Fig. 5
From: Lung ultrasound—a primary survey of the acutely dyspneic patient
Curtain sign. a Chest X-ray illustrates the extent (dotted line) to which the lower parts of the lung (open arrow) cover the abdomen. b LUS shows the pleural line (solid arrow) ends abruptly with an edge (thin arrow) forming an acoustic shadow, the “curtain sign,” which slides over the liver (L) with respiration. The lateral diaphragm is always hidden by the curtain and not seen in normal LUS. c An example of an abnormal curtain sign: a small effusion (E) causing an incomplete “curtain” sign (thin arrow) and exposing the lateral diaphragm (dotted arrow)