Anterior Sectional Anatomy of the Papillary Muscles of the Left Ventricle

Description

Anterior sectional anatomy through the left ventricle exposes the anterolateral and posteromedial papillary muscles (musculi papillares sinistri) projecting from the ventricular myocardium into the chamber lumen. Their trabeculated bases arise from the left ventricular free wall and adjacent interventricular septum, with muscle bellies oriented superiorly toward the mitral valve apparatus. Fine chordae tendineae extend from each papillary muscle apex to the anterior and posterior mitral leaflets, crossing the ventricular cavity in oblique, tension-bearing lines. Papillary muscle position and tethering geometry matter because mitral competence depends on synchrony between ventricular contraction, chordal tension, and leaflet coaptation at the annulus. Ischemia or infarction of the posteromedial papillary muscle, often supplied by the posterior descending artery from a right-dominant system, can precipitate acute severe mitral regurgitation or frank papillary muscle rupture with pulmonary edema. Surgeons and echocardiographers also track this anatomy when distinguishing primary leaflet pathology from functional regurgitation caused by left ventricular dilation and apical displacement of the papillary muscles, which increases tenting height and restricts leaflet closure. Cardiac anatomy instructors can place this image alongside parasternal long-axis echocardiography and short-axis MRI slices to teach how papillary muscle location shifts with imaging plane and why chordae tendineae appear as linear echogenic structures in the left ventricle. It also supports operative planning and illustrations for mitral valve repair techniques, including chordal replacement and papillary muscle approximation in ischemic mitral regurgitation. Anatomical accuracy verified by SciePro's Medical Advisory Board.