Analysis of Stresses around the Orbit Due to Masseter and Temporalis Muscles Respectively

Abstract

A series of experiment was made for the purpose of clarifying the respective influence in the distribution of stress and internal force, which are produced by the masseter and temporalis muscles in the upper facial skeleton at the action of biting. The experiments were to measure the strains in the macerated skull under static loading. The analyses of stress and internal force were made from the strains measured in the fronto-nasal, fronto-zygomatic, supraorbital and infraorbital regions. They were approximately decomposed according to the force of each muscle. In general, the action of the masseter muscle has a tendency to strengthen the tensile stress, whereas the action of the temporalis has a tendency to strengthen the compressive stress. Basing on the results obtained, some commentaries were done on the functional interpretations in the morphological studies of various authors dealing with the facial skeleton.