BIO 201: Chapter 3.4 Appendicular Skeletal Muscles - Upper Extremities

deltoid muscle

superficial, caps the shoulder

• flexes, extends, abducts, medially and laterally rotates arm

coracobrachialis muscle

most medial and deep arm muscle

• flexes and medially rotates arm

latissimus dorsi muscle

superficial and posterior

• extends, adducts, and medially rotates arms

• primer mover of the shoulder joint along with pectoralis major muscle

pectoralis major muscle

superficial

• flexes, adducts, and medially rotates arm

• prime mover of the shoulder joint along with latissimus dorsi muscle

pectoralis minor muscle

deep, has 3 heads that connect to a few superior ribs to the coracoid process

• works with the serratus anterior muscle to move the scapula bone anterior and laterally

serratus anterior muscle

superficial, originates from all or nearly all the ribs

• works with the pectoralis minor muscle to move the scapula bone anterior and laterally

supraspinatus muscle

located posterior, superior to the scapular spine

• aids the deltoid muscle in abduction of the arm

infraspinatus muscle

located posteriorly, inferior to the scapular spine

• rotates arm laterally

teres minor muscle

located posteriorly, inferior to the infraspinatus muscle but superior to teres major muscle

• rotates arm laterally

subscapularis muscle

located anteriorly, superficial to the subscapular fossa

• rotates arm medially

teres major muscle

intermediate and posterior, inferior to teres minor muscle

• extends and medially rotates arm

rotator cuff muscle group

supraspinatus muscle, infraspinatus muscle, teres minor muscle, and subscapularis muscle

• stabilize the glenohumeral joint

brachialis muscle

deep to biceps brachii muscle on anterior side

• prime mover of elbow flexion

biceps brachii muscle

superficial, large anterior bulge on upper arm, has 2 heads, attached to the biceps brachii aponeurosis

• rapid or forceful supination of forearm

triceps brachii muscle

superficial and posterior, has 3 heads (long head, lateral head, and medial head)

• prime mover of elbow extension along with the anconeus muscle

brachioradialis muscle

on the most lateral side of the forearm → lateral border that separates flexor and extensor side

• flexes the elbow

supinator muscle

deep, wraps around the radius bone, located near the elbow

• supinates the forearm and works with the biceps brachii muscle for supination

pronator teres muscle

small and proximal, near the antecubital region

• assists the pronator quadratus muscle with pronation

flexor carpi radialis muscle

its tendon attaches to the 2nd and 3rd metacarpals

• flexes the wrist anteriorly and aids in radial flexion of the wrist

palmaris longus muscle

weakly developed, sometimes absent, has long tendon attached to the palmar aponeurosis

• anchors skin and fascia of palmar region

palmar aponeurosis

superficial to the palm covering the tendons and muscle of the hand, attaches to the palmaris longus muscle if present (if absent it attaches to flexor retinaculum)

flexor carpi ulnaris muscle

its tendon attaches to the pisiform and hamate bones

• flexes the wrists anteriorly and aids in ulnar flexion of the wrist

flexor digitorum superficialis muscle

intermediate anterior forearm flexor muscle, has 4 tendons attached from the 2nd to 5th fingers

• flexes the wrists, knuckles, and fingers EXCEPT the thumb

flexor digitorum profundus muscle

deep and medial, has 4 tendons attached from the 2nd to 5th fingers

• flexes the wrists, knuckles, fingers, EXCEPT for the thumb

flexor pollicis longus muscle

lateral, has a long tendon attached to the thumb

• flexes the thumb

pronator quadratus muscle

small and squared muscle located near the wrist

• prime mover of forearm pronation

flexor retinaculum

wristband-like sheet where most tendons of the anterior forearm muscles pass under except for the tendon of the palmaris longus muscle that passes over it

• stabilizes the tendons and carpal region on the flexor side

thenar muscle group

mass of muscles located at the base of the thumb

• includes the flexor pollicis brevis and abductor pollicis brevis muscles

• concerned with the thumb’s precise movement

hypothenar muscle group

mass of muscles at the base of the little finger

• concerned with the little finger’s precise movements

lumbrical muscles

superficial muscles located at the palmar side of the metacarpals

• extends the knuckles

palmar interosseous muscles

deep muscles located at the palmar side of the metacarpals

• adducts the fingers and important for grip strength

anconeus muscle

superficial and deep posterior forearm extensor, small triangular muscle near the elbow

• extends the elbow, works with the triceps brachii muscle in elbow extension

extensor carpi radialis longus muscle

located next to and slightly overlaps with the brachioradialis muscle, tendon distally attaches to carpal bones

• extends the wrist and helps in radial flexion of the wrist

extensor carpi radialis brevis muscle

located very close to the extensor capri radialis longus muscle

• extends the wrist and helps in radial flexion of the wrist

extensor digitorum muscle

superficial wide muscle that has 4 tendons attached to the 2nd to 5th fingers

• extends the wrist, knuckles, fingers, EXCEPT for the thumb

extensor digiti minimi muscle

thin muscle that is very close to the extensor digitorum muscle

• extends the wrist and all joints of the little finger only

extensor carpi ulnaris muscle

located next to the flexor carpi ulnaris muscle

• extends the wrist when fist is clenched and helps in ulnar flexion of the wrist

abductor pollicis longus muscle

its tendon attaches to the thumb

• extends and abducts the thumb

extensor pollicis brevis muscle

its tendon attaches to the thumb

• extends the thumb and its knuckle

extensor pollicis longus muscle

its tendon sticks out and attaches to the thumb

• extends, adducts, and laterally rotates the thumb

extensor indicis muscle

its tendon attaches to the index finger

• extends the wrist and index finger

extensor retinaculum

wristband sheet where tendons of the posterior forearm muscles pass under it

• stablizes the tendons and carpal region on the extensor side

dorsal interosseous muscles

group of muscles located on the metacarpals of the band but on the dorsal side

• abduct the fingers and is important for grip strength