Retrocardiac sail sign

Last revised by Daniel J Bell on 21 Apr 2021

The retrocardiac sail sign represents the characteristic and highly specific appearance of left lower lobe collapse on a frontal chest x-ray.

Radiographic appearance

The collapsed, medially displaced left lower lobe is represented by a triangular area of increased density with sharp margins, superimposed on the heart shadow which resembles the unfurled sail of a yacht.  The heart contours remain preserved (no silhouette sign), while the contour of the left hemidiaphragm is at least partially effaced 1.

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.