步态分析课件（英文）

Joint FunctionJoint Function & & GAIT AnalysisGAIT Analysis JointsJoints ¾¾ A joint occurs when boneA joint occurs when bone--end meets end meets bonebone--endend ¾¾ Synovial jointSynovial joint zz Bone ends covered with Bone ends covered with cartilagecartilage zz Relative large range of Relative large range of motionmotion zz Surrounded by a capsule filled with Surrounded by a capsule filled with synovial synovial fluidfluid Knee Joint MotionKnee Joint Motion Hip Joint MotionHip Joint Motion Joint FunctionJoint Function The ability of a joint to maintain The ability of a joint to maintain an appropriate functional position an appropriate functional position throughout an intended range of motionthroughout an intended range of motion A stable joint is able to carry required loads A stable joint is able to carry required loads throughout normal ranges of motionthroughout normal ranges of motion Types of movementsTypes of movements Types of movements (contTypes of movements (cont’’d)d) Joint Reaction ForcesJoint Reaction Forces These forces produced via:These forces produced via: Compression of two articular surfacesCompression of two articular surfaces Compressive ForcesCompressive Forces Joint Contact ForcesJoint Contact Forces GAITGAIT ¾¾ Utilizes minimal energy to move COMUtilizes minimal energy to move COM ¾¾Walking is a highlyWalking is a highly--coordinated process coordinated process involvinginvolving zz CNSCNS •• BrainBrain •• Spinal cord Spinal cord •• Peripheral nervesPeripheral nerves zz MSSMSS •• MusclesMuscles •• Bones & JointsBones & Joints Single GAIT cycleSingle GAIT cycle The major events:The major events: ¾¾ Stance PhaseStance Phase zz Heel StrikeHeel Strike zz Foot FlatFoot Flat zz Toe OffToe Off ¾¾ Swing PhaseSwing Phase zz AccelerationAcceleration zz Deceleration Deceleration Stance PhaseStance Phase Swing phaseSwing phase Single GAIT cycleSingle GAIT cycle Support during GAIT cycleSupport during GAIT cycle Ground reaction forceGround reaction force Biomechanics of GAIT AnalysisBiomechanics of GAIT Analysis ¾¾ Important variables Important variables zz TimeTime zz MassMass zz ForceForce zz Centre of gravityCentre of gravity zz MomentsMoments zz MotionMotion •• LinearLinear •• AngularAngular Determinants of GAITDeterminants of GAIT ¾¾ Pelvic rotationPelvic rotation ¾¾ Pelvic obliquityPelvic obliquity ¾¾ Knee flexion in stance phaseKnee flexion in stance phase ¾¾ Ankle mechanismAnkle mechanism ¾¾ Foot mechanismFoot mechanism ¾¾ Lateral displacement of bodyLateral displacement of body GAIT AnalysisGAIT Analysis ¾¾ Systemic study of human walkingSystemic study of human walking •• Using Using experiencedexperienced observersobservers •• Augmented by Augmented by instrumentationinstrumentation •• Measuring body movementsMeasuring body movements •• Body mechanicsBody mechanics •• Activity of the musclesActivity of the muscles ¾¾ PurposePurpose ¾¾ Aid in treatmentAid in treatment ¾¾ Helps to improve understandingHelps to improve understanding Methods of GAIT AnalysisMethods of GAIT Analysis Few of the methods used :Few of the methods used : ¾¾ Visual gait analysisVisual gait analysis ¾¾ Timing the gait cycleTiming the gait cycle ¾¾ Direct motion measurement systemsDirect motion measurement systems ¾¾ ElectrogoniometersElectrogoniometers ¾¾ ElectromyographyElectromyography ¾¾ Combined Kinetic / Kinematic systemsCombined Kinetic / Kinematic systems Abnormal GAIT PatternsAbnormal GAIT Patterns ¾¾ Anterior trunk bendingAnterior trunk bending ¾¾ Posterior trunk bendingPosterior trunk bending ¾¾ Lateral trunk bendingLateral trunk bending ¾¾ Increased lumbar lordosisIncreased lumbar lordosis ¾¾ CircumductionCircumduction ¾¾ SteppageSteppage The EndThe End Pelvic rotationPelvic rotation Pelvic obliquityPelvic obliquity Knee flexion in stance phase,Knee flexion in stance phase, Ankle mechanism, Foot mechanismAnkle mechanism, Foot mechanism Lateral displacement of bodyLateral displacement of body Anterior trunk bendingAnterior trunk bending Posterior trunk bendingPosterior trunk bending Increased lumbar lordosisIncreased lumbar lordosis CircumductionCircumduction SteppageSteppage Visual gait analysisVisual gait analysis ¾¾ Depends on the skill of observerDepends on the skill of observer ¾¾ Subject should be observed from different Subject should be observed from different sides to observe gait abnormalitiessides