Figure 1.

Procedure for creating homologous models. A: Template and 41 landmarks. B: Setting the coordinate system. Origin: at the most posterior point sequential with the largest anteroposterior diameter on the undersurface of the vertebral body. Z: Line with the largest anteroposterior diameter on the undersurface of the vertebral body. Y: Vertical line perpendicular to the Z-axis passing through the origin. X: Horizontal line perpendicular to the Z- and Y-axis passing through the origin. C: Landmark placement on each three-dimensional bone model. D: Homologous model of image C.