The measurement of the blood pressure monitor manufacturers of human beings is usually
accomplished by applying a variable pressure through a pressure cuff to the brachial artery in the upper arm of the test subject. As the pressure is varied, the sound of the bloodflow through the artery or the pressure pulses generated by the artery are usually measured and used as indications of various blood pressure values. These two techniques, known as the ausculatory and oscillometric methods, respectively, can both beautomated.
With an automated ausculatory blood pressure monitor manufacturers, a pump inflates the cuff such that the brachial artery, is occluded. Then the pressure is reduced in increments by the monitor and an audio transducer or microphone located on the arm of thesubject adjacent the distal portion of the occluded artery converts the sound produced when blood flow is reestablished into electrical signals. These sound signals, known as "Korotkoff" or "K-sounds", are first detected when the cuff pressure is at alevel known as the "systolic" pressure. The monitor continues to reduce the cuff pressure until these K-sounds disappear. The cuff pressure level where this occurs is known as the "diastolic" pressure. Once the systolic and diastolic pressures havebeen determined, the monitor deflates the cuff to zero pressure.