Facial MusclesFacial ParalysisFacial NerveSmilingFacial ExpressionBotulinum Toxins, Type AZygomaNerve TransferFacial AsymmetryNeuromuscular AgentsMasticatory MusclesSkull Base NeoplasmsMusclesTorticollisElectromyographyParotid NeoplasmsBlepharospasmMuscle ProteinsMuscle, SmoothMuscle, SkeletalMuscle Fibers, SkeletalMuscle, Smooth, VascularHemifacial SpasmFacial Nerve DiseasesFacial BonesSialorrheaMuscle DevelopmentFacial InjuriesMuscle Contraction