Lumbar lateral radiograph exhibits examples of L5–S1 vertebral body slippage, disc height, and vertebral body height measurement. Line segment a indicates the superior endplate of S1. Line segment b indicates vertebral body slippage length at L5–S1. Line segment c marked the distance between the midpoint of the inferior endplate of L4 and the superior endplate of L5, which indicates L4–5 disc height. Line segment d marked the distance between the midpoint of the superior endplate of L4 and the inferior endplate of L4, which indicates L4 vertebral body height.