Zygapophysial joint pain in selected patients

Figure 4 Sagittal section through the neuroforamina of a severely degenerated lower lumbar spine of a 70-year-old man. The z-joints are in a subluxated position due to the loss of segmental height. The pars interarticularis of L5 is being eroded superiorly by the inferior articular process of L4 and inferiorly by the superior articular process of S1 (*). Such pars erosion is a prerequisite for the development of degenerative spondylolisthesis. There is no cartilage in the L5/S1 z-joint (arrow heads). Z-joints: Zygapophysial joints.