Frimann-Dahl sign

Last revised by Joshua Yap on 25 Jan 2023

The Frimann-Dahl sign is a diagnostic sign demonstrated when three dense lines, representing the sigmoid walls, are seen converging to the site of obstruction in sigmoid volvulus and associated with empty rectal gas 1.

History and etymology

Johan Frimann-Dahl (1902-1982) was a Norwegian Professor of Radiology and Head of the Roentgen Department from 1937-1972, at Ullevål Hospital, Oslo, Norway 2.

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Cases and figures

  • Case 1
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  • Case 2
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