the thumb.

Question 2

Which joint does wrist extension primarily affect?

Answer 2

Carpometacarpal joint

It also extends the metacarpophalangeal and interphalangeal joints.

Question 3

What is the nerve supply for wrist extension?

Answer 3

Posterior interosseous nerve

This nerve is a branch of the radial nerve.

Question 4

Fill in the blank: The tendon for the index finger lies _______ to the distal phalanx of the thumb.

Answer 4

medial

Question 5

What are the insertions for the abductor pollicis longus?

Answer 5

Dorsal surface of the base of the first metacarpal

It also assists in abducting the thumb.

Question 6

List the origins of the extensor pollicis longus.

Answer 6

• Posterior surface of the ulna
• Adjoining interosseous membrane
• Middle one-third of the posterior surface of the radius

These origins contribute to the muscle’s action in thumb extension.

Question 7

True or False: The supinator muscle originates from the lateral epicondyle.

Answer 7

True

Question 8

What is the role of the supinator muscle?

Answer 8

Supination of the forearm

It assists in turning the palm upward.

Question 9

Fill in the blank: The extensor indicis is responsible for extending the _______.

Answer 9

index finger

Question 10

What is the action of the extensor pollicis brevis?

Answer 10

Extends the thumb

It also assists in abducting the thumb.

Question 11

List the components of the origin for the abductor pollicis longus.

Answer 11

• Posterior surface of the radius
• Posterior surface of the ulna
• Interosseous membrane

These components help in the muscle’s action of abducting the thumb.

Question 12

What anatomical structure does the supinator muscle pierce?

Answer 12

Interosseous membrane

This allows the muscle to access the radial nerve.