Millimetre of mercury

<p>A millimetre of mercury is a <a href="/facts/Pressure_measurement/fJrvoTDU">manometric</a> <a href="/facts/Unit_of_measurement/pvTpWbmC">unit</a> of <a href="/facts/Pressure/eyc37GRG">pressure</a>, formerly defined as the extra pressure generated by a column of <a href="/facts/Mercury_(element)/WlxfoHva">mercury</a> one <a href="/facts/Millimetre/25mdTXpa">millimetre</a> high. Currently, it is defined as exactly 133.322387415 <a href="/facts/Pascals/Am1To2Qm">pascals</a>, or approximately 1 <a href="/facts/Torr/Y83YBu34">torr</a> = ⁠1/760⁠ <a href="/facts/Standard_atmosphere_(unit)/aTbYALII">atmosphere</a> = ⁠101325/760⁠ pascals. It is denoted mmHg or mm Hg.
</p><p>Although not an <a href="/facts/International_System_of_Units/S7YLglNz">SI</a> unit, the millimetre of mercury is still often encountered in some fields; for example,  it is still widely used in <a href="/facts/Medicine/2fnp90Je">medicine</a>, as demonstrated for example in the <a href="/facts/Medical_literature/C01NYutX">medical literature</a> indexed in <a href="/facts/PubMed/JlHAvMHt">PubMed</a>. For example, the U.S. and European guidelines on <a href="/facts/Hypertension/wlAvBfcf">hypertension</a>, in using millimeters of mercury for <a href="/facts/Blood_pressure/VtqqSM2J">blood pressure</a>, are reflecting the fact (common basic knowledge among health care professionals) that this is the usual unit of blood pressure in clinical medicine.
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Millimetre of mercury open-in-new

Millimetre of mercury