Unit 4 - Head and Neck: Muscles of Facial Expression - Mouth and Neck (Ex. III)

Question 1

orbicularis oris

Answer 1

O: deep surface of skin; S - maxilla (M plane); I - mandible
I: mucous membrane of lips
Inn: facial n. (CN VII) branch
A: acts as oral sphincter - compresses and protrudes lips (whistling, sucking, kissing); resists distension (when blowing)

Question 2

buccinator

Answer 2

O: mandible; alveolar processes of maxilla and mandible; pterygoid mandibular raphe
I: angle of mouth; orbicularis oris
Inn: facial n. (CN VII) branch
A: presses cheek against molar teeth, working with tongue to keep food between occlusal surfaces and out of oral vestibule; expels air from oral cavity/resists distension when blowing; unilaterally draws mouth to one side