Radiographic measurements. A. Coronal balance; a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph. B. Sagittal balance: a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph. (anterior; positive, posterior; negative). C. Clavicle angle: the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle (left side up; positive, left side down; negative). D. T1 tilt angle; the angulation of the upper endplate of T1 to the horizontal line (left side up; positive, left side down; negative).