Vertical features: The typical face can be divided into the following thirds:
(1) distance from hairline to plane through the superior extent of the eyes (if the person is bald or has receding hair, then use the point where hairline would be if the person had normal hair).
(2) distance from the superior extent of the eyes to the plane through the base of the nostrils
(3) distance from the base of the nostrils to the chin
In the lower third of the face:
(1) The distance from the base of the nose to the philtrum of the upper lip (the v-shaped indent in the midline) with the mouth closed and horizontal should be one third of the distance to the chin.
(2) The commissure height from the corners of the mouth to the plane through the base of the nostrils should be equal to the distance from the philtrum to the base of the nostrils.
(3) The distance from the line of mouth closure to the chin should be two-thirds of the lower third height.
(4) The ratio of these distances is expressed as 1/3 : 2/3.
Sagittal facial proportions:
(1) The frontal view of the face from outer edge of one ear to the other can be separated into 5 vertical sagittal planes, each approximately the width of the eye in the horizontal plane.
(2) The inner canthal distance should be about one eye width (half on each side of the midline).
(3) The distance from the outer canthus of the eye to the outer edge of the ear should be 1 eye width.
