PHA618 LAB: Muscular System

frontalis

draws scalp anteriorly; raises eyebrows; wrinkles forehead

occipitalis

draws scalp posteriorly

temporalis

for mastication; elevates mandible and closes the jaw

orbicularis oris

closes the mouth and puckers the lips

orbicularis oculi

closes the eye

buccinator

for mastication; compresses cheeks (as in blowing or whistling)

masseter

for mastication; raises jaw

sternocleidomastoid

both muscles: flex head; one muscle: rotates head toward the opposite shoulder

trapezius

extends the head and rotates the scapula

levator labii superioris

elevates the upper lip

zygomaticus major

raises the angle of the mouth (as in smiling)

zygomaticus minor

elevates the upper lip and exposes maxillary teeth

depressor anguli oris

depresses the angle of the mouth

medial pterygoid

raises the jaw

lateral pterygoid

lowers the jaw

platysma

depresses the mandible

trapezius

extends head and scapula

levator scapula

raises scapula

rhomboideus

retracts the scapula

Latissimus dorsi

extends the shoulders and adducts arm

gluteus medius

abducts the thigh and medially rotates it

gluteus maximus

facilitates extension at hip joint

teres major

extends the shoulders

supraspinatus

abducts the arm

infraspinatus

extends and rotates arm

external intercostals

expand the thorax

internal intercostals

compress the thorax

pectoralis major

controls the movement of the arm; adducts and medially rotates arm

pectoralis minor

depresses the scapula

serratus anterior

protracts the scapula

external abdominal obliques

compresses the abdomen

internal abdominal obliques

compresses the abdomen

rectus abdominis

flexes vertebral and column increases the pressure of the abdomen

transverse abdominal

compresses the abdomen

deltoid

abducts the arm; flexes and extends shoulders

biceps brachii

flexes the elbow and supinates the arm

brachialis

flexes arm

brachioradialis

flexes forearm (synergist of brachialis)

extensor carpi radialis longus

extends and abducts the wrist

extensor digitorum

extends fingers and flares or adducts fingers

extensor carpi ulnaris

extends and adducts the wrist

flexor carpi ulnaris

flexes and adducts the hand at wrist joint

palmaris longus

weakly flexes the hand at wrist joint

flexor carpi radialis

flexes the wrist and abducts the hand

pronator teres

pronates the forearm

biceps femoris

extends the thigh and laterally flexes the knee

semitendinosus

extends the thigh, flexes the knee, and rotates the leg medially

semimembranosus

extends the thigh, flexes the knee, and rotates the leg medially

gastrocnemius

plantar flexes the foot

soleus

plantar flexes the foot

peroneus/fibularis

plantar flexes the foot and everts the foot

tibialis anterior

dorsiflexes the foot (prime mover) and inverts the foot

extensor digitorum longus

dorsiflexes the foot

plantaris

plantar flexes the foot and flexes leg at the knee joint

levator ani

constricts the anus, urethra, and vagina; resists increased intra-abdominal pressure; and supports fetal head during childbirth

ischiocavernosus

erection

bulbospongiosus

Male: aids in urine and semen expulsion, and erection of penis; Females: constricts vaginal orifice, and assists in the erection of the clitoris

superficial transverse perineus

stabilizes central tendon of perineum

coccygeus

supports pelvic viscera; resists intra-abdominal pressure; and pulls coccyx anteriorly after defecation or childbirth

scalenes

raise the ribs and expand the thorax