Sectional Placement of the Interventricular Septum

Description

Anterior to posterior, the section cuts through the cardiac ventricles and centers on the interventricular septum (septum interventriculare) as a thick partition between the right and left ventricular cavities. The muscular interventricular septum occupies the inferior and larger portion, while the membranous interventricular septum lies superiorly near the atrioventricular junction, adjacent to the right fibrous trigone and the septal leaflet of the tricuspid valve. Left ventricular myocardium appears thicker and more concentric, with the right ventricular wall thinner and more trabeculated, and the septal surface forming the medial wall of the right ventricle and the medial boundary of the left ventricle. Spatial relationships are clear. Clinical relevance concentrates at the superior septum, where a small membranous defect produces a classic perimembranous ventricular septal defect with left to right shunting and a harsh holosystolic murmur at the left lower sternal border. Conduction tissue tracks close by: the atrioventricular bundle (bundle of His) traverses the membranous septum before dividing into bundle branches along the septal endocardium, a point that matters during VSD closure, aortic valve surgery, and septal myectomy when iatrogenic complete heart block is a real risk. The anterior sectional orientation also mirrors how learners interpret short-axis cardiac imaging, where septal thickness and contour help distinguish hypertrophic cardiomyopathy from right ventricular pressure overload. Cardiac anatomy courses use this plate to teach septal composition, ventricular wall thickness, and the relationship of the membranous septum to the tricuspid and aortic valve apparatus. It also fits congenital heart disease chapters, operative atlases covering VSD patch placement, and cardiology education materials that correlate septal anatomy with echocardiographic and CT/MR cardiac sections. Anatomical accuracy verified by SciePro's Medical Advisory Board.