Flat floor of fourth ventricle sign

Andrew Murphy and A.Prof Frank Gaillard et al.

The flat floor of fourth ventricle sign is useful in detecting a pontine mass and is a sign of mass effect. The normal floor of the fourth ventricle (remember that the floor is anterior) normally slopes upwards towards the midline, with the facial colliculi visible on either side. 

It is a non-specific sign of a pontine mass, or process with mass effect but in children is most frequently seen in brainstem gliomas.

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Article information

rID: 5738
Section: Signs
Synonyms or Alternate Spellings:

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Cases and figures

  • Figure 1: normal fourth ventricle
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  • Figure 2: flat Floor
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