Volume 89 (1981) Issue 4 Pages 457-478
Skeletal maturation was analyzed in 1072 radiographs of the right hand and wrist in 458 pairs of identical twins and 78 pairs of fraternal twins, aged 12 to 18 years. Because skeletal maturity is already completed in the older children, the age groups of 12-14 years in boys and 12 years in girls were mainly discussed. Skeletal maturity was assessed by the K score, TW1 and TW2 methods, and heritability was evaluated by intrapair correlation, percent deviation and revised percent deviation, heritability indices, F-ratio and genotypic-environmental ratios. As regards estimation of heritability, all the skeletal scores and ages assessed by various methods showed high significant correlations with one another, and skeletal maturation suggested a high heritability which is almost the same in both sexes.