In human anatomy, the mouth is the first portion of the alimentary canal that receives food and produces saliva.

[2] The oral mucosa is the mucous membrane epithelium lining the inside of the mouth.

The lips mark the transition from mucous membrane to skin, which covers most of the body.

[3] The oral cavity is bounded at the sides and in front by the alveolar process (containing the teeth) and at the back by the isthmus of the fauces.

The posterior border of the oral cavity (ie, junction between the oral cavity and the oropharynx) includes the junction of the hard palate and the soft palate superiorly, the circumvallate papillae of the tongue inferiorly, and the retromolar trigone.

The posterior superior alveolar nerve supplies the gingiva on the facial aspect of the maxillary molar teeth.

The nasolabial folds are the deep creases of tissue that extend from the nose to the sides of the mouth.

One of the first signs of age on the human face is the increase in prominence of the nasolabial folds.