Abstract
As a basis for analysing the mandibular movement and occlusion utilizing diagrams drawn in actual dimensions or their like figures, seven horizontal reference planes were compared. Anatomical reference points on the skull were plotted in a sagittal plane in actual dimensions taken from the average bony data of the Japanese. Horizontal reference planes were drawn on the figure according to their definitions. Angles between each couple of reference planes were measured on the figure. Among them, a value of 11.8° was obtained for the angle between the Frankfort plane and the Camper's plane defined by Gysi.
