Posterior/ventricular/mural/smaller/posterolateral leaflet

The posterior leaflet is also known as the ventricular, mural, smaller, or posterolateral leaflet. The posterior leaflet is the section of the mitral valve that is located posterior to the 2 commissural areas. It has a wider attachment to the annulus than the anterior leaflet. It is divided into 3 scallops by 2 indentations or clefts. The middle scallop is larger than the other 2 (the anterolateral and posteromedial commissural scallops). The 3 zones on the posterior leaflets are referred to as rough, clear, and basal zones, according to the chordae tendineae insertion.

The rough zone is defined in the posterior leaflet. It is distal to the ridge of the line of the leaflet closure. It is broadest at the distal part of the scallops and tapers toward the clefts or indentations between the scallops. Like that of the anterior leaflet, the clear zone of the posterior leaflet is clear on transillumination and has no chordae tendineae insertion. It is located in the middle part of the posterior leaflet, between the rough zone and the basal zone. The basal zone is located between the clear zone and the mitral valve annulus and has the insertion of basal chordae tendineae. This zone is only seen in the posterior leaflet and is best visualized on the middle scallop (because most of the basal chordae insert into this scallop).

http://emedicine.medscape.com/article/1878301-overview#a2

--------------------------------------------------
Note added at 23 mins (2016-07-08 16:52:56 GMT)
--------------------------------------------------

El velo posterior de la valvula mitral tiene forma cuadrangular y se encuentra anclado a 3/5 partes de la circunferencia del anillo mtral. Posee dos indentaciones bien definidas, las culaes dividen el velo en tres segmentos identificados como P1 (segmento anterior o medial), P2 (segmento medio) y P3 (segmento posterior o lateral). Los tres segmentos correspondientes del velo anterior serian A1 (segmento anterior), A2 (segmento medio) y A3 (segmento posterior)1. Esta nomenclatura es de vital importancia para describir detalles anatomicos especificos entre ecocardiografistas y cirujanos. Las indentaciones del velo posterior permiten su apertura en diastole.

http://www.reparacionvalvularmitral.org/content/view/50/