6 nternal and external rotation of the shoulder : Effects of lane , end - range determination , and scapular motion

c s t e a a r b m a he purpose of this study was to determine whether lane, end-range determination, or scapular motion ffects shoulder range-of-motion measurements. In 16 ealthy subjects, instrumentation with a magnetic trackng device was used to measure shoulder internal and xternal range of motion. The arm was supported hile it was rotated either actively or passively with a easured torque. There was a significant main effect f plane for internal rotation (P .001) but not for xternal rotation (P .584). Passive humerothoracic otion was significantly greater than active humerohoracic motion for internal rotation (P .006) and xternal rotation (P .01). Active and passive huerothoracic motion was significantly greater than ctive and passive glenohumeral motion in 6 of the active conditions and all 7 passive conditions P .002). Our results suggest that significant mounts of scapulothoracic motion may impact meaurements of isolated glenohumeral joint motion. J Shoulder Elbow Surg 2005;14:602-610.)