Sphygmomanometer : An instrument for measuring blood pressure, particularly in arteries. The two types of sphygmomanometers are a mercury column and a gauge with a gauge with a dial face.
Sphygmomanometer, instrument for measuring blood pressure. It consists of an inflated rubber cuff, which is wrapped around the upper arm and is connected to an apparatus that records pressure, usually in terms of the height of a column of mercury or on a dial (an aneroid manometer).
An arterial blood pressure reading consists of two numbers, which typically may be recorded as x/y. The x is the systolic pressure, and y is the diastolic pressure.
Systole refers to the contraction of the ventricles of the heart, when blood is forced from the heart into the pulmonary and systemic arterial circulation, and diastole refers to the resting period, when the ventricles expand and receive another supply of blood from the atria.
At each heartbeat blood pressure is raised to the systolic level, and, between beats, it drops to the diastolic level. As the cuff is inflated with air, a stethoscope is placed against the skin at the crook of the arm.
As the air is released, the first sound heard marks the systolic pressure; as the release continues, a dribbling noise is heard. This marks the diastolic pressure, which is department on the elasticity of the arteries.
Based on long- term experience, blood pressure measurement using the mercury sphygmomanometer is regarded as the gold standard method for indirect measurement of blood pressure.
The use of the mercury sphygmomanometer has practical and technical limitations, and requires specific training.
In 1881, Von Basch created the sphygmomanometer and the first non-invasive BP measurements. However, in 1896, Scipione Riva-Rocco developed further the mercury sphygmomanometer, almost as we know it today.