Sub-acromion impingement syndrome: Scapular morphometric analysis: A study on dry bones among Eastern Indian population

Introduction: Among various factors responsible for the development of chronic shoulder pain worldwide, the role of scapula, as a bony factor, is very important. This study focuses on evaluating the scapular shape and contour as a determinant of sub-acromion impingement syndrome. This was a cross-sectional observational study conducted on dry bones. Material and Methods: Dry scapulae (42 right sided and 38 left sided) were studied by taking digital photographs in different views and analyzing various parameters (critical shoulder angle (CSA), glenoid inclination, shape of acromion process, etc.) using ImageJ analyzer. Results were analyzed using measures of central tendency, and statistical significance was analyzed by measuring P values with the help of SPSS software (v25). Results: There were 40% Type I, 38.75% Type II, and 21.25% Type III scapulae, respectively. The Type I and III scapulae showed significant variations on the basis of various acromion overhangs (anterior overhang was 9.03 mm and 11.08 mm in Types I and III, respectively, while for the lateral overhang, the values were 9.73 mm and 6.25 mm in Types I and III, respectively) and angles (lateral acromion angle was 79.5° and 71.9° for Types I and III, respectively, whereas the coraco-acromion angle was 37° and 30.8° in Types I and III, respectively). The glenoid inclination and CSA were also significantly variable between all three types of scapulae. Discussion and Conclusion: The scapular morphology plays a pivotal role which can be extrapolated on a radiological basis in pertinent patients to determine the chances of developing pathological shoulders in future.