1999 Volume 19 Issue 2 Pages 176-190
To study the dynamic arrangement of matrix fibrils of the compact bone and the bone trabeculae of the spongy bone of the attaching region of the masticatory muscles on the mandible and the stress against the tensile by the masticatory muscles to the mandible, we examined with a scanning electron microscope mainly the arrangement of matrix fibrils of the compact bone of the mandible with all teeth dissected from male anatomy cadavers.
The superficial bone matrix of the external basic lamellae attached by the masticatory muscles was formed by collagen fibril bundles. Matrix fibril bundles were arranged suitably for the stress of the tensile with the masticatory muscles. At Tuberositas masseterica and Tuberositas pterygoidea, matrix fibril bundles ran from under-anterior to over-posterior. Matrix fibril bundles ran downward at the central region of the coronoid process. At the pterygoid fovea, matrix fibril bundles ran from under-anterior to over-posterior.
The external basic lamellae of the attaching region of the masticatory muscles were composed of bone lamella about 3μum thick, which ran in the same direction as the superficial matrix fibrils, and the bone lamella about 1μm thick, which crossed diagonally to the adjacent lamella. In the osteons of the Haversian lamellae, the lamellae about 5μm thick, which ran in the same direction as the superficial matrix fibrils, and the lamellae about 1μm thick, which ran concentrically, were arranged alternately. The bone trabeculae had the dynamic arrangement suitable for the tensile of the masticatory muscles. The bone trabeculae of the angle of the mandible were arranged from under-anterior to over-posterior. The bone trabeculae of the pterygoid fovea were arranged from front-inferior to back-posterior.
