Coracoid index was measured as the perpendicular distance from the coracoid tip to the line drawn tangential to the glenoid rim on the axial image. The first line is the tangential line to the glenoid rim. The second line is the line starting from the coracoid tip and running perpendicular to the first line. The distance between the coracoid tip and the intersection point of the first and second lines is the coracoid index.