Abstract
The skull forms the basic structure against many competing functional demands. The skull is also related with masticatory organs, and the outlines of the nasal cavity, the orbit, and the paranasal sinuses make the ideal pillars against masticatory pressure. That is, the conductive routes of masticatory pressure are the canine pillar, the zygomatic pillar, and the pterygoid pillar. To examine the arrangement of bone lamellae of the compact bone and matrix fibril bundles of the pillar of the skull operated particularly by composite stress with mastication. I observed bone lamellae and matrix fubril bundles of maxilla with all teeth removed from a man's body for anatomical laboratory with a scanning electron microscope.
At the maxillary body on the canine pillar, the Haversian system arranged in sagittal and matrix fibril bundles on the surface were arranged in a suprero-inward direction. At the frontal process of maxilla, the Haversian system arranged in sagittal and matrix fibril bundles on the surface were arranged upward. At the glabella on which right and left canine pillars joined, the Haversian system were arranged inward to outward, and the matrix fibril bundles were arranged suprero-outward. At the frontal process of zygomatic bone on the zygomatic pillar, the Haversian system was arranged in a sagittal direction, and a comparatively big bone marrow space existed at the center. Matrix fibril bundles ran suprero-outward at the surface of the zygomatic process of maxilla and outward-superior at the zygomatic bone. The Haversian system and matrix fibril bundles of zygomatic arch on the horizontal branch of the zygomatic pillar were arranged antero-posterior. At the pterygoid process on which masticatory pressure of the last molar was conducted, the Haversian system was arranged upward to downward and the matrix fibril bundles on the surface of the outside of lateral lamina were arranged suprero-outward. In short, arrangement of the Haversian system and matrix fibril bundles on each pillar agreed with the conductive direction of masticatory pressure.
The pillar of the skull was the conductive route of masticatory pressure and joined with fibrous suture. The joining region of the pillar was composed of a saw-shaped suture of a curved suture line. The suture joined the adjacent bone with fibrous connective tissues, and connective tissues of the suture were transferred to a fibrous layer of outer periosteum. The frontal process of maxilla on the canine pillar joined the pars squamosa of frontal bone with the frontal-maxillary, and the triangular frontal sinus was divided into right and left, existing inside the pars squamosa of the frontal bone.
