Scipione Riva-Rocci and the men behind the mercury sphygmomanometer.

The history of the blood pressure (BP) concept and measurements is described. Many scientists were involved. Among them, major triumphs were achieved by William Harvey during the early 1600s who announced that there is a finite amount of blood that circulated the body in one direction only. In the mid-1700s, Reverend Stephen Hales reported the first invasive measurement in horses and smaller animals. Poiseuille introduced in the early 1800s the mercury hydrodynometer and the mmHg units. Karl von-Vierordt described in 1855 that with enough pressure, the arterial pulse could be obliterated. He also created the sphygmograph, a pulse recorder usable for routine non-invasive monitoring on humans. In 1881, von Basch created the sphygmomanometer and the first non-invasive BP measurements. However, in 1896, Scipione Riva-Rocci developed further the mercury sphygmomanometer, almost as we know it today. The sphygmomanometer could only be used to determine the systolic BP. Observing the pulse disappearance via palpitation would only allow the measuring physician to observe the point when the artery was fully constricted. Nikolai Korotkoff was the first to observe the sounds made by the constriction of the artery in 1905.