Upper Arm Muscles

Question 1

triceps brachii long head

Answer 1

origin: inferior margin of glenoid cavity
insertion: olecranon of ulna
action: forearm extensor, antagonist of forearm flexors

Question 2

triceps brachii lateral head

Answer 2

origin: posterior humerus
insertion: olecranon of ulna
action: forearm extensor, antagonist of forearm flexors

Question 3

triceps brachii medial head

Answer 3

origin: inferior margin of glenoid cavity
insertion: olecranon of ulna
action: forearm extensor, antagonist of forearm flexors

Question 4

anconeus

Answer 4

origin: lateral epicondyle of humerus
insertion: lateral aspect of olecranon of ulna
action: abducts ulna during forearm pronation, synergist of triceps brachii in forearm extension

Question 5

biceps brachii short head

Answer 5

origin: coracoid process
insertion: radial tuberosity
action: flexion and supination of forearm

Question 6

biceps brachii long head

Answer 6

origin: supraglenoid tubercle and lip of glenoid cavity
insertion: radial tuberosity
action: flexion and supination of forearm

Question 7

brachioradialis

Answer 7

origin: lateral ridge at distal end of humerus
insertion: base of radial styloid process
action: flexion and supination of forearm

Question 8

brachialis

Answer 8

origin: distal portion of anterior humerus
insertion: coronoid process of ulna
action: flexor of forearm

Question 9

pronator teres

Answer 9

origin: medial epicondyle of humerus and coronoid process of ulna
insertion: midshaft of radius
action: synergist with pronator quadratus to pronate forearm

Question 10

flexor carpi radialis

Answer 10

origin: medial epidcondyle of humerus
insertion: base of metacarpal II and II
action: flexor and abductor of the hand

Question 11

palmaris longus

Answer 11

origin: medial epidcondyle of humerus
insertion: palmar aponeurosis
action: flexor and abductor of the hand

Question 12

flexor carpi ulnaris

Answer 12

origin: medial epidcondyle of humerus and olecranon and posterior surface of ulna
insertion: base of metacarpal V, pisiform and hamate bones
action: flexes and abducts of the hand

Question 13

flexor digitorum superficialis

Answer 13

origin: medial epidcondyle of humerus, coronoid process of ulna, shaft of radius
insertion: middle phalanges of fingers II-V
action: flexes hand and middle phanages of fingers II-V

Question 14

flexor pollicis longus

Answer 14

origin: anterior surface of radius and interosseous
insertion: distal phalanx of thumb
action: flexes thumb

Question 15

flexor digitorum profundus

Answer 15

origin: anteromedial surface of ulna. interosseous membrance and coronoid process
insertion: distal phalanges of fingers II-V
action: flexes distal phalanges

Question 16

pronator quadratus

Answer 16

origin: distal portion of anterior ulnar surface
insertion: anterior surface of radius, distal end
action: pronates forearm

Question 17

extensor carpi radialis longus

Answer 17

origin: lateral supercondylar ridge of humerus
insertion: base of metacarpal II
action: extends and abducts hand

Question 18

extensor carpi radialis brevis

Answer 18

origin: lateral epicondyle of humerus
insertion: base of metacarpal III
action: extends and abducts hand

Question 19

extensor digitorum

Answer 19

origin: lateral epicondyle of humerus
insertion: by 4 tendons into distal phalanges of fingers II-V
action: prime mover of finger extension

Question 20

extensor carpi ulnaris

Answer 20

origin: lateral epicondyle of humerus, posterior border of ulna
insertion: base of metacarpal V
action: extends and abducts hand

Question 21

extensor pollicis longus and brevis

Answer 21

origin: dorsal shaft of ulna and radius, interosseous membrane
insertion: base of distal phalanx of thumb and proximal phalanx of thumb
action: extend thumb

Question 22

abductor pollicis longus

Answer 22

origin: posterior surface of radius and ulna, interosseous membrane
insertion: metacarpal I and trapezium
action: abducts extend thumb

Question 23

supinator

Answer 23

origin: lateral epicondyle of humerus, proximal ulna
insertion: proximal end of radius
action: synergist of biceps brachii to supinate forearm, antagonist of pronator muscles

Question 24

infraspinatus

Answer 24

origin: infraspinous fossa of scapula
insertion: greater tubercle of humerus
action: lateral rotation of arm

Question 25

teres minor

Answer 25

origin: lateral margin of posterior scapula
insertion: greater tubercle of humerus
action: lateral rotation of arm

Question 26

supraspinatus

Answer 26

origin: supraspinous fossa of scapula
insertion: greater tubercle of humerus
action: initiates abduction of the arm

Question 27

subscapularis

Answer 27

origin: subscapular fossa
insertion: lesser tubercle of the humerus
action: medially rotates the head of the humerus

Question 28

teres major

Answer 28

origin: posterior surface at inferior angle of scapula
insertion: intertubercular sulcus of humerus
action: extend thumb, medially rotates, and adducts arm

Question 28

teres major

Answer 28

origin: posterior surface at inferior angle of scapula
insertion: intertubercular sulcus of humerus
action: extend thumb, medially rotates, and adducts arm

Question 29

deltoid

Answer 29

origin: lateral 1/3 of clavicle, acromion and spine of scapula
insertion: deltoid tuberosity of humerus
action: prime mover of arm abduction

Question 30

coracobrachialis

Answer 30

origin: coracoid process of the scapula
insertion: body of the humerus
action: flexion, adduction

Question 31

thenar

Answer 31

origin: scaphoid and trapezium
insertion: within the carpals and metacarpals of the hand
action: produce movement of the thumb