What device is used to measure blood pressure?

The device used to measure blood pressure is a sphygmomanometer. It uses an inflatable cuff to temporarily compress an artery and a gauge or electronic sensor to determine the pressure in the bloodstream.

Traditional manual sphygmomanometers use an inflatable arm cuff, a rubber bulb, and either a mercury column or an aneroid dial. With the auscultatory method, a clinician also uses a stethoscope to listen for Korotkoff sounds as cuff pressure is released. The first sounds indicate systolic pressure, while the disappearance of the sounds indicates diastolic pressure.

Samuel Siegfried Karl Ritter von Basch invented an early sphygmomanometer in 1881. Scipione Riva-Rocci introduced a more practical cuff-based design in 1896, and Nikolai Korotkov added the listening technique for determining diastolic pressure in 1905. Modern digital monitors usually estimate pressure by detecting oscillations in the artery rather than using a stethoscope.

A stethoscope may be used alongside a manual sphygmomanometer, but it does not measure blood pressure by itself. An otoscope examines the ear, and a thermometer measures temperature. Blood pressure readings are reported as systolic over diastolic pressure, in millimetres of mercury, or mmHg.