[[isthmic spondylolisthesis]] AKA [[spondylolysis]]: a failure of the neural arch as a result of a
defect in the [[pars interarticularis]] (identifiable as a discontinuity in the neck of the “[[Scotty dog]]”
on oblique LS-spine x-ray). May be seen in 5–20% of spine x-rays
((Frymoyer JW. Back Pain and Sciatica. N Engl J Med.
1988; 318:291–300)).
Rarely produces central [[spinal canal stenosis]] since only the anterior part of the vertebral body shifts forward. May cause narrowing of the [[neural foramen]].