Lumbosacral and Spinopelvic Anatomy and Pathology - Isthmic Spondylosis of L5

Isthmic spondylolysis of L5 in a 29–year–old woman who died from aspiration of a nose–bleeding. She had no history of back pain. At L5 the pedieles are broad and wide and project posterolaterally. This spondylolysis defect resembles a hypertrophic elephant–foot type pseudarthrosis, bordered medially by a capsule or membrane that contributes to the trifoliate configuration of the spinal canal. The L5 roots are recessed in a furrows immediately anterior to the defect. The facet joints are severely altered by osteoarthrosis changes and the lamina is markedly thickened on the right side, rendering the spinal canal slightly asymmetric. The epidural space is occupied by fat that is interspersed with sparse epidural veins. Anteriorly the L4 nerves and some arteries snugly swerve around the base of the transverse processes.