Pressure is force per unit area. Therefore its si unit the Pascal is N/m<sup>2</sup>. However it is common in physiology to use mmHg which is the measure of pressure at the bottom of a column of mercury of that height. | Pressure is force per unit area. Therefore its si unit the Pascal is N/m<sup>2</sup>. However it is common in physiology to use mmHg which is the measure of pressure at the bottom of a column of mercury of that height. |