Silhouette sign of Felson: right middle lobe pneumonia
A young woman is sent with a diagnosis of pneumonia.
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Consolidation of the anterior segment of the RUL and the middle lobe of the right lung. Moderate volume loss of the middle lobe.
Demonstration of Ben Felson's Silhouette sign.
On the PA view, the anterior segment consolidation is seen superior to the minor fissure of the right lung.
The silhouette sign is noteworthy because it is described when something "disappears" rather than when it "appears", as is usual in the rest of medicine
- 1. Puddy E, Hill C. Interpretation of the chest radiograph. Continuing Education in Anaesthesia, Critical Care & Pain. 2007;7(3):71-75.
- 2. Felson B, Felson H. Localization of intrathoracic lesions by means of the postero-anterior roentgenogram; the silhouette sign. Radiology 1950;55:363-374