What is the name of the instrument used to measure blood pressure?

The instrument used to measure blood pressure is called a sphygmomanometer.

The word combines Greek sphygmos, meaning “pulse,” with manometer, a device for measuring pressure. A traditional sphygmomanometer uses an inflatable cuff wrapped around the upper arm and a mercury column or aneroid dial to display pressure. Modern automated versions use electronic sensors and show the reading digitally.

Blood pressure is usually reported as two numbers in millimetres of mercury, or mmHg. The systolic number records pressure when the heart contracts; the diastolic number records pressure while the heart relaxes between beats. In a manual measurement, a stethoscope can be used to hear Korotkoff sounds as cuff pressure is released.

The stethoscope is therefore commonly used alongside a manual sphygmomanometer, but it is not the measuring instrument itself. An otoscope examines the ear, while a thermometer measures temperature. Early blood-pressure devices evolved during the nineteenth century, and Russian physician Nikolai Korotkov’s 1905 work made it possible to identify both systolic and diastolic pressure by sound.