On a PA chest radiograph of a patient with right-sided pleural effusion, the upper border of the opacity is highest in the axilla and concave medially. Which term describes this radiographic contour?

• A Hampton hump
• B Air crescent sign
• C Silhouette sign
• D Meniscus sign ✓

Explanation

A free pleural effusion produces a concave upper border with the highest point laterally in the axilla, known as the meniscus sign, because fluid tracks along the pleural surfaces under gravity. The Hampton hump refers to a wedge-shaped pleural-based opacity in pulmonary infarction. The air crescent sign is seen in aspergilloma or cavitating masses. The silhouette sign describes loss of a normally visible border when a structure of similar density is directly adjacent.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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