Muscles Acting on the Forearm and Hand

Question 1

Brachialis

Answer 1

O- distal humerus; I- coronoid process of ulna

Action- Flexes forearm

Question 2

Biceps brachii (short & long heads)

Answer 2

O- long head (more lateral): lip of glenoid cavity; short head: coracoid process; I- radial tuberosity (via common tendon)

Action- flex and supinate forearm

Question 3

Brachioradialis

Answer 3

O- distal humerus; I- radial styloid process

Action- flexes forearm

Question 4

Triceps brachii

Answer 4

O- long head: infraglenoid tubercle of scapula; lateral & medial heads- posterior shaft of humerus; I- olecranon of ulna (via common tendon)

Action- prime mover of forearm extension

Question 5

Flexor carpi ulnaris

Answer 5

O- medial epicondyle of humerus & olecranon of ulna; I- pisiform, hamate, metacarpal V
(location- anterior forearm)
Action- flexes and adducts hand

Question 6

Palmaris longus

Answer 6

O-medial epicondyle of humerus; I- palmar fascia (or palmar aponeurosis)
(location-anterior forearm)
Action- tenses the palmar fascia

Question 7

Flexor carpi radialis

Answer 7

O- medial epicondyle of humerus; I- metacarpals II & III
(location-anterior forearm)
Action- flexes and abducts hand

Question 8

Pronator teres

Answer 8

O-medial epicondyle of humerus; I- lateral radius
(location-anterior forearm)
Action- pronates forearm

Question 9

Extensor carpi ulnaris

Answer 9

O- lateral epicondyle of humerus; I- metacarpal V
(location-posterior forearm)
Action- extends and adducts hand

Question 10

Extensor digitorum

Answer 10

O- lateral epicondyle of humerus; I- distal phalanges 2-5
(location-posterior forearm)
Action- extends fingers

Question 11

Extensor carpi radialis (longus & brevis)

Answer 11

O- lateral epicondyle of humerus; I- metacarpal II (longus) & III (brevis)

Action- extends and abducts hand