52 Year old woman with low back pain. MRI shows degenerated L5/S1 disc with radial annular tear.
Degenerative disc changes are associated with the development of annular tears (it does not necessarily indicate a traumatic cause, as the word tear implies). Annular tears (or fissures) involve either part or the entire thickness of the annulus. They run perpendicular to the long axis of the annulus and occur more commonly in the posterior half of the discs, usually at L4-5 and L5-S1. The radial annular tear is considered by many to be responsible for pain.
MRI shows focal areas of high signal on T2WI or on contrast enhanced T1WI. On T2 sagittal images, radial tears appear as globular or horizontal lines of high signal within posterior annulus.
1. Kaplan et al. Muskuloskeletal MRI: Spine. W.B. Saunders Company 2001.
2. Munter et al. Serial MR Imaging of annular tears in lumbar intervertebral discs. Am J Neuroradiol 2002;23:1105-1109.