In Vivo Kinematics Of The Midcarpal Joits

[Objective]To investigate the method of the research of relative movement of among carpus iv invo and to identify decide the movement of the median wrist during articulation carpi flecting/extending/radial deviating/rule deviating.[Methods]Elected healthy 10 volunteers,wrist joints were CT scanned,carpus were three-dimensional reconstructed in surgery operation simulation system which was developed by Dr lijing.Centroidal and moment of inertia of scaphoid and lunatum were calculated in this system,reference coordinate system was founded in the capitate anthropogenicly,to employ finite screw axis express the rotation and translation of the scaphoid and lunatum relative the capitate.[Results]During wrist joint been mostly ulnar deviated,the scaphoid extended 19.2±10.3relative capitate,supinatioed 6.9±5.2°,radial deviated 19.3±6.2°,lunatum extended 27.8±12.6°,supinatioed 8.9±4.9°,radial deviated 14.0±4.8°,47%of the rotation in the midcarpal jolts;During wrist joint been mostly radial deviated,the scaphoid flection was 12.9±6.4°,pronation was 9.2±4.8°,ulnar deviation was 15.0±3.8°,lunatum flection was 10.5±3.9°,pronation was 7.5±4.8°,ulnar deviation was 15.3±3.9°,76%of the rotation in the midcarpal joits;During wrist joint been mostly flected,the scaphoid extended 32.6±5.2°relative the capitate,suinatioed 0.3±2.6°,radial deviated 0.8±3.6°,lunatum extended 41.5±6.9°,pronated 0.6±2.0°, ulnar deviated 1.8±1.5°,65%of the rotation in the midcarpal joits;During wrist joint been mostly extended,scaphoid flected 7.9±3.9°relative the capitate,supinatio 1.4±2.4°,ulnar deviated 6.0±5.1°,lunatum flected 20.7±5.0°,supinatioed 2.7±2.9°,,ulnar deviated 5.3±3.4°,34%of the rotation in the midcarpal joits.During wrist joint been extending the translation of the scaphoid and lunate relative capitate was larger than other position.Scaphoid translated 1.3±0.6mm to palmaris relative to capitate,lunatum translated 1.5±0.5mm to palmaris.[Conclusion]The motor direction of the scaphoid and lunatum relative to the capitate is coincident,but rotation of the lunate more than the scaphoid.During wrists ulna/radial deviating,there are out-of-plane motion rotation of the scaphoid and lunate relative to capitate except radial/ulna deviation;During radial deviation rotation mainly occurs in the midcarpal joist,during ulnar deviation rotation of the midcarpal joist and the radial joist is equate roughly.During wrist flexing/extending motion of the scaphoid and lunatum relative to capitate mainly is extention/flexion,out-of-plane motion is little.During wrist flexing motion mainly occurs in the midcarpal joist, During wrist extending motion mainly occurs in the radiocarpal joist,during extending translation of the scaphoid and lunatum relative to capitate than other potion.