Fig. 2.

Lumbar spine X-ray, lateral view. The intervertebral height (A) is calculated by dividing the sum of anterior, middle, and posterior intervertebral disc heights by 3 (a+b+c/3). The angle between the superior and inferior endplates is the degree of segmental lordosis (B) at the site of surgery and total lordosis (C) is measured according to the Cobb method in which the angle appearing in each segment is based on the L1 superior endplate and the S1 superior endplate for lumbar lordosis.