The Forearm

Question 1

In general, where do the flexors of the forearm originate from?

Answer 1

medial epicondyle of humerus via common flexor tendon

Question 2

How many layers can the forearm flexors be organized into?

Answer 2

3 layers - superficial, intermediate, and deep

Question 3

What are the general basic functions of the muscles in the flexor compartment of the forearm?

Answer 3

• actively flex digits
• actively flex, abduct and adduct the hand at the wrist
• initiate or assist pronation of the hand (rotate radius)
• act to a lesser degree to flex the forearm

Question 4

What nerve serves to innervate most of the muscles in the flexor compartment of the forearm?

Answer 4

median nerve (exception is flexor carpi ulnaris, ulnar nerve)

Question 5

What serves as the lateral border between the flexor and extensor compartments of the forearm?

Answer 5

brachioradialis muscle

Question 6

What does the flexor retinaculum attach to in order to create a fibro-osseous canal known as the carpal tunnel?

Answer 6

laterally: trapezium and tubercle of scaphoid
medially: hamulus of hamate and pisiform

Question 7

What transverse the carpal tunnel?

Answer 7

tendons of intermediate and deep layer musculature as the median nerve

Question 8

What muscle is responsible for fine movements of the digits?

Answer 8

flexor digitorum profundus

Question 9

The profundus must pass through the apertures w/in the tendons of what muscle?

Answer 9

flexor digitorum superficialis

Question 10

In general, where do the muscles of the extensor compartment of the forearm originate from?

Answer 10

lateral epicondyle of the ulna

Question 11

How many layers are the muscles of the extensor compartment of the forearm arrange into?

Answer 11

2 layers - superficial (5 muscles) and deep (5 muscles)

Question 12

The tendons of what muscles form the ‘anatomical snuff box’?

Answer 12

posterior - extensor pollicis longus
anterior/superiorly - extensor pollicis brevis and abductor pollicis longus
(floor is scaphoid bone)

Question 13

What can be located crossing the floor of the “anatomical snuff box”?

Answer 13

radial artery

Question 14

What are the 4 branches coming off the radial artery in the forearm?

Answer 14

• radial recurrent a.
• muscular branches
• palmar carpal branch
• superficial palmer branch

Question 15

What branch of the radial artery arises just before it passes to the dorsum and participates in the formation of the superficial palmer arterial arch?

Answer 15

superficial palmer branch

Question 16

What branch of the radial artery ascends radial on the surface of the supinator muscle to anastomose with the radial collateral branch of the deep brachial artery?

Answer 16

radial recurrent a.

Question 17

What are the 7 branches coming off the ulnar artery in the forearm?

Answer 17

• anterior ulnar recurrent
• posterior ulnar recurrent a.
• common interosseous a.
• muscular branches
• palmer carpal branch
• dorsal carpal branch
• deep palmar branch

Question 18

What are the 2 branches the common interosseous a. from the ulnar a. form?

Answer 18

• anterior interosseous a.

- posterior interosseous artery (PIA) (branches to interosseous recurrent a.)

Question 19

What nerve supplies innervation to all but one of the muscles of the anterior forearm?

Answer 19

median nerve (C6-T1)

Question 20

What nerve branches off the median n to accompany the anteriro interosseous artery and innervat the msucles of hte deep layer of flexor muscles of the forearm?

Answer 20

anterior interrosseous nerve

Question 21

What is the last branch of the median nerve which arises proximal to the flexor retinaculum?

Answer 21

palmer cutaneous branch

Question 22

What is the median nerve susceptible to?

Answer 22

compression by inflammation of the flexor retinaculum (carpal tunnel syndrome)

Question 23

What nerve course posterior to the medial epicondyl of the humerus and enters the forearm by passing between the two heads of origin of the flexor carpi ulnaris? The nerve enters the wrist by passing superficial to the flexor retinaculum lateral to the pisiform

Answer 23

ulnar nerve ((C8, T1)

Question 24

What are the two nerve branches from the radial nerve in the forearm?

Answer 24

• superficial branch

- deep branch (posterior interosseous n.)