Strain of carpal ligaments during wrist-joint motion

To obtain a more accurate apprehension of the mechanics of the wrist-joint, the kinematical behaviour of the carpals and the length changes of the ligaments during hand-motions are determined. These structures are represented by radio-opaque markers. Using X-ray photogrammetric principles the 3D coordinates of those markers are calculated at some fifty positions of a movement-cycle. Clear differences are observed between these 3D, experimentally obtained data and prevailing concepts on ligament behaviour based on 2D kinematics of the carpal bones. It is suggested, based on results, that during some motions the carpal joint is not stabilized by one of the tested ligaments. [Edited author abstract; In English]