These proportions are not exact or to be arbitrarily followed.
Drawing the Human Figure. When drawing the head, whether in profile or three-quarter view, avoid making the
facial line too upright. There can be no rigid rule regarding this or any other part of the human figure, on account of the variance of different persons. The degree of difference is even greater if we consider racial variances.
Making the features too small is a common error. Sometimes, however, the error is in the opposite direction, especially in respect to the eyes. They should not be made too large for the face. In drawing the normal eye, place the pupil slightly under the upper lid. Do not draw a line directly under the eyeball. If this is done, it is apt to give an impression of soreness to the eyes. Let the line indicating the upper line of the lower lid be a trifle distant from the eyeball. Eyelashes should be sparingly introduced. Eyebrows should not be too strongly demarked.
The ears should not be longer than the nose, and they should be level with it.
Things to Avoid. Do not maKe the mouth too small.
Do not make the space from the eyebrows to the top of the head too narrow.
Do not make finger nails too distinct or prominent.
Do not make goose-necks on your women nor bull-necks on your men and children.
Do not make the arms too long, unless you are making a caricature and wish to produce an ape-like effect.