Counterpressure: the concept that made the indirect measurement of blood pressure possible

Blood pressure is measured noninvasively every medical examination. It is also measured routinely throughout the course of nearly all illnesses, and we all take this measurement for granted. Yet the ability to make this measurement is due to the creative genius of Etienne Jules Marey, a French physiologist, who, in 1876, applied the concept of using counterpressure to measure blood pressure noninvasively in humans. This article describes his original experiments and briefly summarizes evolution of the technology to its present state.