CT of adult lumbar disc herniations mimicking posterior apophyseal ring fractures.

This report concerns 35 adult patients with lumbar or sciatic pain and axial CT findings reportedly associated with posterior apophyseal ring fractures. Review of the CT images suggested two pathophysiologic categories. (1) Posterior Schmorl--A posterior intravertebral disc herniation with posterior displacement of a fractured or remodelled vertebral margin. (2) Calcified subligamentous--Reactive annular and or posterior longitudinal ligament calcification at the periphery of a herniated disc with or without remodelling and anterior displacement of the posterior vertebral margin.