Inverted Napoleon hat sign
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was changed:
The inverted Napoleon hat sign isseen on the frontal radiograph of the spine at the level of the fifthlumbar vertebra and the sacrum. Bone overlying the sacrum simulates thedome of an inverted Napoleon hat, with the transverse process formingthe hat's tapered brim.
This sign is produced when a severely subluxed L5vertebral body projects end on and overlaps the sacrum, with thesuperimposition of images appearing as an inverted Napoleon hat. Thissign is apparent in the severe high grade spondylolisthesis and / orsevere lumbar lordosis.
- occurs with markedanterolisthesis of L5 on S1
- visible on a frontalradiograph of lumbar spine
- implies the presenceof bilateral spondylolysis and significant spondylolisthesis
- Spondylolysisresulting in this degree of spondylolisthesis is more often congenitaland/or traumatic in origin and less often degenerative
- the "brim" ofhat is formed by the downward rotation of the transverse processes
- "dome" ofhat is body of L5
- the sign can also beseen with marked exaggeration of the normal lordosis at the lumbosacraljunction
-<p>The <strong>inverted Napoleon hat sign</strong> is-seen on the frontal radiograph of the spine at the level of the fifth-lumbar vertebra and the sacrum. Bone overlying the sacrum simulates the-dome of an inverted Napoleon hat, with the transverse process forming-the hat's tapered brim. </p><p>This sign is produced when a severely subluxed L5-vertebral body projects end on and overlaps the sacrum, with the-superimposition of images appearing as an inverted Napoleon hat. This-sign is apparent in the severe high grade <a href="/articles/spondylolisthesis-1">spondylolisthesis </a>and / or-severe lumbar lordosis.</p><ul>-<li>occurs with marked- anterolisthesis of L5 on S1</li>- <li>visible on a frontal- radiograph of lumbar spine</li>- <li>implies the presence- of bilateral <a href="/articles/spondylolysis" title="spondylolysis ">spondylolysis </a>and significant spondylolisthesis</li>- <ul>-<li>Spondylolysis- resulting in this degree of spondylolisthesis is more often congenital- and/or traumatic in origin and less often degenerative</li>- </ul>-<li>the "brim" of- hat is formed by the downward rotation of the transverse processes</li>- <ul>-<li>"dome" of- hat is body of L5</li>- </ul>-<li>the sign can also be- seen with marked exaggeration of the normal lordosis at the lumbosacral- junction</li>- +<p>The <strong>inverted Napoleon hat sign</strong> is seen on the frontal radiograph of the spine at the level of the fifth lumbar vertebra and the sacrum. Bone overlying the sacrum simulates the dome of an inverted Napoleon hat, with the transverse process forming the hat's tapered brim.</p><p>This sign is produced when a severely subluxed L5 vertebral body projects end on and overlaps the sacrum, with the superimposition of images appearing as an inverted Napoleon hat. This sign is apparent in the severe high grade <a href="/articles/spondylolisthesis-1">spondylolisthesis </a>and / or severe lumbar lordosis.</p><ul>
- +<li>occurs with marked anterolisthesis of L5 on S1</li>
- +<li>visible on a frontal radiograph of lumbar spine</li>
- +<li>implies the presence of bilateral <a href="/articles/spondylolysis">spondylolysis </a>and significant spondylolisthesis<ul><li>Spondylolysis resulting in this degree of spondylolisthesis is more often congenital and/or traumatic in origin and less often degenerative</li></ul>
- +</li>
- +<li>the "brim" of hat is formed by the downward rotation of the transverse processes<ul><li>"dome" of hat is body of L5</li></ul>
- +</li>
- +<li>the sign can also be seen with marked exaggeration of the normal lordosis at the lumbosacral junction</li>
References changed:
- 1. Talangbayan LE. The inverted Napoleon's hat sign. Radiology. 2007;243 (2): 603-4. <a href="http://dx.doi.org/10.1148/radiol.2432030499">doi:10.1148/radiol.2432030499</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/17456883">Pubmed citation</a><span class="auto"></span>
Systems changed:
- Spine