What is the distance of the line of lip closure from the base of the nose to the base of the chin?

The distance of the line of lip closure from the base of the nose to the base of the chin is typically represented as approximately one-third of the total distance between these two anatomical landmarks. This proportion reflects a common measurement used in various fields, including orthodontics and facial esthetics, to assess lip position relative to other facial features.

The measurement of one-third indicates that if you were to measure the vertical distance from the base of the nose to the base of the chin, the point of lip closure would be positioned at roughly one-third of that distance down from the base of the nose. This concept is rooted in the principles of facial symmetry and proportionality, which are foundational in both aesthetic and functional considerations in dental and facial reconstructive practices.