Fig. 5
Schematic diagram of L1 vertebral body anterior wedge deformity of sagittal plane. Y axis and Z axis are the human coordinate system. a: Load a (solid red line with arrow) perpendicular to the upper edge of L1 was applied to the upper edge of L1 with a force of 700 N. b: Load b (solid yellow line with arrow) perpendicular to the lower edge of L1 was applied to the upper edge of L1 with a force of 700 N. The angle between the upper edge of L1 and Y axis was defined as angle α. The angle between the lower edge of L1 and Y axis was defined as angle β. L1: 1st lumbar vertebral body