Plural Fluid Studies: Which Ones Should We Order?

In general, when I'm thinking about ultrasound in the lung or the pleural space, I try to start and end with structures that I recognize. The pleural fluid is going to be dark or anechoic and in free flowing effusions will be just above the diaphragm. You'll often see the tip of the lung floating around with respiration. So that's also called the sinusoid sign.