Superior leaflet of right atrioventricular valve

The superior leaflet of the tricuspid valve (anterior cusp; infundibular cusp of the right atrioventricular valve) is the largest and most mobile of the tricuspid leaflets, occupying approximately 25–26% of the annular circumference in typical three-leaflet configurations. It is positioned anterosuperiorly in the right atrioventricular orifice, adjacent to the right ventricular free wall and the right atrial appendage vestibule, interposed between the atrioventricular orifice and the conus arteriosus.

The superior (anterior) leaflet is broad, triangular, and has a long free edge. It is supported by chordae tendineae arising predominantly from the anterior papillary muscle, which is the largest papillary muscle in the right ventricle. The leaflet also receives chordal attachments from the septum or small septal papillary muscles, contributing to its mobility and coaptation.

The leaflet's base is attached to the tricuspid annulus, which is nonplanar and dynamic, with the anteroseptal portion being the most atrial (highest) and the posteroseptal aspect being the most ventricular (lowest).