Fig. 3.

An example of the vertical axis and sagittal plane of a vertebral body. The vertical axis (arrow) was defined as the line containing the center of gravity (G) and parallel to the line connecting anterior edges of the vertebral foramen on the upper and lower vertebral end plates (a, b). The sagittal plane (c) contained the center of gravity and anterior edges of the vertebral foramen on the upper and lower end plates