Chest Width-Hip Width Index. ∗

Abstract

In the human skeleton the relationship between chest width and hip width is constantly changing throughout the period of development from birth to maturity. At birth the chest width exceeds the hip width in both males and females. This difference increases during the first 18 months of life due to the higher growth rate of the chest width. During the period from 18 months to 2 1/2 years the rate of growth of the chest width is slowed down and that of the hip width is accelerated, resulting in the 2 measures becoming equal between 3 1/2 and 4 1/2 years. The chest width thereafter continues to grow at a slower rate than the hip width up to the age of puberty.

During the 7th year the growth rate of the hip width in the majority of females is more rapid than in the males. Thereafter hip width in the female exceeds that in the male and at the tenth year another spurt on the part of the female increases the difference. In order to express this changing relationship between hip and chest an index was used derived by dividing the chest width at any given age by the hip width. It was found that this index is above 100 in both males and females up to the fourth year, decreasing thereafter to reach a figure at the twelfth year of 88 in the female and 94 in the male. Tables I-A and I-B show the averages of the chest width-hip width index in both boys and girls at each age.

A special study is being made of those children who had a higher index than the average for their age and those who had a lower index than the average for their age. Present findings indicate that girls who menstruate earlier than 12 1/2 years have an index below the average, and that those girls who menstruate later than this age have, in the majority of cases, an index greater than the average.