Measurements and forms of intervertebral foramina of the posterior lumbar spine

: The authors carried out measurements of 168 intervertebral foramina on the level L4 to L5 and L5 to S1 as well as the thickness of the spinal nerve, and examined their form. They certified that the measurements of the intervertebral foramen L5 to S1 are really statistically lower as the measurements of the intervertebral foramen L4 to L5 at relatively the same average thickness of the spinal nerve.