Upper Extremity Actions and Innervations

Question 1

Pectoralis Major

Answer 1

A: adduct and medially rotate humerus
protract and depress scapula
flex humerus
extend humerus from flexed state
N: lateral and medial pectoral nerves

Question 2

pectoralis minor

Answer 2

A: stabilize scapula by protracting and depressing it against the thoracic wall
N: medial pectoral n

Question 3

subclavius m.

Answer 3

A: positions and depresses the clavicle
N: nerve to the subclavius m.

Question 4

serratus anterior m.

Answer 4

A: protracts the scapula which stabilizes it against thoracic wall, rotations glenoid cavity superiorly
N: long thoracic n.

Question 5

deltoid m

Answer 5

A: flexes and medially rotates the humerus (anterior part)
abducts the humerus (medial part)
extends and laterally rotates the humerus (posterior part)
N: axillary n.

Question 6

subscapularis

Answer 6

A: medially rotates and adducts the humerus
holds humerus head in glenoid cavity
N: upper and lower subscapular n.

Question 7

supraspinatus m.

Answer 7

A: abducts humerus (with deltoid) and holds humeral head in glenoid cavity
N: suprascapular n.

Question 8

infraspinatus m.

Answer 8

A: laterally rotates the humerus
holds humeral head in glenoid cavity
N: suprascapular n.

Question 9

teres minor m.

Answer 9

A: laterally rotates humerus
holds humeral head in glenoid cavity
N: axillary n.

Question 10

teres major m.

Answer 10

A: adducts and medially rotates humerus
N: lower subscapular n.

Question 11

biceps brachii m.

Answer 11

A: flexes humerus
flexes supine forearm
supinates the forearm
short head resists dislocation of shoulder
N: musculocutaneous n.

Question 12

coracobrachialis m.

Answer 12

A: flexes and adducts humerus
N: musculocutaneous n.

Question 13

brachialis m.

Answer 13

A: flexes forearm
N: musculocutaneous n.

Question 14

triceps brachii m.

Answer 14

A: extends forearm
long head resists dislocation of shoulder
N: radial n.

Question 15

aconeus

Answer 15

A: extends forearm (with triceps brachii)
stabilizes elbow joint
N: radial n.

Question 16

pronator teres m.

Answer 16

A: pronates and flexes forearm
N: median n.

Question 17

flexor carpi radialis m.

Answer 17

A: flexes forearm
flexes and abducts hand at the wrist
N: median n.

Question 18

palmaris longus m.

Answer 18

A: flex forearm
flex hand
tense palmar aponeurosis
N: median n.

Question 19

flexor carpi ulnaris m.

Answer 19

A: flex forearm
flex and adduct hand at wrist
N: ulnar n.

Question 20

flexor digitorum superficialis m.

Answer 20

A: flex forearm
flex hand at wrist
flex proximal and intermediate phalanges of digits 2-5 at metacarpophalangeal and proximal interphalangeal joints
N: median n.

Question 21

flexor digitorum profundus m.

Answer 21

A: flex hand at wrist
flex all phalanges of digits 2-5 at metacarpophalangeal, proximal, and distal interphalangeal joints
N: anterior interosseus n. (lateral part) and ulnar n. (medial part)

Question 22

flexor pollicis longus m.

Answer 22

A: flex hand
flex and abduct 1st metacarpal at the 1st carpometacarpal joint
flex both phalanges of pollux at intercarpal joint
N: anterior interosseus n

Question 23

pronator quadratus m.

Answer 23

A: pronate forearm
holds ulna and radius together
N: anterior interosseus n.

Question 24

brachioradialis m.

Answer 24

A: flex forearm (most force when forearm is midpronated)
N: radial n.

Question 25

extensor carpi radialis longus m.

Answer 25

A: extend and abduct hand at wrist N: radial nerve

Question 26

extensor carpi radialis brevis m.

Answer 26

A: extend and abduct hand at wrist N: deep radial n.

Question 27

extensor digitorum m.

Answer 27

A: extend hand at wrist extend all phalanges of digits 2-5 at the metacarpophalangeal, proximal, and distal interphalangeal joints N: posterior interosseus n.

Question 28

extensor digiti minimi m.

Answer 28

A: extend all phalanges of digit 5 at metacarpophalangeal, proximal, and distal interphalangeal joints N: posterior interosseus n.

Question 29

extensor carpi ulnaris m.

Answer 29

A: Extend and ADduct Hand at the Wrist N: posterior interosseus n.

Question 30

supinator m.

Answer 30

A: supinate forearm N: deep radial n.

Question 31

extensor indicis m.

Answer 31

A: extend hand at wrist extend 2nd digit N: posterior interosseus n.

Question 32

abductor pollicis longus m.

Answer 32

A: abduct hand at wrist abduct pollux at carpometacarpal joint N: posterior interosseus n

Question 33

extensor pollicis longus m.

Answer 33

A: abduct hand at wrist extend 1st metacarpal, proximal, and distal phalanges of pollux at carpometacarpal, metacarpophalangeal, and interphalangeal joint N: posterior interosseus n.

Question 34

extensor pollicis brevis m.

Answer 34

A: ABduct hand, Extend 1st Metacarpal and Proximal Phalanges of the Pollux at the Carpometacarpal and Metacarpophalangeal Joints N: posterior interosseus n.

Question 35

abductor pollicis brevis m.

Answer 35

A: abduct pollux aids in opposition N: recurrent branch of median n.

Question 36

opponens pollicis m.

Answer 36

A; oppose pollux | N: recurrent branch of median n

Question 37

flexor pollicis brevis m.

Answer 37

A: Flex 1st Metacarpal and Proximal Phalanges of the Pollux at the Carpometacarpal and Metacarpophalangeal Joints N: recurrent branch of median n. (superficial head) and deep ulnar n. (deep head)

Question 38

adductor pollicis m.

Answer 38

A: adduct pollux N: deep ulnar n.

Question 39

abductor digiti minimi m.

Answer 39

A: abduct 5th digit N: deep ulnar n.

Question 40

flexor digiti minimi brevis m.

Answer 40

A: flex proximal phalanx of 5th digit N: deep ulnar n.

Question 41

opponens digiti minimi m.

Answer 41

A: oppose 5th digit N: deep ulnar n.

Question 42

1st and 2nd lumbrical m.

Answer 42

A: Flex Proximal Phalanges of the 2nd and 3rd Digits at the Metacarpophalangeal Joint Extend Intermediate and Distal Phalanges of the 2nd and 3rd Digits by tightening extensor expansion N: median n.

Question 43

3rd and 4th lumbrical m.

Answer 43

A: Flex Proximal Phalanges of the 4th and 5th Digits at the Metacarpophalangeal Joint Extend Intermediate and Distal Phalanges of the 4th and 5th Digits by tightening extensor expansion N: deep ulnar n.

Question 44

dorsal interossei m.

Answer 44

A: abduct digits 2-4; flex proximal phalanges at the metacarpophalangeal joint extend intermediate and distal phalanges by tightening extensor expansion N: deep ulnar n.

Question 45

palmar interossei m.

Answer 45

A: ADduct 2nd, 4th and 5th Digits flex Proximal Phalanges of the 2nd, 4th and 5th Digits at the Metacarpophalangeal Joint Extend Intermediate and Distal Phalanges of the 2nd, 4th and 5th Digits by tightening extensor expansion N: deep ulnar n.