Growth allometry of the human face: analysis of the osseous component of the mid and lower face in Brazilian fetuses.

Growth of facial bones was studied in 30 human fetuses ranging from 14 to 35 weeks of gestation (both sexes together), investigating both bivariate and multivariate allometry with principal components analysis (PCA). Weight of the mandible, maxillae, zygomatic, palatine, vomer and both lateral masses of the ethmoid bones was measured and correlated with fetal weight. The relative order of growth rates was similar for bivariate and multivariate results. These results indicate that the growth rate of the lower face is greater than growth rates of the vomer and palatine bones, and is less than growth rates of the maxillae, zygomatic and ethmoid bones. Bivariate and multivariate results present only one significant difference: the mandible grows with positive allometry in bivariate study and with negative allometry in multivariate analysis. The analysis performed in this study provides an approximation of the biological phenomenon of growth which may be useful in the interpretation of facial growth.