The configuration of the laminas and facet joints in degenerative spondylolisthesis: a clinicoradiologic study

The configuratory variation of laminas and facet joints was discussed with reference to development of degenerative spondylolisthesis and its clinical symptoms. The authors have classified the configuration of laminas in the lower lumbar spine into three different types, (W1, W2, and N), based on the two characteristic features of the lamina: 1) whether or not the inferior articular processes are wider than the waist part of the lamina, and 2) whether or not the facet joint spaces can be recognized on plain anteroposterior (AP) radiographs