Answer
Buccinator ( trumpet) Muscle. This is the main muscle of the cheek.
Actions: It has several roles:
It directs food between molars
Pulls cheek back from between teeth--when mouth is being closed
Expels air and liquids
Work Step by Step
Origin: Alveolar processes on lateral sides of mandible and maxilla
Insertion: Obiculoris oris muscle, and submucosa of cheeks and lips
Innervation: Facial nerve ( CN VII).