to observe gait abnormalities ¾¾Minimum length to be walked = ~10Minimum length to be walked = ~10--12 m12 m ¾¾ Compare range of motion at joints during Compare range of motion at joints during walking with those observed on walking with those observed on examination plinthexamination plinth ¾¾ Cameras may be used Cameras may be used Timing the gait cycleTiming the gait cycle ¾¾ Two typesTwo types zz FootswitchesFootswitches •• One switch beneath heel, other beneath forefootOne switch beneath heel, other beneath forefoot •• Connected to computer with trailing wire/ transmitterConnected to computer with trailing wire/ transmitter •• Measure timing of stance phaseMeasure timing of stance phase zz Instrumented walkwaysInstrumented walkways •• Covered with electrically conductive substanceCovered with electrically conductive substance •• Electrical contacts on subjectElectrical contacts on subject’’s shoess shoes •• Interrupt beams of 2 photoelectric cells to find speedInterrupt beams of 2 photoelectric cells to find speed •• Also measures position of foot contact Also measures position of foot contact Direct motion measurement Direct motion measurement systemssystems ¾¾ Found generally in research labsFound generally in research labs ¾¾ Light string attached to back of beltLight string attached to back of belt ¾¾While walking string is pulled through an While walking string is pulled through an instrument instrument zz Uses tacho generator or optical encoder Uses tacho generator or optical encoder zz Measures its speedMeasures its speed ¾¾ Two strings used Two strings used zz Measure lateral displacementMeasure lateral displacement ElectrogoniometersElectrogoniometers ¾¾Makes continuous measurements of the Makes continuous measurements of the angle of a jointangle of a joint ¾¾ Potentiometer devicesPotentiometer devices zz Variable resistorVariable resistor zz Turning of central spindleTurning of central spindle •• Change in electrical resistance Change in electrical resistance zz Measures joint angleMeasures joint angle •• Body is connected to one limbBody is connected to one limb •• Spindle is connected to the connecting limbSpindle is connected to the connecting limb TriaxialTriaxial goniometersgoniometers on Hip, knee on Hip, knee and ankleand ankle ElectromyographyElectromyography ¾¾Measures electrical activity of contracting Measures electrical activity of contracting musclemuscle ¾¾Main methods Main methods zz Surface electrodesSurface electrodes zz FineFine--wire electrodeswire electrodes zz Needle electrodesNeedle electrodes ¾¾ Helps in timing muscle activation Helps in timing muscle activation ¾¾ But cannot measure strength of But cannot measure strength of contraction contraction Combined Kinetic / Kinematic systemsCombined Kinetic / Kinematic systems Combined Kinetic / Kinematic systemsCombined Kinetic / Kinematic systems ¾¾ Measurements in 2D or 3DMeasurements in 2D or 3D ¾¾ MeasuresMeasures zz DisplacementsDisplacements zz VelocitiesVelocities zz AccelerationsAccelerations zz Position and orientation of body segmentsPosition and orientation of body segments zz Angles of jointsAngles of joints ¾¾ Measure positions of markers at 50 Hz (20ms intervals)Measure positions of markers at 50 Hz (20ms intervals) ¾¾ Uses many of the previous mentioned measurement Uses many of the previous mentioned measurement systemssystems zz ElectrogoniometersElectrogoniometers zz Visual methods like videosVisual methods like videos zz Force platforms , etcForce platforms , etc Joint Function& GAIT Analysis Joints Knee Joint Motion Hip Joint Motion Joint Function Types of movements Types of movements (cont’d) Joint Reaction Forces Compressive Forces Joint Contact Forces GAIT Single GAIT cycle Stance Phase Swing phase Single GAIT cycle Support during GAIT cycle Ground reaction force Biomechanics of GAIT Analysis Determinants of GAIT GAIT Analysis Methods of GAIT Analysis Abnormal GAIT Patterns The End Pelvic rotation Pelvic obliquity Knee flexion in stance phase,Ankle mechanism, Foot mechanism Lateral displacement of body Anterior trunk bending Posterior trunk bending Increased lumbar lordosis Circumduction Steppage Visual gait analysis Timing the gait cycle Direct motion measurement systems Electrogoniometers Triaxial goniometers on Hip, knee and ankle Electromyography Combined Kinetic / Kinematic systems þÿ Combined Kinetic / Kinematic systems