X-Ray cephalometric measurement has been conducted on a total of 107 orthodontic patients who visited our clinic and were diagnosed as having the so-called reversed occlusion. Figures obtained from the measurement were studied by plotting them on the diagrams (Fig. 3 to Fig. 19) of the standard deviations made from the Japanese subjects having the normal occlusion in our laboratory, and tables of distribution of the figures (Table 2 and Table 4) on the standard deviation diagrams were made for the comparative study. The results were summarized as follows : 1. In a majority of the overjet patients (50 to 70%), there were clearly seen regression of the upper facial region, maxillar region, maxillar region and the incisal margin of upper frontal teeth. 2. Migration of the mandible toward mesial direction was less frequently seen in those persons than was expected (10-15%). 3. In a majority of the patients amounting to 60 to 70% of the total, the distance between C and A' points of the maxillar was shorter than that found in persons having the normal occlusion. 4. 30 to 40% of the patients showed relatively larger distance between the points D and B against the magnitude of the mandibular dental arch. 5. Hyperplastic development at the frontal margin of the facial skull in the vertical direction in one hand and hypoplastic development in the vertical direction at the posterior margin of the facial skull on the other hand, were presumed to be present respectively in those persons in approximately 10 to 12% of the total. 6. There were also found in 30 to 50% of those patients considerable widening of the gonial angle.

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