Syncope, VasovagalSyncopeSupine PositionGravity SensingOtolithic MembraneRotationGravitationPelvisDizzinessVestibule, LabyrinthOrthostatic IntoleranceOrientationWeightlessness SimulationHeart RateHeadHead MovementsPelvic BonesPostural Orthostatic Tachycardia SyndromeAutonomic Nervous SystemBlood PressurePatient PositioningSpinal CurvaturesSemicircular CanalsFigural AftereffectPeripheral Nervous System AgentsOptical IllusionsAccelerationTorsion AbnormalityBaroreflexVestibular DiseasesLordosisWeightlessness CountermeasuresGravity, AlteredValsalva ManeuverLipid BilayersEye MovementsVestibular Function TestsClomipramineHypogravityTrochlear Nerve DiseasesPatellofemoral JointKinesthesisEtilefrineNitroglycerinSpace FlightAutonomic Nervous System DiseasesBradycardiaSympathetic Nervous SystemIllusionsHypergravityMidodrineProprioceptionElectron Microscope TomographyRadius FracturesAdaptation, PhysiologicalHemodynamicsFluid ShiftsVision, BinocularMotion SicknessPsychophysicsSpace PerceptionRange of Motion, ArticularOculomotor MusclesCarotid SinusPatellaElectrocardiographyDepth PerceptionVascular ResistanceBone MalalignmentLower Body Negative PressureSpineNeck MusclesAdministration, SublingualCardiac OutputNystagmus, PhysiologicVolar PlateIschiumOcular Motility DisordersAcetabulumShy-Drager SyndromeBlood Flow VelocityDimyristoylphosphatidylcholinePatellar DislocationModels, MolecularSacrumUltrasonography, Doppler, TranscranialSupinationBiomechanical PhenomenaLenses, IntraocularProtein Structure, SecondaryVagus NerveCardiovascular DeconditioningLegTime FactorsMassageRegional Blood FlowAstronautsMotion PerceptionSurgical EquipmentLens Subluxation