Extensors of the forearm

Question 1

1.Which muscles make up the superficial layer of the posterior forearm (extensors)?

Answer 1

Brachioradialis;

extensor carpi radialis longus;

extensor carpi radialis brevis;

extensor digitorum;

extensor digiti minimi;

extensor carpi ulnaris

Question 2

2. What is the main action of the brachioradialis?

Answer 2

Flexion of the forearm and rotation of the forearm to the mid-prone position

Question 3

3. What are the actions of extensor carpi radialis longus?

Answer 3

Extension and abduction of the hand at the wrist joint

Question 4

4. What are the actions of extensor carpi radialis brevis?

Answer 4

Extension and abduction of the hand at the wrist joint

Question 5

5. What is the action of extensor digitorum?

Answer 5

Extension of the fingers and the hand at the wrist joint.

Question 6

6. What is the action of extensor digiti minimi?

Answer 6

Extension of the metacarpophalangeal (MP) joint of the little finger.

Question 7

7. What are the actions of extensor carpi ulnaris?

Answer 7

Extension and adduction of the hand at the wrist joint.

Question 8

8. What is the nerve supply of all the superficial extensors of the forearm except Brachioradialis and extensor carpi longus?

Answer 8

Deep branch/posterior interosseous branch of radial nerve.

Question 9

16. Which muscles make up the deep layer of the posterior forearm (extensors)?

Answer 9

Supinator;

abductor pollicis longus;

extensor pollicis brevis;

extensor pollicis longus;

extensor indicis.

Question 10

17. What is the main action of the supinator muscle?

Answer 10

Supination of the forearm.

Question 11

18. What are the actions of abductor pollicis longus?

Answer 11

Abduction and extension of the thumb.

Question 12

19. What is the action of extensor pollicis brevis?

Answer 12

Extension of the metacarpophalangeal joint of the thumb.

Question 13

20. What is the action of extensor pollicis longus?

Answer 13

Extension of the distal phalanx of the thumb.

Question 14

21. What is the action of extensor indicis?

Answer 14

Extension of the metacarpophalangeal joint of the index finger.

Question 15

22. What nerve supplies the deep extensors of the posterior forearm?

Answer 15

The deep branch of the radial nerve.

Question 16

23. Which nerve supplies all the muscles in the posterior (extensor) compartment of the forearm?

Answer 16

Radial nerve (C5-T1).

Question 17

24. Which nerve supplies flexor carpi ulnaris and the medial half of flexor digitorum profundus in the forearm?

Answer 17

Ulnar nerve (C8-T1).

Question 18

25. Which nerve supplies all the muscles in the anterior compartment of the forearm except for 1.5 muscles?

Answer 18

Median nerve (C5-T1).

Question 19

26. Which muscles in the anterior forearm are NOT supplied by the median nerve?

Answer 19

Flexor carpi ulnaris and the medial half of flexor digitorum profundus (these are supplied by the ulnar nerve).

Question 20

27. What does the posterior cutaneous nerve of the forearm; a branch of the radial nerve; supply?

Answer 20

It supplies the skin on the posterior aspect of the forearm.

Question 21

28. What does the superficial branch of the radial nerve supply?

Answer 21

It supplies the skin on the dorsum of the hand; including the lateral three and a half fingers (thumb; index; middle; and lateral half of the ring finger); excluding the nail beds.

Question 22

29. Which nerve supplies touch sensation to the posterior surface of the forearm?

Answer 22

Radial nerve (C5-T1).

Question 23

30. Which nerve supplies touch sensation to the medial surface of the forearm?

Answer 23

Medial cutaneous nerve of the forearm (also called medial antebrachial cutaneous nerve; C8-T1).

Question 24

31. Which nerve supplies touch sensation to the lateral surface of the forearm?

Answer 24

Musculocutaneous nerve (via the lateral cutaneous nerve of the forearm; C5-C7).

Question 25

32. Which nerve can be damaged by entrapment or hypercontraction of the flexor carpi ulnaris muscle?

Answer 25

Ulnar nerve.

Question 26

33. Which nerve can be compressed by entrapment or hypercontraction of the pronator teres muscle?

Answer 26

Median nerve.

Question 27

34. Which nerve can be affected by entrapment or hypercontraction of the supinator muscle?

Answer 27

Deep branch of the radial nerve.