Fundamental Radiological Findings: Silhouette Sign (Right Hemidiaphragm)

OVERVIEW

This page is dedicated to covering the important radiological finding of a silhouette sign at the right hemidiaphragm

WHAT IS IT?

A silhouette sign refers to the loss of a border between two structures radiologically: In the case of a silhouette sign at the right hemidiaphragm the clear sharp margin between the right hemidiaphragm and the right lung field is obscured. This is typically a finding appreciated on a chest X-ray. 

DIFFERENTIAL DIAGNOSIS FOR THIS FINDING

When seeing a silhouette sign at the right hemidiaphragm, it is important to keep in mind the following possible causes of this finding:

  • Right lower lobe pneumonia  
  • Right lower lobe atelectasis
KEY FEATURES TO LOOK FOR WHEN CHARACTERIZING THE FINDING

When seeing a silhouette sign at the right hemidiaphragm, there are a few important radiological features one should look at to try and characterize the finding. These features can help navigate the differential diagnosis above.

 

Page Updated: 03.01.2017