Commissural leaflets

The commissural leaflets of the mitral valve are the small leaflet segments located at the junctions (commissures) between the anterior and posterior mitral leaflets, specifically at the anterolateral and posteromedial commissures. These regions are not true separate leaflets but are transitional zones where the anterior and posterior leaflets meet and coapt. The commissures are supported by chordae tendineae arising from the anterolateral and posteromedial papillary muscles, which insert into both the anterior and posterior leaflets at these junctions, providing structural support and ensuring proper leaflet coaptation during systole.