The pulmonary valve or pulmonic valve (PV) is one of the four cardiac valves. It is the semilunar valve that allows blood to exit the right ventricle (RV). It opens during systole and closes during diastole.

The valve has anterior, left and right cusps, the bases of which attach around the valve orifice to a fibrous ring or annulus, forming part of the fibrous skeleton of the heart. The cusps attach to each other and the annulus at the commissures. The free edge of each cusp (lunule) is thickened where it contacts the free edges of adjacent cusps and at the angulated apex of each free edge there is further nodular thickening, known as the nodule. The cusps bulge inferiorly into the outflow tract of the right ventricle.

Immediately superior to the cusps, the pulmonary trunk is mildly dilated forming the pulmonary sinuses, the spaces between the dilated wall of the pulmonary trunk and the cusps of the semilunar valve. During systole these sinuses prevent the cusps from flattening against the walls of the sinuses, which may restrict valve closure during diastole. The pulmonary valve lies horizontally and is superior and to the left of the aortic valve (AV).

The relationship of the aortic valve to the pulmonary valve can be recalled by the mnemonic: PALS: P = pulmonary valve, A = anterior, L = lateral, S = superior. The pulmonary valve is anterior, lateral and superior to the aortic valve.

Related pathology

• pulmonary stenosis
• pulmonary atresia
• transposition of the great arteries
• tetralogy of Fallot