Forty‐five Northern Irish families: A cephalometric radiographic study

Abstract The individual bones that are identifiable from lateral skull radiographs have been analysed for the parents and growing children of 45 families. There were at least four children in each family and altogether there were 95 sons and 102 daughters. The youngest child was not less than seven years of age. Traced outlines were made of the bones and 24 linear and angular measurements were made; the raw data were transformed into scores to overcome differences due to age and sex. Analyses of variance of within and between families showed that for all the variables, the scores for persons in different families were significantly less similar, (P < 0.001), than scores to be found within families. Correlations were then computed for each variable between the mothers and fathers, the mothers and sons, the mothers and daughters, the fathers and sons, the fathers and daughters, brothers and sisters, paired brothers and paired sisters. It was found that there were no statistically significant correlations between the mothers and fathers, but for all the other combinations that were examined there were many correlations significant at a 0.1% and 1.0% level.