Douglas A. Bourne, Anthony M.T. Choo, William D. Regan, Donna L. MacIntyre and Thomas R. Oxland
The goal of this study was to measure 3-dimensional shoulder motion by use of a direct invasive technique during 4 different arm movements in healthy volunteers. Eight subjects with healthy shoulders were recruited. Optoelectronic marker carriers were mounted on bone pins, which were inserted into the lateral scapular spine. Subjects performed 4 different arm movements while the motion was being recorded by a precision optoelectronic camera. During abduction, the scapula tipped posteriorly (44Â° Â± 11Â°), rotated upward (49Â° Â± 7Â°), and rotated externally (27Â° Â± 11Â°). For reaching, the scapula consistently rotated upward (17Â° Â± 3Â°) and rotated internally (18Â° Â± 6Â°) whereas tipping was generally less than 10Â° (5Â° Â± 2Â°). Overall, the range of scapular movement for the hand behind the back was small and variable, with most rotations not exceeding 15Â°. For horizontal adduction, the scapula tipped anteriorly (8Â° Â± 3Â°), rotated upward (5Â° Â± 2Â°), and rotated internally (27Â° Â± 6Â°). The authors conclude that these scapular rotations provide normative data that will be useful for diagnosing scapular dysfunction.
Journal of Shoulder and Elbow Surgery, Volume 16, Issue 2,