The oral cavity (mouth) is the first part of the alimentary canal where food undergoes preliminary breakdown. It consists of the vestibule (between the lips/cheeks externally and the gums/teeth internally) and the oral cavity proper which is bounded by the teeth/gums, palate and tongue. It opens posteriorly into the oropharynx via an area known as the fauces.
Lateral walls
The lateral walls of the oral cavity are formed by buccinatoron each side, which is continuous with the superior constrictor at the pterygomandibular raphé (which runs between the medial pterygoid plate of the sphenoid and the mandible posterior to the mylohyoid ridge).
The the palatoglossusand palatopharyngeus muscles lie medial to the raphé and dominate the posterior border of the oral cavity. They respectively connect the tongue and pharynx to the palate and are covered by mucous membrane. Since the palatine tonsils lie between the muscles, they also known as the tonsillar pillars.
Floor
The mylohyoid muscles form a sling that marks the floor of the oral cavity. They are attached to the inner surfaces of the mandible and the hyoid bone, plus to each other at a midline raphé. Each has a free posterior border and are supplied by the nerve to mylohyoid, a branch of the inferior alveolar nerve from CN Vc.
MedMule 