Bird beak sign (sigmoid colon)

Last revised by Mohamed Saber on 16 Mar 2022

Bird's beak sign of the sigmoid is one of the signs of sigmoid volvulus. It represents gradual narrowing/tapering of the sigmoid colon up to the level of obstruction during contrast/barium insertion to the rectum or on CT.

When located in the sigmoid colon, it suggests the diagnosis of sigmoid volvulus. If the obstruction is complete, no contrast will pass beyond the level of the obstruction but if the obstruction is incomplete some contrast can pass into the proximal twisted sigmoid colon.


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

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Cases and figures

  • Case 1: pseudo-obstruction - degenerative leiomyopathy
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  • Case 1
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  • Case 2
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