A three dimensional study of fetal craniofacial growth and development in the pigtailed macaque (Macaca nemestrina) using 3D-CT reconstruction techniques and finite element scaling

Growth and development of the fetal craniofacial complex in Macaca nemestrina has been primarily documented in two dimensions using roentgenographic cephalometrics techniques. When growth and development is modeled in two dimensions, a general and incomplete model of a three dimensional process is produced. Additionally, variation within the third dimension is lost. Finally, size correlated shape changes are difficult to isolate. This research will construct a three dimensional model of growth and development of the fetal craniofacial complex in M. nemestrina. This model will then be used to document growth and allometry in three dimensions.

A three dimensional model was created from 17 male pigtailed macaques ranging from 137 to 157 gestational days. Three dimensional landmark data were collected from 3D-CT reconstructed images using VoxBlast for Windows 3.1 (VayTek, 1994). Thirty-seven cranial landmarks were utilized. A three dimensional model of the fetal craniofacial complex was produced using FIESCA, a finite element scaling program (Morris, 1991). FIESCA was also used to model deformations local to each landmark.

These results illustrated that three dimensional analyses greatly augment previous two dimensional studies. Previous studies of fetal craniofacial growth produced models that describe growth relative to a central registration point. This research produced a model that describes growth relative to the biological form itself.

Finite element scaling also permits the evaluation of morphological changes within functional units. Allometry was observed in the fetal craniofacial complex. The dentofacial palate displayed the greatest degree of size changes. Regions within the neurocranium displayed the greatest degree of shape changes. The mandible, upper and lower face displayed lesser degrees of size and shape changes.

This work was supported by NIH grants DE02918, RR00166, HD08633, HD10356, HL19187, NSF grant 9601027, grant from Chatham College, the Mark Diamond Research Foundation at SUNY Buffalo, and Sigma Xi Foundation.