Sectional Presentation of the Left Atrioventricular Valve Chordae Tendineae

Description

Sectioned through the left atrioventricular junction, the mitral valve leaflets appear in profile with their free margins tethered by chordae tendineae. Primary (marginal) chordae insert along the leaflet edge, while secondary chordae attach more basally on the ventricular surface, creating a layered cordal pattern from cusp to papillary muscle. Anterior and posterior leaflets can be distinguished by their relative breadth and the distribution of chordal insertions, with cords coursing inferiorly into the left ventricle toward the anterolateral and posteromedial papillary muscles. Fine fibrous strands dominate. Mitral chordal anatomy matters because leaflet competence depends on correct tensioning during systole, and a small change in chordal length or rupture location produces a predictable regurgitant mechanism. Elongation or rupture of marginal chordae, common in myxomatous degeneration with prolapse or flail segments, contrasts with displacement of secondary chordae in functional (ischemic) mitral regurgitation where papillary muscles shift apically and laterally after infarction. For surgeons, this sectional presentation clarifies why chordal-sparing valve replacement preserves left ventricular geometry, and why targeted chordal replacement with expanded polytetrafluoroethylene sutures must respect native insertion points and leaflet scallop anatomy. Use it for teaching mitral valve mechanics in gross anatomy and cardiothoracic surgery modules, or for illustrating Carpentier functional classification in a cardiology text, echocardiography guide, or structural heart device briefing where chordal tethering and leaflet coaptation are discussed. It also suits patient-facing materials explaining chordal rupture and repair, provided terminology is adapted. Anatomical accuracy verified by SciePro's Medical Advisory Board.