all the muscles innervated by the 7th cranial nerve (facial nerve)
- 1) The muscles are more developed in animals then humans.
- 2) Posterior auricular muscle
- * Pulls the ear back. Probably the best developed ear muscle.
- 3) Superior auricular muscle
- * Raises the ear.
- 4) Anterior auricular muscle
- * Pulls ear slightly forward.
- 1) Muscle- Occipitofrontalis (epicranius) is a paired muscle.
- 2) Forward movement causes a frown look.
- 3) Backward movement causes a surprise look.
- 1) Muscle- Platysma muscle.
- 2) There is some disagreement about its origin and insertion.
- 3) Inferior border of the mandible to just below the clavicle.
- Has 3 muscles.
- 1) Orbicularis Oculi muscle (has 2 parts) (Closes the eyelids)
- * Palpebral part (top) Eyelid.
- * Orbital part (bottom).
- 2) Corrugators muscle (bridge of the nose to lateral part of the eyebrow)
- * Pulls eyebrow medially and down. Ex. Frown
- 3) Procerus muscle (bridge of the nose to medial end of the eyebrow)
- * Pulls eyebrow at medial end down. Ex. Frown or Squint
- Has 2 muscles.
- 1) Dilator Naris
- * Pulls down on nostrils. Ex. Flare and Dilate
- 2) Compressor Naris
- * Causes nostrils to close or compress.
- 1) Influences:
- * Expression
- * Speech
- * Aids in mastication
- 2) Abnormal pressure causes:
- * Cheek biting
- * Lip biting
- * Lip compression (can cause teeth misalignment)
Muscle of the Mouth (10)
- 1) Orbicularis Oris
- * Circles the oral cavity in the tissue of the lip.
- * Causes �closes and compresses lip�.
- 2) Levator Labii Superioris
- * Elevates the upper lip.
- * Origin is just beneath the lower rim of the orbit.
- * Insert into the Orbicularis oris.
- 3) Zygomaticus Minor
- * Elevates upper lip.
- * Poorly developed muscle.
- * From the Zygomatic bone to the Orbicularis oris.
- 4) Zygomaticus Major
- * It is larger then the zygomatius minor.
- * Elevates the corner of the mouth as in a smile.
- * From the Zygomatic bone to the Orbicularis oris5)
- 5) Levator Anguli
- * Pulls the angles of the mouth up and toward the midline.
- * From the maxilla(below the infra orbital foramen) to the Orbicularis oris.
- * Lies deep to the levator labii superioris and the zygomaticus major and minor.
- 6) Depressor Labii Inferioris
- * Pulls lower lip down as in a pout.
- * From beneath the angles of the mouth to just below the inferior boarder of the mandible.
- 7) Depressor Anguli Oris
- * Pulls the corners of the mouth down.
- * The muscle fibers appear to be a continuation of the fibers of the Platysma.
- 8) Mentalis
- * Pulls skin of chin up
- .9) Buccinator
- * Probably the most important muscle of the mouth.
- * Involved in: 1) Facial expression 2) Mastication
- * When the muscle contracts, it pulls the corners of the mouth back and compresses the cheeks.
- * During chewing, the food is crushed and grounded between the molars.
- * Also referred to the accessory muscle of mastication.
- * Fibers run anteriorly.
- * Person with a stroke or Bell's palsy would have difficultly chewing, food would pile up in the buccal vestibule.
- 10) Risorius
- * Aids in smiling, but poorly developed.
- * Is a small muscle.
- * Inserts into the corner of the mouth.
- * Is an apparent continuation of the posterior fibers of the Platysma muscle.