[Measurements of anterior fontanels in Chinese]

Assessment of the size of the anterior fontanel is used as an index of cranial development from birth to the second year of life. From January to May, 1988, measurements of anterior fontanel size were collected for all available newborns and infants from the nursery and well-baby clinics. The size of anterior fontanel was measured as the average value of the length (anterior-posterior dimension) and the width (transverse dimension), as proposed by Popich in 1972. Any fontanel too small to be measured was judged to be closed. Totally 704 subjects, divided into 10 groups by age (3 days, 1, 2, 4, 6, 9, 12, 15, 18, and 24 months) were measured. Results showed that the mean size of anterior fontanel in these 10 groups was 26.7 mm, 25.8 mm, 24.9 mm, 25.7 mm, 20.2 mm, 14.9 mm, 11.5 mm, 10.2 mm, 13.0 mm, and 12.1 mm, respectively. Results also showed a variation of fontanel size in all groups. There was a tendency toward decrease in fontanel size after six months of age. There were no significant differences in size and age of closure of the anterior fontanel between two sexes. Closure of the fontanel was first noted in about 5% of the babies 6 months after term, but in about 8% of the babies at 24 months of age, the fontanel had not closed. The median age of fontanel closure was 14.5 months in males and 14.3 months in females.