Silhouette Signs
October 21st, 2019
Overview
Look For
- Obliteration of normally clear outlines between the lung fields and adjacent structures such as the heart, aorta or hemidiaphragm.
Significance
- Loss of normal borders appears when the adjacent area of lung is consolidated or collapsed.
Interpretation
- Upper right heart border / ascending aorta - anterior right upper lobe
- Upper left heart border - anterior left upper lobe
- Aortic knob / arch - apical left upper lobe
- Right heart border - right middle lobe
- Left heart border - lingular lobe
- Anterior hemidiaphragms - lung bases / lower lobes
Examples
- Obscuration of the right hemidiaphragm suggesting right lower lobe consolidation
![Obscuration of the right hemidiaphragm suggesting right lower lobe consolidation]()
- Obscuration of the left hemidiaphragm suggesting right lower lobe consolidation
![Obscuration of the left hemidiaphragm suggesting right lower lobe consolidation]()
- Obscuration of the ascending aorta, suggesting right upper lobe consolidation
![Obscuration of the ascending aorta, suggesting right upper lobe consolidation]()
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