muscle - facial expression

  1. frontalis epicranius
    • origin: epicranial aponeurosis 
    • insertion: skin of eyebrows and root of nose 
    • action: with aponeurosis fixed raises the eyebrows (in surprise). Wrinkles forehead skin horizontally.
  2. occipital belly of epicranius
    • origin: occipital and temporal bones 
    • insertion: epicranial aponeurosis 
    • action: fixes aponeurosis and pulls scalp posteriorly
  3. orbicularis oris
    origin: arises indirectly from maxilla and mandible; fibers blend with fibers of other facial muscle associated with the lips

    insertion: encircles mouth; inserts into muscle and skin at angles of mouth

    action: closes lips; purses and protrudes the lips; kissing and whistling muscle
  4. zygomaticus major
    Origin: zygomatic bone

    Insertion: skin and muscle at corner of mouth 

    Action: raises lateral corners of mouth upward (smiling)
  5. Buccinators
    Origin: molar region of maxilla 

    Insertion: orbicularis oris 

    action: compresses check (whistling and sucking); trampoline-like action holds food between teeth during chewing; draws corners of mouth laterally; well developed in nursing infants
  6. platysma
    origin: fascia of chest (over pectoral muscles and deltoid) 

    insertion: lower margin of mandible, and skin of muscle at corner of mouth 

    action: tenses skin of neck (during shaving); helps depress mandible; pulls lower lip back and down, producing downward sag of mouth
  7. orbicularis oculi
    origin: frontal and maxillary bones and ligaments around orbit 

    insertion: tissue of eyelid

    action: closes eye; various parts can be activated individually; produces blinking and squinting; draws eyebrows inferiorly
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muscle - facial expression