What instrument is used to measure blood pressure?

A sphygmomanometer is the instrument specifically designed to measure blood pressure. It typically consists of an inflatable cuff that is wrapped around the patient's arm and a gauge that measures the pressure within the cuff. The device works by occluding blood flow in the brachial artery as the cuff is inflated and then gradually released, allowing the practitioner to identify the systolic and diastolic pressures based on Korotkoff sounds or by observing the gauge.

In contrast, a thermometer measures body temperature, a pulse oximeter is used to assess oxygen saturation in the blood, and an electrocardiogram records the heart's electrical activity. Each of these tools serves distinct purposes in medical evaluation, making the sphygmomanometer the only appropriate choice for blood pressure measurement.