Muscles - Upper Limb

Question 0

teres minor

Answer 0

small muscle inferior to infraspinatus; rotator cuff

origin - lateral margin of scapula

insertion - greater tubercle of humerus (wraps around posteriorly)

action - laterally rotates the arm, stabilizes the humerus

Question 1

infraspinatus **

Answer 1

partially covered by deltoid and trapexius; rotator cuff muscle

origin - infraspinous fossa of scapula

insertion - greater tubercle of humerus

action - lateral rotation of humerus; helps hold head of humerus in glenoid cavity; stabilizes shoulder

Question 2

teres major

Answer 2

located inferiorly to infraspinatus; rotator cuff

origin - lateral margin of scapula

insertion - intertubercular sulcus of humerus (wraps around anterio-medially, between humerus and ribs)

action - extends, medially rotates, and adducts humerus; synergist of latissimus dorsi

Question 3

supraspinatus

Answer 3

obscured by trapezius; rotator cuff

origin - supraspinous fossa of scapula

insertion - greater tubercle of humerus

action - initiates abduction of humerus; stabilizes shoulder joint

Question 4

levator scapulae **

Answer 4

located at back and side of neck, deep to trapezius

origin - transverse processes of C1-C4

insertion - medial border of scapula superior to spine

action - elevates and adducts scapula; with fixed scapula, laterally flexes neck to same side

Question 5

rhomboideus major

Answer 5

beneath trapezius and inferior to levator scapulae; major = inferior

origin - spinous processes of T2-T5

insertion - medial border of scapula

action - stabilize scapula; pull scapula medially (retraction); rotate glenoid cavity downward

Question 6

rhomboideus minor

Answer 6

beneath trapezius and inferior to levator scapulae; minor = SUPERIOR

origin - spinous processes of C7 and T1

insertion - medial border of scapula

action - stabilize scapula; pull scapula medially (retraction); rotate glenoid cavity downward

Question 7

triceps bracii

Answer 7

sole, large flesh muscle of posterior humerus; 3 headed origin

origin - LONG head: inferior margin of glenoid cavity.
LATERAL head: posterior humerus
MEDIAL head: distal radial groove on posterior humerus

insertion - olecranon of ulna

action - powerful forearm extensor; antagonist of forearm flexors (brachialis and biceps brachii)

Question 8

biceps brachii

Answer 8

two headed bulging muscle

origin - SHORT head: coracoid process
LONG head: supraglenoid tubercle and lip of glenoid cavity; tendon of long head runs in intertubercular sulcus and within capsule of shoulder joint.

insertion - lateral aspect of olecranon of ulna

action - powerful flexion of elbow and supination of forearm (“turns the corkscrew and pulls the cork), weak arm flexor

Question 9

brachioradialis **

Answer 9

superficial muscle of lateral forearm; forms lateral boundary of antecubital fossa

origin - lateral ridge at distal end of humerus

insertion - base of radial styloid process

action - synergist in forearm flexion

Question 10

brachialis

Answer 10

immediately deep to biceps brachii

origin - distal portion of anterior humerus

insertion - coronoid process of ulna

action - major flexor of forearm

Question 11

pronator teres **

Answer 11

seen in superficial view between proximal margins of brachioradialis and flexor carpi radialis

origin - medial epicondyle of humerus and coronoid process of ulna

insertion - midshaft of radius

action - acts synergistically with pronator quadratus to pronate forearm; weak elbow flexor

Question 12

flexor carpi radialis **

Answer 12

superficial; runs diagonally across forearm

origin - medial epicondyle of humerus

insertion - base of metacarpals II and III

action - powerful flexor of wrist; abducts hand

Question 13

palmaris longus

Answer 13

small fleshy muscle with a long tendon; medial to flexor carpi radialis

origin - medial epicondyle of humerus

insertion - palmar aponeurosis; skin and fascia of palm

action - tenses skin and fascia of palm; flexes wrist (weak)

Question 14

flexor carpi ulnaris

Answer 14

superficial; medial to palmaris longus

origin - medial epicondyle of humerus and posterior surface of ulna

insertion - base of metacarpal; pisiform and hamate bones

action - powerful flexor of wrist, adducts hand

Question 15

flexor digitorum superficialis

Answer 15

deeper muscle (deep to other flexors), visible at distal end of forearm

origin - medial epicondyle of humerus, coronoid process of ulna, and shaft of radius

insertion - middle phalanges of fingers 2-5

action - flexes wrist and middle phalanges of fingers 2-5

Question 16

extensor digitorum **

Answer 16

superficial; medial to extensor carpi radialis brevis

origin - lateral epicondyle of humerus

insertion - by 4 tendons into phalanges of fingers 2-5

action - prime mover of finger extension; extends wrist; can flare (abduct) fingers

Question 17

extensor digit minimi

Answer 17

superficial; between extensor carpi ulnaris and extensor digitorum.

origin - lateral epicondyle of humerus

insertion - via tendon to 5th phalanx

action - extends wrist and little finger