Fig. 2. Schematic of seven virtual segments of C-spine for evaluation of epicenter and number of involved segments of herniated disc materials.

Two imaginary lines (*) are drawn by tracing inner margin of bilateral pedicles, and additional four lines that divide inter-pedicular space evenly are drawn. Additionally, another two lines that divide same space at lateral aspect of lines drawn along inner margin of pedicles are drawn. As result, eight virtual lines are drawn on posterior aspect of body of cervical spine, and seven segments are created.