Figure 1.

Annular protrusion grading (white arrows) and visibility scoring of the nucleus pulposus; A, Annulus protrusion grade 1, equal to dorsal aspect of vertebral body and visible nucleus pulposus (white asterisk); B, annulus protrusion grade 2, minimal dorsal bulging with respect to vertebral body and gas in the central part of the discus (white arrowhead); C, annulus protrusion grade 3, with moderate dorsal bulging without reaching the spinal cord, (black #); D, severe dorsal bulging of disc material with contact and deformation of the spinal cord