SpasmMyofascial Pain SyndromesMuscle Relaxants, CentralMusculoskeletal DiseasesMusculoskeletal SystemMuscle SpasticityMusclesNeck MusclesNeuromuscular Nondepolarizing AgentsSpasms, InfantileVecuronium BromideNeuromuscular Blocking AgentsNeuromuscular AgentsPancuroniumMuscle, SmoothCervical AtlasOccipital BoneAtracuriumMusculoskeletal PainMuscle, SkeletalMuscle ContractionMuscle ProteinsSuccinylcholineMuscle RelaxationMuscle, Smooth, VascularElectromyographySpinal Cord InjuriesAndrostanolsMuscle Fibers, SkeletalTolperisoneHemifacial SpasmBotulinum Toxins, Type AMotor NeuronsMuscle DevelopmentCarisoprodolNeuromuscular Depolarizing AgentsTubocurarineMephenesinDantroleneMuscle RigidityMuscle FatigueCoronary VasospasmMuscle Fibers, Fast-TwitchMuscle Denervation