Inverted Napoleon hat sign

Case contributed by Matt A. Morgan


Chronic low back pain

Patient Data

Age: 20 years
Gender: Female

These radiographs show the "inverted Napoleon hat sign" on the frontal view, indicative of bilateral L5 pars defects and spondylolisthesis.


CT correlate of the radiographic images

Case Discussion

The "inverted Napoleon hat sign" is a finding on lumbar spine radiographs that indicates bilateral L5 pars defects with anterolisthesis of L5 over S1.

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