The oral cavity (or cavity of mouth, latin: cavitas oris) is the initial part of the digestive tract, where the food is received, saliva produced and the digestion process started.
The oral cavity begins at the border between the facial skin and the lips, has a roof formed by the palate, inner surface of the cheeks on the sides, and the floor of the mouth inferiorly. It leads into the pharynx, specifically, the oropharynx.
There are two parts of the oral cavity: the oral vestibule and the oral cavity proper. The oral vestibule is the area bounded externally by the lips and cheeks and internally by the teeth and gingiva. The oral vestibule is connected with the outer environment via the orifice of the mouth, which is surrounded by lips. The oral cavity proper is the part of the oral cavity behind the teeth, extending from the alveolar arches anteriorly and laterally to the entry into the oropharynx posteriorly.
The surfaces within the oral cavity are mostly lined with a mucosal membrane - the oral mucosa. The oral cavity is occupied by the tongue.