Figure 2

Stenosis site and inflection point. A. Type A lesion: lesion in which the distal end of the stenosis (arrow) is located proximal to the inflection point (arrowhead) at a distance ≥0.5 of a vertebral body based on the posterior height of the 3rd vertebral body (double arrow). B. Type B lesion: lesion in which the distal end (arrow) of the stenosis is located proximal to the inflection point (arrowhead) at a distance <0.5 of a vertebral body or located distal to the inflection point.