This paper brings together the research findings on biparietal diameter from more than 50 investigations. It constitutes a synthesis of present knowledge pertaining to the head breadth of physically normal, North American infants and children.
There are sections on the following topics: methodologic considerations, means for head width, variability in head width, findings from longitudinal data, and the relation of head width to other variables. Included in the section on variability is a table of norms and comments on its clinical use.
Representative generalizations are:
1. The average North American white child attains 30% of adult head width by the middle of prenatal life, 60% by birth, 80% by 6 postnatal months, 90% by 3 years and 95% by 9 years.
2. Throughout the period from birth to 12 years, the 2 sexes differ systematically: head width distributions for North American white girls have slightly lower means and smaller standard deviations than comparable distributions for boys.
3. At 1 year of age, the limits of normal variation in head width are 11.4 cm. and 14.8 cm. for North American white boys, 11.1 cm. and 14.3 cm. for North American white girls. The normal limits at age 10 years are 12.9 cm. and 16.3 cm. for boys, 12.7 cm. and 15.9 cm. for girls.
4. North American Negro school children have narrower heads than North American white school children, and North American Japanese school children wider heads than North American white school children. The mean biparietal diameter of children of Mexican descent approximates that of American Negro children.
5. The association between width of head and length of head is low—of the order r = .25. A similarly low relationship exists between width of head and width of hips, but the relationship between width of head and width of face is appreciably higher.
Analysis of Anterior Trunk Symmetry Index (ATSI) in healthy school children based on 2D digital photography: normal limits for age 7-10 years