title: A marker-based measurement procedure for unconstrained wrist and elbow motions.
abstract: A protocol is proposed to obtain the joint angles of wrist and elbow from tracked triads of surface markers on each limb segment. Cuffs placed on the limb support the rigidity of the triads. Additional markers are used to mark the approximate positions of joints. Corrections of surface marker data for skin motion are derived from a priori knowledge about plausible joint motions. In addition, ill-conditioned states are trapped when the elbow is nearly fully extended. The protocol is applied to sample motions which demonstrate the use and the effect of the corrections. The results show that the model assumptions are reasonable and that accurate joint rotations can be obtained. The correction steps prove to be an essential part of upper-extremity movement analysis.
authors.affiliation: Helmholtz-Institute for Biomedical Engineering at Aachen University of Technology, Germany. rschmidt@hia.rwth-aachen.de
authors.forename: R
authors.initials: R
authors.lastname: Schmidt
authors.forename: C
authors.initials: C
authors.lastname: Disselhorst-Klug
authors.forename: J
authors.initials: J
authors.lastname: Silny
authors.forename: G
authors.initials: G
authors.lastname: Rau
mesh_terms: D000328:Adult; D000465:Algorithms; D001132:Arm / Q000502:physiology; D016477:Artifacts; D004551:Elbow Joint / Q000502:physiology*; D004867:Equipment Design; D005260:Female; D005542:Forearm / Q000502:physiology; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D011403:Pronation / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D012785:Shoulder Joint / Q000502:physiology; D012867:Skin; D013484:Supination / Q000502:physiology; D014955:Wrist Joint / Q000502:physiology*