Prenatal development of the human limb bones (humerus, ulna, radius, femur, tibia, fibula) was studied. Cross-sectional data, consisting of 21 anthropometric measures of these bones were collected from 122 Japanese fetuses between the gestational ages of 18 and 40 weeks. Principal component analysis was applied to the data to provide multivariate assessments of morphological patterning among the variables. Three orthogonal components that accounted for 94.2% of the overall sample variation were

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... extracted. The first component accounted for 88.2% of the variation and represented an axis of overall body size that was dependent on gestational age. The second and third components both reflected a trend in shape involving the cartilaginous parts of the humerus and femur. The findings indicated that different growth factors existed between the ossified and cartilaginous parts of fetal long bones. Multivariate allometric coefficients were extracted from the first principal component. The variables that were related to the construction of the articulate showed positive allometry, and the central widths of the diaphysis showed negative allometry compared with total size. In prenatal skeleton, certain shape changes are functionally linked to and required by changes in body size. A comparison among the coefficients of long bone length revealed that lower limb bones grew faster than upper limb bones during the period under study here. Allometric coefficients were equivalent among bones within a limb, whereas homologous bones in the upper and lower limb grew at different rates. fetus; long bone; multivariate allometry The available evidence on the ontogeny of human limb bones reveals distinct patterns of prenatal growth. Several studies have previously considered the relationships between measurements and the degree of ossification of long bones in human fetal limbs, as well as their correlation to the Crown-Rump length (CRlength). In these studies, different techniques have been employed, such as direct measurement of long bones (Keleman et al. 1984) , measurement after cleaning and