Electromyographic studies of mandibular muscles in basic jaw movements

Abstract

The muscular activity for various jaw movements has been measured and the total electrical activity of the different muscles compared on a time basis. Based on observed electrical activity and anatomic considerations, it has been concluded that the external pterygoid and suprahyoid muscles were primarily responsible for the uncontrolled opening movement. The masseter and temporal muscles, of those listed, were responsible for the closing movement. The internal pterygoid muscles were not tested. The left external pterygoid muscle was mainly responsible for the movement of the mandible to the right and the right external pterygoid muscle for the opposite movement. Both external pterygoid muscles were responsible for the protrusion of the mandible. The analysis and discussion of the material covering the different sets of dentures will be presented at a later time.