lip begins from vermilion border and includes only vermiloin surface , that comes into contact with the opposing lip, both upper and lower lip joined at the commissures of the mouth.
buccal mucosa: it includes all the membrane lining of the inner surface of cheeks, anteriorly from oral commissure to retromolar gingiva posteriorly.
it is the mucosa overlying alveolar process of the maxilla, extending from upper gingival buccal sulcus to junction of the hard palate, the posterior margin is the upper end of the pterygopalatine arch.
It is the mucosa overlying alveolar process of mandible, which extend from lower gingival buccal sulcus to line of free mucosa of the floor of the mouth, posteriorly it extends to the ascending ramus of the mandible.
It is a semilunar space over the mylohyoid and hyoglossus muscles, extending from the inner surface of the lower alveolar ridge to the undersurface of the tongue. Its posterior boundary is the base of an anterior pillar of the tonsil.
It is the freely mobile portion of the tongue that extends anteriorly from the line of circumvallate papillae to the undersurface of the tongue at the junction of the floor of the mouth. It is composed of four areas: the tip, the lateral borders, the dorsum, and the undersurface ( ventral surface of the tongue)
It is the attached mucosa overlying the ascending ramus of the mandible from the level of the posterior surface of the last molar tooth to the apex superiorly, adjacent to the tuberosity of the maxilla.
It is the semilunar area , between the upper alveolar ridge and mucous membrane covering the palatine process of the maxillary palatine bones.