Beak sign (arterial dissection)

The beak sign of arterial dissection is the acute angle formed at the edge of the false lumen in aortic dissection in axial cross-section. It is formed by the borders of the outer aortic wall and the intimal flap, and may be partially thrombosed (blunted beak). It is a reliable characteristic that helps in distinguishing from the true lumen.

The acute "beak" angulation represents the transverse limit of the dissection, where false lumen propagation is occurring along with a tear in the media.


The term bird's beak sign is used in a number of other contexts: see bird beak sign (disambiguation)

Inspired signs

Article information

rID: 8928
System: Vascular
Section: Signs
Tag: cases, cases
Synonyms or Alternate Spellings:

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Cases and figures

  • Figure 1: annotated image
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