Lateral Contour of the Left Side of the Cardiac Section

Description

Seen in lateral section, the left cardiac contour is formed chiefly by the left ventricle tapering to the apex cordis, with the left atrium lying superior and posterior to it and contributing to the cardiac base. Between the chambers, the interventricular septum occupies a medial position, its muscular part extending toward the apex while the smaller membranous septum sits superiorly near the atrioventricular junction. The mitral annulus and adjacent fibrous skeleton would be expected at the left atrioventricular orifice, with the aortic root arising superiorly and slightly medial to the left ventricular outflow tract. Orientation reads cleanly. For teaching, this cut clarifies where septal tissue changes from muscular to membranous, an anatomic hinge point that explains why perimembranous ventricular septal defects cluster just beneath the aortic valve and near the septal leaflet of the tricuspid valve (on the right side, not opened here). Electrophysiology and operative planning also depend on this neighborhood, since the atrioventricular conduction axis courses along the membranous septum and can be injured during VSD closure or aortic valve surgery. Small distances matter. Use this image in cardiothoracic anatomy and pathology modules to pair gross relationships with echo or CT concepts of the left ventricle, left atrium, and septal compartments, or in surgical texts illustrating septal defect repair, aortic root procedures, and the left ventricular outflow tract. It also fits patient-facing publisher graphics when explaining why a murmur from a septal defect is not located at the cardiac apex. Anatomical accuracy verified by SciePro's Medical Advisory Board.