Measurement of the Shoulder Motion Using 3-D Motion Capture Technique / 대한정형외과연구학회지

PURPOSE: Measurement of scapular motion as a component of shoulder motion is clinically limited. The purpose of this study was to measure the scapulothoracic motion and glenohumeral motion separately using the 3-D motion capture technique. MATERIALS AND METHODS: Twelve healthy adult male volunteers (Mean age: 28 years) without any history of shoulder pathologies were included for the study. Shoulder motions in 3 planes -forward flexion, abduction in scapular plane and abduction in coronal plane- were measured in 3-dimensions. And we estimated skin slippage of optical markers according to the flexion of the shoulder using ultrasonography. RESULTS: During forward flexion, abduction in scapular plane and abduction on coronal plane, scapula showed upward rotation, external rotation and posterior tilting. Especially, during abduction on coronal or scapula plane, scapula was upwardly rotated and posteriorly tilted in linear fashion. The scapulo-humeral rhythm was 6.7:1 in whole range of abduction on the coronal and scapular plane. Estimated skin slippage of the marker on the inferior angle of scapula was 4.3+/-1.7 cm and bigger than those of other markers. CONCLUSION: This study failed to get a useful data of shoulder motion due to marker position which did not reflect scapula motion actually. But this trial could be a help for the future study, as this study suggested the possibilities of 3-D motion capture technique for the measurement of shoulder motion.

Scapular Dyskinesis

PURPOSE: Scapular dyskinesis is an alteration in the normal position or motion of the scapula during coupled scapulohumeral movements. Vast majority of shoulder pathologies are known to be related with scapular motion abnormalities. Because there being enthusiasm about scapular pathology in recent literatures, understanding scapular dyskinesis seems to be an important subject. The authors describe the importance of scapular abnormality in terms of shoulder pathology. MATERIALS AND METHODS: Usually the inhibition or disorganization of activation patterns in scapular stabilizing muscles lead to scapular dyskinesis. This motion abnormality has more important values in Elite Athletes because it might be the sign of future shoulder pathology; for example, SLAP and internal impingement. Treatment of scapular dyskinesis is directed at managing underlying causes and restoring normal scapular muscle activation patterns by kinetic chain-based rehabilitation protocols. Treatment is also important to prevent secondary shoulder injuries. RESULTS AND CONCLUSION: Understanding scapular pathology may be the main key to approach to the shoulder pathology. Also treating scapular pathology might be important in preventing secondary shoulder injuries.