A MIXED LONGITUDINAL STUDY ON SKELETAL MATURATION IN HEALTHY FINNISH CHILDREN AGED 5 TO 10 YEARS

In a mixed longitudinal "Model Child "study in Finland the bonespecific rating system of Tanner et al. was employed for the assessment of skeletal age from hand-wrist X-rays. The present study comprised the ages from 5 to 10 years. The skeletal age of 33 boys and 51 girls was determined at each birthday up to chronological age 10. A total of 505 assessments were made. Three observers rated each X-ray. About 25%, of values differed by one stage and only 0.1% by two stages. The largest number of differences occurred in the rating of the navicular. The mean and ranges of the overall scores and of the corresponding skeletal ages with standard deviations are presented for boys and girls in each group. Both boys and girls from 8 years onwards had an upward trend of about 0.6 year above the standards. The question whether the standards possibly are somewhat too low for Finnish children in these age groups calls for further study with a larger series. The annual increments of the overall score and of the long and round bone scores are presented. The increments for girls had the spurt shown by the standards between ages 9 and 10. Both the round bone and the long bone increments had a wide dispersion. A positive correlation was found between the midparent height and the child's skeletal age. This correlation was statistically almost significant in 6-and 7-year-old girls. The mother's height was also positively correlated, but the father's height appeared not to be related to the child's skeletal maturation. The differences between the correlation coefficients were, however, not statistically significant.