What is a Sphygmomanometer?

Sometimes you feel weakness and you consult the doctor, the doctor uses a special cuff to measure your blood pressure and suggests to have a cold coffee when your bp is high and a hot coffee when it is low. Now, what is that instrument used by the doctor, that is nothing but the sphygmomanometer.

On This Page, we will Learn About the Following:

  • Sphygmomanometer

  • Sphygmomanometer parts

  • Sphygmomanometer diagram

  • Bp apparatus parts, types of the sphygmomanometer

  • Sphygmomanometer uses

  • How to use a sphygmomanometer?


A sphygmomanometer is a word derived from the Greek word sphygmos which means beating of the heart or the pulse. By adding two words sphygmos + manometer,  a word sphygmomanometer was formed.

It is an instrument that measures blood pressure that contains an inflatable rubber cuff, which is cloaked around the arm. A measuring device indicates the cuff's pressure or tension, especially in arteries.

Types of a Sphygmomanometer

There are three types of sphygmomanometers that are used to gauge human blood.

Mercury sphygmomanometer

The mercury sphygmomanometer is considered the “gold standard” among all other types of devices representing the classic and time-tested method of assessing blood pressure.

The device consists of an inflatable bladder along with a column of mercury. Varying pressures cause different levels of mercury in the column. Once the column is made, recalibration is not required to take place to their exactness.

Aneroid Sphygmomanometer

The aneroid sphygmomanometer is a device that stands on the stans or walls,  consists of a spring device and metal membrane that translates the signals from the cuff and operates a needle in the gauge. The absence of a liquid provides mobility, as this device can be moved easily from one location to another. Since these devices require calibration checks that’s why they provide imprecise results. The needle has to be kept to zero before its use. The accurate results are possible by frequent calibrations.

Digital Sphygmomanometer

When you want to measure the blood pressure at your home effortlessly, the diastolic and systolic blood pressure, the digital sphygmomanometer comes out to be handy without preparations. You just need to connect the node of the rubber inside the hole of the monitor and cloak the cuff around your upper arm, as you click on the button, it would evaluate your bp and heart rate by means of oscillometric detection. The monitor has an audio device inbuilt to tell you the results in accordance with the WHO standards. The best part of having such a device is, it is portable and has expediency, it can be charged and we can also see the average results. 

Diagram of Sphygmomanometer

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Parts of a Sphygmomanometer

Bladder:  It is an inflatable bag that, when filled squeezes the arms to block the artery.

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Cuff:  The cuff has an inflatable rubber bladder that is cloaked around the upper arm. A pressure meter indicates the cuff's pressure.

Valve: The deflation valve allows for controlled deflation of the cuff and it’s critical for accurate measurement. An end check valve prevents air from escaping.

Bulb:  A small, handheld air pump inflates the blood pressure inside the cuff.

Manometer: It is the portion of the sphygmomanometer that measures the blood pressure in mmHg. This aneroid gauge contains a watch-like movement that measures the air pressure applied to the cuff. Within the gauge, there is a series of diaphragms (of copper or beryllium) that expands when air is filled, contains gears that transform the linear motion of diaphragms, turning the needle on a dial calibrated in mmHg.

Uses of a Sphygmomanometer 

The sphygmomanometer is designed to monitor blood pressure by measuring the force of the blood in the heart where the pressure is highest.

A sphygmomanometer is used to establish a service line at a healthcare meet and on admission to a hospital. Examining blood pressure is also executed to supervise the potency of medication and other methods to curb hypertension and as a diagnostic aid to discover various diseases and abnormalities.

The use of Three Types of Sphygmomanometers are Described Below:

Aneroid Sphygmomanometer 

This device has a widespread utilization among health practitioners and medical experts.

Mercury Sphygmomanometer 

They are used in all the clinical tests of pharmaceuticals, and medical institutions, clinical judgments in order to evaluate the blood pressure more to those who are high-risk patients as well as pregnant women.

Digital Sphygmomanometer 

Due to inaccurate results, some healthcare providers use digital for screening but use mercury sphygmomanometers to corroborate readings in some situations.

How to use a Sphygmomanometer?

Following is the procedure to use this device:

  • Use the properly-sized bp cuff and the length of the cuff's bladder should be at least equivalent to 80% of the circumference of your upper arm.

  • Wrap the cuff around your upper arm and lightly press the stethoscope's bell over the brachial artery just below the cuff’s edge.

  • Inflate the sphygmomanometer (blood pressure cuff) to 180 mm Hg.

  • Slowly release air by mildly turning the air valve, and observe the pressure drop.

  • Listen with the stethoscope and simultaneously notice the mercury gauge. 

  • The first sound you hear via stethoscope, that will determine the systolic blood pressure.

  • Continue to watch the pressure drop, when you no longer hear any sound, that will be the Diastolic blood pressure.

FAQ (Frequently Asked Questions)

Q1: Do Home Blood Pressure Monitors need to be Calibrated?

The digital blood pressure monitor works automatically. It is essential to re-calibrate it at least once every two years to assure that it is giving you precise results. To have your home bp monitor recalibrated, you will need to send it back to the manufacturer.

Q2: How to Choose the Right Blood Pressure Monitor?

The size of the cuff is the most important characteristic to ascertain when you're choosing a blood pressure monitor. A cuff that doesn't fit properly on your arm may give you faulty readings. You need to be certain that your monitor is listed as ‘clinically validated’. This means that the digital monitor has gone through a sequence of tests to straight-up that it gives results that you and your doctor can trust.