Muscle actions

Question 1

buccinator

Answer 1

draws corners of mouth laterally; compresses cheek (as in sucking and whistling), holds food between teeth while chewing, well developed in nursing infants

Question 2

Corrugator Supercilii

Answer 2

draws eyebrows together and inferiorly; wrinkles skin of forehead vertically (as in frowning)

Question 3

Depressor Anguli oris

Answer 3

zygomaticus antagonist; draws corners of mouth downward and laterally

Question 4

Depressor labii Inferioris

Answer 4

Draws lower lip inferiorly (pout)

Question 5

Frontal Belly

Answer 5

with aponeurosis fixed, raises the eyebrows (as in surprise); wrinkles forehead skin horizontally

Question 6

Genioglossus

Answer 6

primarily protrudes tongue, but can depress or act in concert with other extrinsic muscles to retract tongue

Question 7

Hyoglossus

Answer 7

depresses tongue; draws its sides downward

Question 8

Lateral Pterygoid

Answer 8

protrudes mandible (pulls it anteriorly); provides forward sliding and side to side grinding movements of the lower teeth

Question 9

Levator Labii Superioris

Answer 9

opens lips; raises and furrows the upper lip

Question 10

Masseter

Answer 10

prime mover of jaw closure; elevates mandible

Question 11

Medial Pterygoid

Answer 11

synergist of temporalis and masseter muscles in elevation of the mandible; acts with the lateral pterygoid muscle to protrude mandible and to promote side to side (grinning) movements

Question 12

Mentalis

Answer 12

protrudes lower lip; wrinkles chin

Question 13

Occipital Belly

Answer 13

fixes aponeurosis and pulls scalp posteriorly

Question 14

Orbicularis Oculi

Answer 14

protects eyes from intense light and injury; various parts can be activated individually; produces blinking, squinting, and draws eyebrows inferiorly

Question 15

Orbicularis Oris

Answer 15

Closes lips; purses and protrudes lips; kissing and whistling muscle

Question 16

Platysma

Answer 16

helps decrease mandible; pulls lower lip back and down, i.e., produces downward sag of mouth; tenses skin of neck (ex; during shaving)

Question 17

Risorius

Answer 17

draws corner of lip laterally; tenses lips; synergist of zygomaticus

Question 18

Styloglossus

Answer 18

retracts and elevates tongue

Question 19

Temporalis

Answer 19

closes jaw; elevates and retracts mandible, synergist of pterygoids in side- to- side movements, maintains position of the mandible at rest

Question 20

Zygomaticus

Answer 20

raises lateral corners of mouth upward (smiling muscle)