part of part_of mouth oral cavity Anatomical cavity at the start of the digestive tract that that is enclosed by the mouth. The boundaries and contents vary depending on the species. In vertebrates, the boundaries are the oral opening, the cheeks, the palate and (if present) the palatoglossal arch - if this is not present then the mouth and pharynx form the oropharyngeal cavity. The buccal cavity contains the teeth, tongue and palate (when present) bucca buccal cavity cavity of mouth anatomical cavity