What clinical finding is indicative of a pleural rub?

The identification of a pleural rub is best indicated by the presence of distinct sounds occurring during both inspiration and expiration. This sound is generated when inflamed visceral and parietal pleurae rub against each other, often due to conditions such as pleuritis. During auscultation, a pleural rub has a scratchy or creaking quality, and the characteristic presence of these sounds during both phases of the respiratory cycle is critical for identifying this finding.

The fact that it can be heard during both inspiration and expiration helps clinicians distinguish it from other respiratory sounds, thereby providing a clear indication of an underlying pleural condition. The audible nature of pleural rubs means that they typically require a stethoscope to be assessed adequately, though in some cases they may be audible without instrumentation if the condition is severe enough.