Studies on Growth of Pelvic Cavity by Radiographic Measurements

Abstract

Female pelvis, as the most important part of maternity, has repeatedly studied not only in Japan but in foreign countries, but few with the research from the point of view of relative growth throughout thewhole ages till maturity. This study of 1543 normal pelvis, sampled at random by sex, year-age (month-age in infancy), through the ages between 1 month and 17 years, was attempted to clarify the developmental changes of pelvic cavity by means of stochastical analysis on the radiographic measurements.
The results obtained are as follows.
(1) The pelvic cavity was found to become larger with the age advanced, and to show a particularly rapid. growth for three months after birth, between the ages of 1 and 4 years, and also in the puberty.
(2) Sexual differences of pelvic cavity were observed already in the infancy, that is, the upper structure in males and the lower structure in females were greater than those in opposite sex. After 10 years old, the growth of pelvic cavity in females was remarkable and in the puberty every parts of the cavity measured in females was greater than that in males.
(3) The investigation on relative growth between each parts of the pelvic cavity measuied in this study revealed that in the early infancy the maximum distance between both obturator-foramina increased most rapidly while the distance of Wollenberg's Y-cartilage-line did eminently in the later infancy and also in the puberty. The growth of breadth of the cavity was superior to that of the height in the infancy, while after that the latter became superior to the former ; in the puberty the both were almost of the same increase from the point of view of relative growth.
(4) The growth of the pelvic cavity had so close relationship to that of the pelvis that the coefficients of correlation between them gave very high possitive values.