Location

Spine

Diagnosis

Spondylolysis

Discussion

CT of the spine with discontinuity of the lateral bodies of the vertebrae and the posterior elements at the same level. This simple sign of discontinuity has been labeled the incomplete ring sign and is specific for fracture of the pars interartcularis (spondylolysis) as seen on CT scans. This sign is usually readily apparent because on no scan will the entire cortical ring be identified. Other causes, such as spina bifida occulta, can also appear as an incomplete ring, but with the discontinuity at a different site, thereby making differentiation easy.

Reference

Langston JW, Gavant ML: “Incomplete ring” sign: a simple method for CT detection of spondylolysis. J Comput Assist Tomogr 1985 Jul-Aug;9(4):728-9.

Figures

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Attachments:


spineparsdefctag2.jpg (image/jpeg)


spineparsdefctag1.jpg (image/jpeg)