Muscles of Facial Expression, and mastication
EQ: How do skeletal muscles, functioning as an organ, produce
movement of the skeleton, maintain posture and body position,
support soft tissues, guard entrances and exits, and maintain
body temperature?
Objective:
Explain how the name of a muscle can help to identify its
location, appearance, or function.
Identify the main axial muscles of the body together with their
origin, insertions and actions
Vocabulary:
Origin
Insertion
Action: flexion, extension, adduction, abduction, protraction,
retraction, elevation, depression, rotation, circumduction,
pronation, supination, inversion, eversion
Prime mover (agonist)
Antagonist
synergist
Muscles of Facial Expression and Mastication
Description: thin, flat bands
origins on facial bone or cartilage
insertion into dermis of skin, or fibrous tissue around the sphincter
muscles of mouth or eye
5 groups:
1. Epicranial: occipitofrontalis – moves the scalp ; separated by
GALEA (helmet) APONEUROTICA
2. Orbital : orbicularis oculi, corrugators supercillii
3. Nasal group: nasalis, procerus
4. Oral group: orbicularis oris, zygomaticus major/minor, risorius,
buccinators , platysma
5. Ear group: auricular muscles
GENERAL FUNCTION: move the skin – facial expressions
MUSCLES:
1. Frontalis: raises eyebrows:
a. Insertion: skin around eye
2. Occipitalis – puls scalp posteriorly
b. Insertion: epicranial aponeurosis
3.Orbicularis oculi: closes eye
c. Insertion: eyelid
4.Orbicularis oris: closes and protrudes lips
d. Insertion: skin at corner of mouth
5.Buccinator: compresses cheeks as in whistling(deep to
zygomaticus and masseter) aids in mastication
e. Insertion: orbicularis oris
6. Zygomaticus: raises corners of mouth
a. Insertion: skin and muscle of corner of mouth
7. Procerus: flare nostrils
a. Insertion: aponeurosis at bridge of nose/forehead
8. Nasalis: compresses bridge of nose, raises corner of nostril
a. Insertion: bridge of nose
9. Risorius: from latin to laugh – superior to buccinators(wide band)
risorius is thin band - “ qui ridet tandem, ridet bene
a. Insertion: angle of mouth
10.
Platysma: tenses skin of neck, depresses mandible
a. Insertion: mandible
MUSCLES OF MASTICATION aka chewing
11.
Masseter: closes mouth
a. Insertion: mandible
12.
Temporalis: occupies most of temporal bone, synergist to
masseter
a. Insertion: mandible(coronoid process)
13.
Sternocleidomastoid: primary muscle of neck that moves
the head
a. Insertion: mastoid process of temporal bone
14.
Pterygoids: elevate, protract, and or move mandible to
either side (lateral pterygoids: transverse from sphenoid to
medial surface of condylar process medial pterygoids: rectus
from inferior surface of sphenoid to medial surface of ramus of
mandible
a. Insertion: medial surface of mandible
b. Origin – inferior processes of sphenoid
c. These muscles are deep to masseter and buccinators
Muscles of the cranium
15.
Frontalis: raises eyebrows, wrinkles forehead
a. Insertion: skin of eyebrow and bridge of nose
16.
Occipitalis: tenses and retracts scalp
a. Insertion: epicranial aponeurosis
*Palatal muscles: elevate the soft palate and lateral walls of pharyngeal
wall, AND pulls open entrance to auditory tube: thus, swallowing
repeatedly while ascending in airplane – relieves pressure
CLOSURE:
If you were contracting and relaxing your masseter, what activity would
you be participating in?
Which facial muscle would you expect to be well developed in the
nursery rhyme character “Georgie Porgie” ?