Pulmonary stenosis is most commonly found in which anatomical region?

• A. Pulmonary valve
• B. Right atrium
• C. Infundibular region
• D. Aortic valve

Answer: (C)

Pulmonary stenosis most often arises in the infundibular region, the muscular outflow tract just below the pulmonary valve. This subvalvular narrowing occurs when the infundibulum thickens or develops muscular bands that constrict blood flow from the right ventricle into the pulmonary artery. It’s a common finding in conditions like Tetralogy of Fallot, where the infundibulum contributes significantly to the degree of right ventricular outflow obstruction. While the pulmonary valve itself can be narrowed (valvular stenosis) or, less commonly, the region above the valve (supravalvular) can be involved, the infundibular area is the typical site of greatest obstruction in many congenital cases.