Interventricular septum

The interventricular septum is directed obliquely backward to the right and curved with the convexity toward the right ventricle; its margins correspond with the anterior and posterior interventricular sulci. The lower part of the septum, which is the major part, is thick and muscular, and its much smaller upper part is thin and membraneous.

During each cardiac cycle the interventricular septum contracts by shortening longitudinally and becoming thicker.

Structure

The interventricular septum is the stout wall separating the ventricles, the lower chambers of the heart, from one another.

The ventricular septum is directed obliquely backward to the right and curved with the convexity toward the right ventricle; its margins correspond with the anterior and posterior interventricular sulci. The greater portion of it is thick and muscular and constitutes the muscular interventricular septum. Its upper and posterior part, which separates the aortic vestibule from the lower part of the right atrium and upper part of the right ventricle, is thin and fibrous, and is termed the membranous ventricular septum.

Blood supply

The posterior interventricular artery, a branch of right coronary artery, supplies the posterior 1/3 of the interventricular septum. The remaining anterior 2/3 is supplied by the anterior interventricular artery, which is a septal branch of the left anterior descending artery, which is a branch of left coronary artery.