Muscles Of Facial Expression - Regional Anatomy

Question 1

What are the muscles of facial expression?

Answer 1

• orbicularis oris
• biuccinator
• levator labii superioris
• levator labii superioris alaeque nasi
• zygomaticus major and minor
• levator anguli oris
• depressor labii inferioris
• mentalis
• platysma
• risorius

Question 2

Orbicularis oris

Answer 2

• large muscle - no skeletal origin - circumscribes the lips
• insertion for other muscles of facial expression
• action - opens and closes lips, presses teeth against lips, protrudes the lips (causes something to stick out)

Question 3

Buccinator

Answer 3

• pulls angle of mouth laterally (sideways) and assist mastication
• provides suction for suckling in children

Question 4

Levator labii superioris

Answer 4

• original - infraorbital rim of maxilla
• fibres run down into orbicularis oris
• action - raises upper lip

Question 5

Levator labii superioris alaeque nasi

Answer 5

• origin - frontal process of maxilla
• fibres inserted into orbicularis oris via philtrum and some into wing of nose
• action - elevates upper lip and wing of nose

Question 6

Zygomaticus major

Answer 6

• origin - zygomatic bone
• insertion - angle of mouth
• action - elevates and upper lip and pulls laterally

Question 7

Zygomatic minor

Answer 7

• origin - zygomatic bone
• insertion - upper lip
• action - contraction pulls upper lip upward

Question 8

Levator anguli oris

Answer 8

• origin - canine fossa of maxilla
• fibres - interested into lateral aspect of lip - angle of mouth
• action - elevates angle of mouth (smiling)

Question 9

Depressor anguli oris

Answer 9

• origin - lower border of mandible
• insertion - angle of the mouth
• action - pulls corner of lips downwards (sad face)

Question 10

Depressor labii inferioris

Answer 10

• origin - also lower border of mandible
• insertion - lower lip
• action -depresses lower lip exposing mandibular incisors

Question 11

Mentalis

Answer 11

• origin - mandible near midline insertion - skin of chin
• action - elevates skin of chin reducing depth or oral vestibule (dimpling of chin)

Question 12

Platysma and risorius

Answer 12

• platysma - runs from neck to mouth (shaving muscle)
• risorius - pulls corner of lip laterally (dimple)