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The pulmonary valve (sometimes referred to as the pulmonic valve) is a valve of the heart that lies between the right ventricle and the pulmonary artery, and has three cusps. It is one of the four valves of the heart and one of the two semilunar valves, the other being the aortic valve. Similar to the aortic valve, the pulmonary valve opens in ventricular systole when the pressure in the right ventricle rises above the pressure in the pulmonary artery. At the end of ventricular systole, when the pressure in the right ventricle falls rapidly, the pressure in the pulmonary artery closes the pulmonary valve.
The closure of the pulmonary valve contributes to the P2 component of the second heart sound (S2).
Structure
The pulmonary orifice lies nearly in the horizontal plane, and is situated at a superior level than the aortic orifice.
Cusps
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File:Lunules of semilunar leaflets of pulmonary valve.png
File:Anterior semilunar leaflet of pulmonary valve.png
File:Right semilunar leaflet of pulmonary valve.png
File:Left semilunar leaflet of pulmonary valve.png
File:Commissures of semilunar leaflets of pulmonary valve.png
File:Nodules of semilunar leaflets of pulmonary valve.png
</gallery>At the apex of the infundibulum, the pulmonary orifice is guarded by three semilunar cusps - two anterior and one posterior, with free edges projecting upward into the lumen of pulmonary trunk. The cusps are named according to their positions during foetal development: the anterior, the posterior, and the septal cusp.