Muscle actions Flashcards
buccinator
draws corners of mouth laterally; compresses cheek (as in sucking and whistling), holds food between teeth while chewing, well developed in nursing infants
Corrugator Supercilii
draws eyebrows together and inferiorly; wrinkles skin of forehead vertically (as in frowning)
Depressor Anguli oris
zygomaticus antagonist; draws corners of mouth downward and laterally
Depressor labii Inferioris
Draws lower lip inferiorly (pout)
Frontal Belly
with aponeurosis fixed, raises the eyebrows (as in surprise); wrinkles forehead skin horizontally
Genioglossus
primarily protrudes tongue, but can depress or act in concert with other extrinsic muscles to retract tongue
Hyoglossus
depresses tongue; draws its sides downward
Lateral Pterygoid
protrudes mandible (pulls it anteriorly); provides forward sliding and side to side grinding movements of the lower teeth
Levator Labii Superioris
opens lips; raises and furrows the upper lip
Masseter
prime mover of jaw closure; elevates mandible
Medial Pterygoid
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
Mentalis
protrudes lower lip; wrinkles chin
Occipital Belly
fixes aponeurosis and pulls scalp posteriorly
Orbicularis Oculi
protects eyes from intense light and injury; various parts can be activated individually; produces blinking, squinting, and draws eyebrows inferiorly
Orbicularis Oris
Closes lips; purses and protrudes lips; kissing and whistling muscle