Anatomy: Ch. 10 & 11- Muscular system- Axial and Appendicular skeleton

Epicranius (Occipitofrontalis)

Action: Pull the scalp forward and backward

Frontalis

Raises eyebrows; wrinkles forehead skin horizontally

Occipitalis

Pulls scalp posteriorly

Orbicularis Oculi

Closes the eye; blinking; squinting; draws eyebrows inferiorly

Zygomaticus (minor & major)

Raises lateral corners of mouth upward (smiling)

Risorius

Draws corners of lips laterally

Orbicularis Oris

Closes, purses, and protrudes lips (kissing and whistling)

Buccinator

Compresses cheek (whistling and sucking)

Platysma

Tenses skin of neck (shaving muscle)

Masseter

Prime mover of jaw closure; elevates mandible

Temporalis

closes jaw; maintains position of mandible at rest

digastric

opens mouth and depresses mandible

stylohoid

elevates and retracts hyoid

mylohyoid

Elevates hyoid bone and floor of mouth

sternohyoid

depresses larynx and hyoid bone

Sternothyroid

pulls larynx and hyoid bone inferiorly

omohyoid

depresses and retracts hyoid

sternocleidomastoid

flexes and laterally rotates head

scalenes

elevates first two ribs

spenius

extend and hyperextend neck

erector spinae

prime mover of back extension

iliocostalis (I)

Lateral; extend and laterally flex vertebral column

Longissimus (like)

intermediate: extend and laterally flex vertebral column; extends head and turns the face toward the same side

spinalis (spaghetti)

medial: extends vertebral column

external intercostals

pull ribs toward one another to elevate rib cage

internal intercostals

draw ribs together; depress rib cage

diaphragm

prime mover of inspiration; flattens on contraction

rectus abdominis

flex and rotate lumbar region of vertebral column

external and internal oblique

flex vertebral column and compress abdominal wall; trunk rotation and lateral flexion

transverse abdominis

compress abdominal contents

pectoralis minor

draws scapula forward and downward, with ribs fixed; draws rib cage superiorly, with scapula fixed

Serratus anterior

rotates scapula so that its inferior angle moves laterally and upward; prime mover to protract and hold scapula against chest wall

Subclavius

helps stabilize and depress pectoral girdle

trapezius

stabilizes, raises, retracts, depress, and rotates scapula

levator scapulae

elevates/adducts scapula

rhomboid major and minor

stabilize scapula

Pectoralis major

largest muscle; prime mover of arm flexion; roates arm medially; adducts arm

latissimus dorsi

prime mover of arm extension; arm adductor; medially rotates arm at shoulder; depress scapula

deltoid

prime mover of arm aBduction

teres major

NOT A ROTATOR CUFF; extends, medially rotates, and adducts humerus

subscapularis

chief medial rotator of humerus

supraspinatus

initiates aBduction at shoulder; stabilizes shoulder joint

infraspinatus

rotates humerus laterally

teres minor

ROTATOR CUFF; rotates humerus laterally

coracobrachialis

flexion and adduction of the humerus

tricepts brachii

powerful forearm extensor

anconeus

aBducts ulna during forearm pronation

biceps brachii

supinates forearm; flexion at elbow and shoulder

brachialis

a major forearm flexor

brachioradialis

lateral; synergist in forearm flexion

flexor and extensor retinacula

kepps tendons from jumping outward when the hand is hyperflexed or hyper extended

pronator teres

pronates forearm

flexor carpi radialis

powerful flexor of wrist; aBducts hand

palmaris longus

tenses skin and fascia of palm during hand movements

flexor carpi ulnaris

powerful flexor of wrist; adducts hand

flexor digitorium superficialis

flexion at middle phalanges of finder 2-5

extensor carpi radialis longus

extends wrist; aBducts wrist

extensor carpi radialis brevis

extends and aBducts wrist

extensor digitorium

prime mover of finger extension; extends wrist; aBduct fingers

extensor carpi ulnaris

extends wrist; adducts wrist

aBductor pollicis longus

aBducts and extends thumb; aBduction at wrist joint

extensor indicis

extends index finger

levator ani

supports and maintains position of pelvic viscera

Iliococcygeus & Pubococcygeus

tenses floor of pelvis, supports pelvic organs, flexes coccygeal joints, elevates and retracts anus

coccygeus

supports pelvic viscera and coccyx

external anl sphincter

closes the anal opening

deep transverse perineal muscle

supports pelvic organs

external urethral sphincter

constricts urethra

ischiocavernosus

retracts venous drainage and maintains erection of penis or clitoris

bulbospongiosus

empties male urethra

superficial transverse perineal muscle

stabilizes and strengthens centra tendon of perineum

iliacus

prime mover in thigh flexion and flexing the trunk

psoas major

same as iliacus; also lateral flexion of vertebral column

sartorius

flexes, aBducts and laterally rotates thigh; flexes knee

adductor longus

adductus, flexes, and medially rotates thigh

adductor brevis

adducts and medially rotates thigh

adductor magnus

adduction at the hip; anterior part medially rotates and flexes thigh; posterior part is a synergist of hamstrings in thigh extension

pectineus

adducts, flexes, and medially rotates thigh

gracilis

adducts and medially rotates thigh, flexes and medially rotates leg

quadricepts femoris

powerful knee extensor; arises from four heads; on front and sides of thigh

rectus femoris

extends knee and flexes thigh at hip

vastus lateralis

extends and stabilizes knee

vastus medialis

extends knee; inferior fibers stabilize patella

vastus intermedius

extends knee

tensor fasciae latae

steadies trunk on thigh by making iliotibial tract taut; flexes and aBducts thigh; rotates thigh medially; extension and lateral rotation at knee.

gluteus maximus

major extensor of thigh; aBduct the hip

gluteus medius

site for injections; aBducts and medially rotates thigh

gluteus minimus

aBducts and medially rotates thigh

piriformis

rotates extended thigh laterally; aBduction of hip

obturator externus and Internus

rotates extended thigh laterally; aBduction of hip

gemellus superior and inferior

rotates extended thigh laterally; aBduction of hip

quadratus femoris

rotates thigh laterally and stabilizes hip joint

biceps femoris

extend thigh and flexes knee; laterally rotates leg

semitendinosus

extends thigh at hip; flexes knee; medially rotates leg

semimembranosus

extends thigh and flexes knee; medially rotates leg

tibialis anterior

prime mover of dorsiflexion; inverts foot

extesnor digitorum longus

prime mover of toe (2-5) extension; dorsiflexes foot at ankle

fibularis tertius

dorsiflexes and everts foot

extensor hallucis longus

extends great toe; dorsiflexes at ankle

fibularis longus

plantar flexes and everts foot