An Electromyographic Analysis of Masticatory Muscle Imbalance with Relation to Skeletal Growth in Dogs

¹ The Murry and Leonie Guggenheim Foundation Institute for Dental Research, New York University, College of Dentistry

By the use of a telemetering system for recording the electromyogram, the functional activity of the teniporid muscle in dogs has been analyzed under normal conditions as well as under conditions of muscle imbalance. In the controls, the action of the temporal muscle was on a unilateral basis when the food material was confined to either sidle of the mouth, respectively. Under most conditions of surgically created muscle imblablance the unilateral action of the tempimrl muscle w ts superseded by a bilateral type of activity. When both masseter muscles were removed, thus preserving a condition of anatomical symmetry, the action of the temporal muscle remained on a unilateral basis. The effects of the various muscle imbalances on the growth and development of the cranio-facial skeleton were for the most part slight and localized to areas directly associated with the muscles that were removed. More general changes in morphology occurred only when both masseters and one temporal muscle were removed.