Skeletal development of non‐institutionalized children with low intelligence quotients

Children of both sexes with mild mental retardation show delays in skeletal maturation and cortical bone growth, but boys in general are more affected than girls. Skeletal age for both sexes is below normal in the younger age groups, but approaches normality at adolescence. None of the measures of IQ is significantly correlated with any of the regional measures of skeletal age in the hand‐wrist. The approach toward normality of skeletal development in this population at adolescence is reflected in their normal time of first appearance of the adductor sesamoid. Anomalies of the hand‐wrist reflect irregularities in comparing normal and low‐IQ children. Only brachymesophalangy V displays significantly higher frequencies in the low‐IQ groups. Due to the cross‐sectional nature of the study and the different methods of classifying anomalies, little can be said about the other comparisons. Growth in cortical bone reflects a consistent trend for both the humerus and second metacarpal. While measures of total diameter and total cross‐sectional area do appear to be below normal standards, the measures of the marrow do not. This finding accounts for a decreased cortical bone thickness and cross‐sectional area in the low‐IQ sample. All measures of the humerus correlate significantly with two IQ scores in the boys and all three scores in the girls. Measures of the total metacarpal and marrow area show significant correlations with the three IQ scores among low‐IQ boys, while only measures of total metacarpal area show significant correlations with verbal IQ in low‐IQ girls. The degree of mental deficiency, then, is only irregularly associated with deficits of bone size for age

Audiology · Bone age · Cognition · Developmental psychology · Humerus · Intelligence quotient · Mental development · Normality · Population · Psychiatry · Wrist · Anatomy · Birth, Development, and Health · Internal Medicine · Medicine · Psychology · Sexual Differentiation and Disorders

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