Anatomical considerations of the mitral valve are important while considering mitral valve repair either surgically or by percutaneous trans catheter techniques. The mitral valve complex consists of the mitral annulus, mitral valve leaflets, the chordae tendinae and the papillary muscles. The mitral leaflets are the anterior and posterior leaflets.
Scallops of the mitral valve
The posterior leaflet has three scallops named P1, P2 and P3. The commissures of the mitral valve are the anterolateral and the posteromedial commissures. The papillary muscles are the anterolateral and the posteromedial papillary muscles. The P1 scallop is near the anterolateral commissure and the P3 scallop is near the posteromedial commissure, with the P2 scallop in the middle. They are also called the lateral, central and medial scallops. Though the anterior leaflet does not have well defined scallops like the posterior leaflets, there are corresponding named segments known as A1, A2 and A3.
Primary, secondary and tertiary chordae
The chordae tendinae are of three types – primary, secondary and tertiary. Primary chordae attach to the tips of the mitral leaflets while the secondary chordae connect the rough zone of the leaflets to the papillary muscles. The secondary chords are are also known as strut chords. The tertiary chordae are attached to the basal region of the mitral leaflets and connect to the ventricular free wall. The tensing of the chordopapillary system during systole has an important role in the competence of the mitral valve in preventing regurgitation.