The interventricular septum (IVS, or ventricular septum, or during development septum inferius) is the stout wall separating the ventricles, the lower chambers of the

heart The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon diox ...

, from one another. The ventricular septum is directed obliquely backward to the right and curved with the convexity toward the

right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper ...

; its margins correspond with the

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

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

, from one another. The ventricular septum is directed obliquely backward to the right and curved with the convexity toward the

; its margins correspond with the

and posterior longitudinal 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 The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves. There are two a ...

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.

Development

The muscular part of the interventricular septum derives from the bulboventricular flange which is developed due to differential growth of primitive ventricle and bulbous cordis. Membranous part has a neural crest origin which connects the upper free margin of the bulboventricular flange and anterior and posterior endocardial cushions of atrio ventricular canal. It also gets attached to lower border of spiral septum or the aorticopulmonary septum. In the final stages of the heart development, the interatrial septum aligns in the same plane as the interventricular septum. The gap between the interatrial septum and interventricular septum forms the membranous part of interventricular septum.

Clinical significance

A ventricular septal defect (VSD), a hole in the interventricular septum is one of the four congenital defects of the condition of

tetralogy of Fallot Tetralogy of Fallot (TOF), formerly known as Steno-Fallot tetralogy, is a congenital heart defect characterized by four specific cardiac defects. Classically, the four defects are: * pulmonary stenosis, which is narrowing of the exit from the r ...

. A VSD can cause a left-to-right shunt of blood flow in the heart and is one of the most common of the congenital heart defects. This type of shunt is an acyanotic disorder that can result in ventricular hypertrophy. The alignment of interventricular septum and interatrial septum is disturbed in various congenital heart diseases.

Additional images

File:Heart normal short axis echo.svg, Heart normal short axis echo

References

External links

* - "Heart and semilunar valve" {{Authority control Embryology of cardiovascular system