Relationship between clavicle length and scapular resting alignment in healthy subject

• Published in: British journal of sports medicine Vol. 45; no. 4; p. 377
• Main Authors: Toda, H, Yamamoto, K, Yoshida, M, Katayose, M
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine 01.04.2011; BMJ Publishing Group LTD; BMJ Publishing Group
• Subjects: Athletes; Correlation analysis; Kinematics; Ligaments; Pathology; Shoulder; Sports injuries; Sports medicine
• ISSN: 0306-3674; 1473-0480
• DOI: 10.1136/bjsm.2011.084038.188

Background The scapular resting alignment is one of typical quantitative clinical evaluation of the scapular kinematics. The scapular alignment could be affected by the feature of clavicle morphology, but not studied by previous study. Objective To investigate the correlation between clavicle length and three-dimensional scapular resting alignment. Design Descriptive study. Setting Laboratory setting. Participants 60 shoulders of 30 males without a history of shoulder pathology. Independent variables The clavicle length was normalised by body height (CL/height) and by biacromial arc (CL/biacromial). Two of these normalisation data were used for analysis. Main outcome measurements Three-dimensional scapular resting alignment was measured with 3D motion-capture system. The scapular resting alignment was described by scapular orientation and position relative to the trunk. To describe scapular orientation and position, three of scapular rotation and two clavicular movements were used. Three scapular rotations were external/internal rotation, upward/downward rotation, and posterior/anterior tilt. Two clavicular movements were protraction/retraction and elevation/depression. The correlations of two normalisation data of clavicle length with three scapular rotations and two clavicular movements were calculated by the Pearson's correlation coefficient, with a statistical significance level of p less than 0.05. Results Significant linear correlations were found between the CL/height and posterior tilting (r=0.34, p=0.008), between CL/biacromial and elevation (r=0.31, p=0.018), retraction (r=0.55, p<0.001), upward rotation (r=0.39, p=0.002), posterior tilting (r=0.28, p=0.033) and internal rotation (r=-0.59, p<0.001). Conclusion Our results demonstrated that the normative clavicle length with biacromial arc is more related to the scapular resting alignment than the normative clavicle length with body height.