Abstract
Head circumference, head length, head breadth, auricular height and biacromial breadth were measured with 84 profoundly retarded adults living at home (39 males and 45 feamales), and the values were compared with those of 163 normal adults (82 males and 81 feamales) . Two values, cranial capacity and brain weight, were calculated by Lee-Pearson's formula and Gladstone's formula, respectively.
Each of the averaged value of the profoundly retarded persons was significantly lower than the corresponding value of the normal persons, but the standard deviations of these averages were significantly greater. Among the head length, head breadth and auricular height, the head length differed most remarkably between the retarded and normal persons.
Profoundly retarded persons were divided into three groups according to the degree of retardation : Group I, the most ; Group II, the second ; and Group III, the third profoundly retarded persons. In the head size measurements, the smallest averages were observed always in Group I and the largest in Group III. When all of the measured values in Groups I and II are compared with those of the normal persons, the values of the former was always found to be significantly smaller than those of the latter. There was no significant difference in the averages of the walues between Group III and the normal persons.
Both the biacromial breadth and the ratio of head size to biacromial breadth of profoundly retarded persons were significantly smaller than those of the normal persons.
