Presentation of the Mitral Valve (Left Heart), Lateral View

Description

Seen in lateral section through the left heart, the mitral (bicuspid) atrioventricular valve sits between the left atrium superiorly and the left ventricle inferiorly, with the anterior (aortic) leaflet lying more anterosuperior and the posterior leaflet positioned more posteroinferior along the ventricular inflow. Chordae tendineae course distally from the free margins of both leaflets to the papillary muscles within the left ventricle. From this periphery-facing angle, the paired papillary muscle groups appear as superior and inferior muscular components on the ventricular wall, aligned to tension the chordae during systole. Trabeculae carneae and the ventricular endocardial surface form the background of the chamber. A lateral view like this clarifies the subvalvular apparatus, the part of the mitral complex most often underappreciated when learners focus only on leaflets. Rupture or elongation of chordae, or papillary muscle ischemia after an inferoposterior myocardial infarction, can produce acute mitral regurgitation with a flail leaflet, and this relationship between leaflet edge, chordae, and papillary base is the anatomy you need in mind when interpreting an eccentric regurgitant jet on echocardiography. The superior and inferior papillary groupings also map cleanly to the anterolateral and posteromedial papillary muscles, a distinction with real consequences because the posteromedial muscle commonly has a single coronary supply. Use this asset in cardiothoracic anatomy teaching when introducing the left atrioventricular valve, in pathology figures on mitral regurgitation or prolapse, or in surgical education materials addressing mitral valve repair maneuvers such as chordal replacement and papillary muscle repositioning. It also fits imaging-correlative layouts pairing gross sections with TEE long-axis concepts. Anatomical accuracy verified by SciePro's Medical Advisory Board.