Standard Terminology for the Lips, Mouth, and Oral Region

The appearance of the lips varies with facial movement. Smiling and crying can alter dramatically the shape of the upper lip, as do pursing or pouting. Therefore, the lips must be assessed when the subject has a relaxed (neutral) face: the eyes are open, the lips make gentle contact, and the teeth are slightly separated. The neck, jaw, and facial muscles should not be stretched nor contracted, and the face should be positioned using the Frankfurt horizontal (a line joining the orbitale and the porion) [Farkas, [1981]]. A detailed description of the anatomic features of the lips, mouth, and oral region is available for reference.

The definitions are listed alphabetically based on the physical feature, not the modifier.