Muscles of facial expressions Flashcards
Head & neck skeletal muscles (Action/ Origin/ Insertion/ Innervation)
Action-muscle fibers shorten & contract and are controlled by nerves
Origin-end of the muscles attached to the least movable structure
Insertion-end of the muscle attached to the more movable structure
sternocleidomastoid Muscle (Action/ Origin/ Insertion/ Innervation)
ORIGIN & INSERTION
Originates from the clavicle and sternum
Inserts on mastoid process of temporal bone on both sides
ACTION
Contraction of one side bends the head to that side
Contraction of both muscles bows the head
INNERVATION
Cranial nerve XI (accessory nerve)
Trapezius muscle (Action/ Origin/ Insertion/ Innervation)
ORIGIN & INSERTION Originates from occipital bone & cervical and thoracic vertebrae Inserts on clavicle and scapula ACTION Lifts clavicle & scapula; shrugs shoulders INNERVATION Cranial nerve XI (accessory) Third & fourth cervical nerves
Muscles of facial expression
Innervated by cranial nerve VII (facial nerve)
Responsible for functions related to facial expression (emotions) & lip movement for speech
Epicranial Muscle action
Elevates the eyebrow & scalp; look of surprise
Orbicularis oculi (Origin/ Insertion/ Action)
ORIGIN & INSERTION:
Originates on the orbital rim, nasal process of frontal bone, frontal process of maxilla
Inserts into skin at the lateral canthus of the eye
ACTION:
closes the eyelid; causes squinting
functions to protect & moisten the eye
Corrugator supercilii (Origin/ Insertion/ Action)
ORIGIN & INSERTION
Originates on the frontal bone in the supraorbital region
Inserts into skin of eyebrow
ACTION: draws eyebrow medially & downward
Orbicularis oris (Origin/ Insertion)
ORIGIN & INSERTION
Encircles mouth between skin and labial mucosa; no bony attachment
Inserts skin of lips at labial commissure; upper lip at the philtrum
Orbicularis oris Action
Pressing lips together
Tightening and thinning (pursing lips)
Rolling inward toward teeth (grimacing)
Thrusting outward (pouting & kissing)
Buccinator (Origin/ Insertion)
Originates on maxilla, mandible, and pterygomandibular raphe
Inserts into orbicularis oris at the angle of the mouth
Buccinator action
Pulls the mouth laterally, compressing the cheek
Aids in keeping food on chewing surfaces of teeth
In infants, provides suction for nursing
“trumpet muscle”
Risorius (Origin/ Insertion)
Originates from platysma and fascia of masseter muscle
Inserts at orbicularis oris at angle of mouth
Risorius Action
Stretches lips laterally, widening mouth
Levator labii superioris (Origin/ Insertion)
Originates from infraorbital rim of maxilla
Inserts into skin of upper lip
Levator labii superioris Action
Elevates upper lip
Levator labii alaeque nasi (Origin/ Insertion)
Originates from frontal process of maxilla
Inserts into skin at ala of nose & upper lip
Levator labii alaeque nasi Action
Elevates upper lip & ala of nose; dilates nostrils, “sneering expression”
Zygomaticus major (Origin/ Insertion)
Originates from zygomatic bone, lateral to zygomaticus minor
Inserts into skin at labial commissure, in and around orbicularis oris
Zygomaticus major Action
Pulls angle of the mouth laterally; smile
Zygomaticus minor (Origin/ Insertion)
Medial to zygomaticus major
Originates on body of zygomatic bone
Inserts into skin upper lip adjacent to insertion of levator labii superioris
Zygomaticus minor Action
Elevates upper lip
Assists in smiling
Levator anguli oris (Origin/ Insertion)
Deep to zygomaticus major & minor
Originates in canine fossa of maxilla
Inserts at skin of labial commissure
Levator anguli oris Action
Elevates corner of the mouth, assists in smiling
Depressor anguli oris (Origin/ Insertion)
Originates on inferior border of mandible
Inserts into skin at labial commissure
