Forearm

Question 1

Brachioradialis innervation and action?

Answer 1

• Radial n.

- Weak flexion of forearm when forearm is mid-pronated

Question 2

Flexor carpi radialis m. innervation and action?

Answer 2

• Median n.

- Flexes and abducts hand at wrist

Question 3

Palmaris longus m. innervation and action?

Answer 3

• Median n.

- Flexes hand at wrist, tenses palmar aponeurosis

Question 4

Flexor digitorum superficialis m. innervation and action?

Answer 4

• Median n.

- Flexes middle and proximal phalanges (not pollux), flexes hand at wrist

Question 5

Flexor carpi ulnaris m. innervation and action?

Answer 5

• Ulnar n.

- Flexes and adducts hand at wrist

Question 6

Flexor pollicis longus m. innervation and action?

Answer 6

• Median n.

- Flexes phalanges of thumb

Question 7

Flexor digitorum profundus m. innervation and action?

Answer 7

• Lateral 1/2 is medial n., medial 1/2 is ulnar n.

- Flexes distal phalanges (not pullux), assists w/flexion of the hand at wrist

Question 8

Pronator quadratus m. innervation and action?

Answer 8

• Median n.

- Pronates forearm

Question 9

Extensor carpi radialis longus m. innervation and action?

Answer 9

• Radial n.

- Extends and abducts hand at wrist

Question 10

Extensor carpi radialis brevis m. innervation and action?

Answer 10

• Radial n.

- Extends and abducts hand at wrist

Question 11

Extensor digitorum m. innervation and action?

Answer 11

• Radial n.

- Extends digits (not hallux), assists in wrist extension

Question 12

Extensor digiti minimi m. innervation and action?

Answer 12

• Radial n.

- Extends 5th digit

Question 13

Extensor carpi ulnaris m. innervation and action?

Answer 13

• Radial n.

- Extends and adducts hand at wrist

Question 14

Anconeus m. innervation and action?

Answer 14

• Radial n.

- Assists triceps in extending elbow, abducts ulna in pronation

Question 15

Abductor pollicis longus m. innervation and action?

Answer 15

• Radial n.

- Abduct and extend thumb at carpo-metacarpal joint

Question 16

Extensor pollicis brevis m. innervation and action?

Answer 16

• Radial n.

- Extends proximal phalanx of thumb at carpo-metacarpal joint

Question 17

Extensor indicis m. innervation and action?

Answer 17

• Radial n.

- Extends index finger (2nd digit), helps extend hand at wrist

Question 18

What tendons define the anatomical snuff box?

Answer 18

Abductor pollicis longus and extensor pollicis brevis tendons laterally and extensor pollicis longus tendon medially

Question 19

What m. of the forearm does the radial a. run under for most of its journey distally?

Answer 19

Brachioradialis m.

Question 20

What vessels/nerves enter the hand via the Canal of Guyon?

Answer 20

Ulnar a. and ulnar n.

Question 21

The median n. enters the forearm b/w the heads of what m.? Which mm. does the medial n. continue to run b/w?

Answer 21

• Pronator teres m.

- Flexor digitorum superficialis and flexor carpi radialis mm.

Question 22

The anterior interosseous n. branches from what nerve?

Answer 22

Median n.

Question 23

The ulnar n. enters the forearm behind what boney feature and then pierces what muscle?

Answer 23

• Medial epicondyle

- Flexor carpi ulnaris m.

Question 24

What m. of the forearm does the superficial branch of the radial a. run under for most of its journey distally?

Answer 24

Brachioradialis m. (for distal 1/3 of journey, it crosses to dorsum)

Question 25

What m. of the forearm does the deep branch of the radial n. (posterior interosseous n.) pass through?

Answer 25

Supinator m. (hint: deep penetration needed to kill supinator)