Cranial morphology and facial type: Is it appropriate to describe the face using skull terminology?

Abstract

BackgroundTerminology that comes from the anthropometric index, which is indicative of the form of the skullcap, is widely used to describe the face in orthodontics. Using this terminology assumes that the face and skull always follow the same pattern of morphology. The aim of this study was to test the hypothesis that the morphology of the face corresponds with the morphology of the skull. MethodsMeasures related to the cranial and facial indexes were taken randomly from 51 dry human skulls with neutral occlusion, selected from a larger collection. Skulls were classified, according to the cranial index, as dolichocephalic (<76.0), mesocephalic (76.0–<81.0), or brachycephalic (≥81.0) and according to the facial index as leptoprosopic (≥90.0), mesoprosopic (85.0–<90.0), or euryprosopic (<85.0). The McNemar-Bowker test and linear regression models were used to assess the relationship between the cranial and facial morphologies. ResultsThe correspondence values between the cephalic and facial index ratings in expected cephalofacial pairs (brachycephalic and euryprosopic, mesocephalic and mesoprosopic, and dolichocephalic and leptoprosopic) were observed to be only 3.9%, 7.8%, and 13.7%, respectively. Coefficients of linear regression confirmed a weak influence of facial measurements on the morphology of the skull. ConclusionsFacial morphology exerts little influence on skull shape and, therefore, does not support the widespread use of a terminology derived from the cranial index. The development of a standardized diagnostic terminology is timely given the increasing use of electronic records in health research and facilitating data sharing across different areas.