Inferior leaflet of right atrioventricular valve

The inferior leaflet of the right atrioventricular valve (posterior cusp of tricuspid valve; mural, inferior leaflet)refers to the posterior (sometimes called mural or inferior) leaflet of the tricuspid valve. The tricuspid valve is anatomically variable, most commonly comprising three leaflets: anterior, septal, and posterior. However, recent anatomical studies have shown that up to 40% of human hearts possess a four-leaflet configuration, with the additional leaflet typically located in the most inferior region of the annulus, thus termed the "inferior leaflet".[1-2]

The annular attachment of the posterior leaflet is adjacent to the right ventricular free wall, and its tissue is thinner than that of the mitral valve leaflets.[3]

In the four-leaflet configuration, the inferior leaflet occupies approximately 12% of the annular circumference, and its commissures (inferomural and inferoseptal) are typically located near the right atrial appendage vestibule and cavotricuspid regions, respectively.[1] The inferomural region is noted to be the most anatomically variable area of the tricuspid valve, which has implications for surgical and transcatheter interventions.[1-2]