Figure 3.

Spinal Top View of a pathological spine with indication of the graphic elements used for the Cartesian reference System. The graphic representation is of the top-back of the examined subject, so that right and front of the graphic correspond to the real right and front. The middle of the Cartesian axes is represented by the line joining C7-S1, i.e. the vertical axis oy that becomes a point in the horizontal xoz plane constituting the Top View. The ordinate (ox) is the latero-lateral (LL) normal spinal axis that has been defined as the line passing through S1 (o) and parallel to the anterior-superior iliac spines. The abscissa (oz) is the antero-posterior (AP) normal spinal axis, that is the line orthogonal (at 90°) to the previous one passing through S1 (o): this line corresponds to the AP body and pelvis axes, as well as to that of the spine in the theoretical normal model of Figure 2.