Radiological determination of cranial size and index by measurement of skull diameters in a population of children in Brazil* Determinação radiológica do índice e do tamanho craniano por mensuração dos diâmetros cranianos em uma população infantil brasileira

OBJECTIVE: To measure radiologically obtained skull diameters and, based on these data, calculating the cranial index and size to compare with diameter measurements and indices reported in the literature, particularly those reported by Haas. MATERIALS AND METHODS: The present study evaluated 732 individuals with no cranial disease, whose skull diameters were measured, Subsequently, the authors calculated the cranial index and size which demonstrate the different phases of the skull growth by inner-table to inner-table measurements. RESULTS: The comparative study of diameters averages by inner-table measurements has demonstrated a clearly progressive skull growth in the first year of life for both genders, and a slower growth as from the second year. Overall diameters averages did not present any significant difference between male and female individuals. CONCLUSION: Cranial index and size are good skull growth indicators, especially in the first four years of life, a period characterized by an accelerated growth in the first year and a moderate growth until the fourth year. After this age, a slight and stable growth occurs with a decrease in the statistical value. No statistically significant difference was found for both genders. It is recommended that mean diameters are utilized for both genders; and it is suggested that the cranial index is utilized until four years of age, and the cranial size after the age of four, as the ideal parameter for following up the skull growth.