DEFORMATION OF CRANIAL SUTURES DURING MASTICATORY ACTIVITY: A STRAIN GAUGE APPLICATION

This study was designed to identify a relationship between the activity of the masticatory muscles and the resultant movement in two morphologically dissimilar patent cranial sutures. Strain gauges were implanted along the saggital and across the squamosal-parietal sutures using the Macaca nemestrina as an experimental model. This monkey model was chosen because the morphology of the sutures under investigation and their anatomical relationship to the muscles of mastication resemble those observed in man. Parameters of resultant strain were recorded at these sutures during stimulation of selected masticatory muscles and during chewing. A two-way analysis of variance was used to compare the differences in strain between the squamosal-parietal and sagittal sutures. A Student-Newman-Keuls Test was used to identify differences in strain at the squamosal-parietal suture as a result of the independent contraction of the six muscles tested. The direction and magnitude of the strain across the beveled squamosa-parietal suture was found to be markedly different in direction and greater in magnitude from that strain recorded across the butt-ended sagittal suture. The potential capability of the squamosal-parietal suture to absorb stress during mastication and its anatomical proximity to the temporomandibular joint suggest a functional relationship between this patent suture and the temporomandibular joint. The beveled configuration of the squamosal-parietal suture and the demonstrated capability of this suture to undergo tension and compression during mastication suggest that this suture may act as a shock absorber during mastication