Forearm Muscles

Question 1

Compartments of forearm muscles.

Answer 1

• anterior: flexors ￫ innervated by median nerve
• posterior: extensors ￫ innervated by radial nerve

Question 2

Muscles of the superficial layer of the anterior compartment of the forearm.

Answer 2

From lateral to medial:
* pronator teres
* flexor carpi radialis
* palmaris longus
* flexor carpi ulnaris
* flexor digitorum superficialis

Question 3

Muscles of the deep layer of the anterior compartment of the forearm.

Answer 3

• flexor digitorum profundus
• flexor pollicis longus
• pronator quadratus

Question 4

Muscles of the superficial layer of the posterior compartment of the forearm.

Answer 4

• brachioradialis
• extensor carpi radialis longus
• extensor carpi radialis brevis
• extensor digitorum
• extensor digiti minimi
• extensor carpi ulnaris

Question 5

Muscles of the deep compartment of the posterior layer of the forearm.

Answer 5

• abductor pollicis longus
• extensor pollicis longus
• extensor pollicis brevis
• extensor indicis
• supinator

Question 6

Pronator teres:
* Origin
* Insertion
* Action
* Innervation

Answer 6

O: supracondylar ridge of humerus+ coronoid process of ulna
I: lateral surface of radius
A: internal rotation of forearm
N: median n.

Question 7

Flexor carpi radialis:
* Origin
* Insertion
* Action
* Innervation

Answer 7

O: common flexor tendon of the elbow
I: palmar surface of base of 2nd metacarpal
A: wrist flexion
N: median n.

Question 8

Palmaris longus
* Origin
* Insertion
* Action
* Innervation

Answer 8

O: common flexor tendon of elbow
I: palmar aponeurosis
A: weak wrist flexion
N: median n.

Question 9

Flexor carpi ulnaris
* Origin
* Insertion
* Action
* Innervation

Answer 9

O:
* humeral head: common flexor tendon
* ulnar head: medial margin of olecranon
I: pisiform + hamate + 5th metacarpal bone
A: wrist flexion and forearm adduction
N: ulnar n.

Question 10

Flexor digitorum superficialis
* Origin
* Insertion
* Action
* Innervation

Answer 10

O:
* humerulnar head: medial epicondyle of humerus + coronoid process
* radial head: anterior border of radius
I: middle phalanxes of fingers 2 to 5
A: wrist and fingers flexion
N: median n.

Question 11

Flexor digitorum profundus
* Origin
* Insertion
* Action
* Innervation

Answer 11

O: anterior + medial surface of ulna and interosseous membrane
I: through 4 tendons that insert into bases of distal phalanxes 2 to 5
A: flexion of fingers
N: medial part by ulnar n.
lateral part by median n.

Question 12

Flexor pollicis longus:
* Origin
* Insertion
* Action
* Innervation

Answer 12

O: anterior surface of radius + interosseous membrane
I: base of distal phalanx of thumb
A: flexor of thumb
N: median n.

Question 13

Pronator quadratus
* Origin
* Insertion
* Action
* Innervation

Answer 13

O: anterior surface of medial ulna
I: distal border of radius
A: forearm pronator
N: interosseous n. (branch of median n.)

Question 14

Brachioradialis:
* Origin
* Insertion
* Action
* Innervation

Answer 14

O: lateral margin + lateral epicondyle of humerus
I: styloid process of radius
A: flexion of elbow
N: radial n.

Question 15

Extensor carpi radialis longus:
* Origin:
* Insertion:
* Action:
* Innervation

Answer 15

O: lateral supracondylar ridge of humerus + lateral intramuscular septum
I: base of 2nd metacarpal
A: extension + abduction of wrist
N: radial n.

Question 16

Extensor carpi radialis brevis:
* Origin
* Insertion
* Action
* Innervation

Answer 16

O: lateral epicondyle of humerus (common extensor tendon) + lateral intramuscular septum
I: base of 3rd metacarpal
A: extension + abduction of wrist
N: radial n.

Question 17

Extensor digitorum:
* Origin
* Insertion
* Action
* Innervation

Answer 17

O: lateral epicondyle of humerus (common extensor tendon)
I: 4 tendons that insert at the base of medial and distal phalanxes of fingers 2 to 5
A: extension of wrist + fingers
N: radial n.

Question 18

Extensor digiti minimi:
* Origin
* Insertion
* Action
* Innervation

Answer 18

O: common extensor tendon
I: digit 5
A: extension of little finger
N: radial n.

Question 19

Extensor carpi ulnaris:
* Origin
* Insertion
* Action
* Innervation

Answer 19

O: common extensor tendon + posterior border of ulna
I: base of 5th metacarpal bone
A: wrist extension
N: radial n.

Question 20

Abductor pollicis longus:
* Origin
* Insertion
* Action
* Innervation

Answer 20

O: posterior surface of shaft of ulna and radius + interosseous membrane
I: base of 1st metacarpal
A: wrist and thumb abduction
N: radial n.

Question 21

Extensor pollicis longus:
* Origin
* Insertion
* Action
* Innervation

Answer 21

O: posterior aspect of shaft of ulna + interosseous membrane
I: base of distal phalanx of thumn
A: extension of thumb
N: radial n.

Question 22

Extensor pollicis brevis:
* Origin
* Insertion
* Action
* Innervation

Answer 22

O: posterior surface of shaft of radius + interosseous membrane
I: base of proximal phalanx of thumb
A: extension of thumb
N: radial n.

Question 23

Extensor indicis:
* Origin
* Insertion
* Action
* Innervation

Answer 23

O: posterior surface of shaft of ulna + interosseous membrane
I: dorsal aponeurosis of 2nd finger
A: extension of pointer finger
N: radial n.

Question 24

Supinator:
* Origin
* Insertion
* Action
* Innervation

Answer 24

O: one head on lateral epicondyle of humerus; other head on ulna
I: lateral surface of proximal end of radius
A: lateral rotation of forearm
N: radial n.