Fig. 2

Registration of 3D shoulder models to motion analysis data. a Image-based 3D shoulder models with scapular and humeral bones, articular cartilage, and custom markers were aligned with the marker positions from the motion tracking data. b The relative positions between the centers of the humeral head and glenoid cavity were calculated with six degrees of freedom motions (an example of the rotational motion between the Y axis of the humeral head and glenoid cavity)