Frequently Asked Questions on Sphygmomanometers and Aneroids


What do Sphygmomanometers measure?

Sphygmomanometers register blood pressure using a mercury column.

What are the parts of a Sphygmomanometer?

Parts of a Sphygmomanometer:

  • Bulb - The bulb pumps air into the cuff. An end (check) valve prevents air from escaping.
  • Manometer - The portion of the sphygmomanometer that measures the air pressure in mmHg.
  • Cuff - The cuff is designed to hold the bladder around the limb during measurement.
  • Bladder - The bladder is the inflatable bag that, when filled, compresses the arm to occlude the artery.
How to check the accuracy of aneroid sphgymomanometer?

For accurate Measurement, it is not necessary for the gauge needle to rest at zero point but please make sure that the gauge needle should rest within the area of zero square prior to use. The zero square itself reflects the warranty for accuracy, i.e. ± 3 mmHg.

Should sphygmomanometer unit be calibrated periodically?

Yes, sphygmomanometer unit should be calibrated regularly for at least once a year.

How to choose the proper size cuff?

The wrong cuff size will lead to inaccurate blood pressure measurement since the initial pressure given for the measurement may vary depends on how large the arm circumference is. When the cuff size is right the white index line comes in the range between the arrows after the cuff has been put on.