Dictionary.net

A s. elicited by auscultatory percussion, said to indicate pleuritic effusion. "The patient is seated, and is auscultated in the dorsal region." An assistant places a sou on the thorax in different parts according to directions, and percusses. The ear of the auscultator listens at the opposed corresponding parts. The healthy side is first examined; then the side with pleurisy, where the note is much higher. A clear metallic sound indicates pleuritic effusion; when this sound is absent there is no effusion.