A longitudinal and cross-sectional analysis of the growth of the postnatal cranial base angle.

Radiographs of 32 children, 16 girls and 16 boys, taken at 1 month, 3 months, 9 months, and once a year until 5 years 9 months were selected from the Denver Series. The cranial base deflection was measured by five sets of angles. A cross-sectional evaluation revealed a significant decrease in angle size by all methods of measurement by 9 months of age. Little change was noted after 1 year, 9 months, indicating that studies beginning after 2 years would not find this decrease. All individuals followed a pattern of reduction between 1 month and 9 months with variable changes at 3 months. Choice of landmark affected the degree and timing of the observed change but not the overall pattern. Differences in measuring techniques evaluated the mean degree of deflection to range from -6.9 degrees to -13.8 degrees.