What is the primary measurement taken by a sphygmomanometer expressed in?

The primary measurement taken by a sphygmomanometer, which is used to measure blood pressure, is expressed in millimeters of mercury (mmHg). This unit originates from the historical use of mercury in barometers and sphygmomanometers, where the pressure exerted by the blood on the walls of the arteries is compared to the height of a column of mercury.

Using mmHg allows for a standardized and recognized way to express blood pressure readings, facilitating clear communication among healthcare professionals and ensuring consistency in the measurement process. This unit is widely used in clinical settings globally, making it an essential knowledge area for those in the medical assisting field. Other measurements such as centimeters of water, pascals, and milligrams per deciliter are not typically used for representing blood pressure; they are relevant in other contexts, such as fluid pressure, general pressure measurements, and blood glucose levels, respectively.