title: The measurement of three dimensional scapulohumeral kinematics--a study of reliability.
abstract: OBJECTIVE
  To validate a system, using electromagnetic movement sensors, for the simultaneous measurement of scapular and humeral positions.
  
  
  METHODS
  The study was designed to analyse the repeatability and to quantify the inherent measurement errors, using two observers to measure the movements of five normal subjects.
  
  
  BACKGROUND
  Following an earlier study of a system to measure three dimensional scapula motion, the method has been developed to incorporate simultaneous measurement of humeral and scapular position using a new design of scapula locator and a two-channel measurement system.
  
  
  METHODS
  The system was used to measure the scapula movements accompanying abduction of the shoulder. The scapula locator was applied at 10 degrees intervals of abduction. This was measured initially using a fluid filled goniometer, but, in a second part of the study, using an additional motion sensor.
  
  
  RESULTS
  In the single channel study, the 95% confidence intervals were less than 4 degrees and 10 mm. When simultaneous measurement of arm position was performed the confidence intervals were little changed.
  
  
  CONCLUSIONS
  A new system for the measurement of scapulohumeral relationships has been shown to have good inter-and intraobserver reliability. This study opens the way for a full investigation of the scapula motion accompanying three dimensional shoulder motion in both normal subjects and in patients having shoulder pathology.
authors.affiliation: Department of Mechanical, Materials and Manufacturing Engineering, University of Newcastle Upon Tyne, UK.
authors.forename: N D
authors.initials: ND
authors.lastname: Barnett
authors.forename: R D
authors.initials: RD
authors.lastname: Duncan
authors.forename: G R
authors.initials: GR
authors.lastname: Johnson
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D055590:Electromagnetic Phenomena; D006801:Humans; D006811:Humerus / Q000502:physiology*; D010173:Palpation; D016059:Range of Motion, Articular / Q000502:physiology; D015203:Reproducibility of Results; D012540:Scapula / Q000502:physiology*; D012785:Shoulder Joint / Q000502:physiology*