Hawaiian craniofacial morphometrics: average Mokapuan skull, artificial cranial deformation, and the "rocker" mandible.

Craniofacial morphology and cultural cranial deformation were analyzed by the computer morphometric system in 79 adult Hawaiian skulls from Mokapu, Oahu. The average Hawaiian male was large, but similar in shape to the female. Both were larger than the present Caucasian, showed a greater dental protrusion, and possessed a larger ANB angle, flatter cranial base, and larger facial heights. Correlations in Hawaiian craniofacial structure were found between an increasing mandibular plane angle and 1) shorter posterior facial height, 2) larger gonial angle, 3) larger cranial base angle, and 4) smaller SNA and SNB angles. Of the 79 skulls studied, 8.9% were found to have severe head molding or intentional cranial deformation. Significant statistical differences between the molded group and the nonmolded group are, in decreasing significance: 1) larger upper face height, 2) smaller glabella to occiput distance, and 3) increased lower face height with deformation. The morphometric differences were readily seen by graphic comparison between groups. It is postulated that external forces to the neurocranium result in redirection of the growth vectors in the neurocranial functional matrix, including the cranial base, and secondarily, to the orofacial functional matrix. There is a possibility that the cranial deformation is a retention of the normal birth molding changes. The Polynesian "rocker jaw" was found in 81% to 95% of this populace. This mandibular form occurs only with attainment of adult stature and craniofacial form. This data agrees with the hypothesis that mandibular form is modified by the physical forces present and their direction in the orofacial functional matrix.