The interatrial septum is the thin wall separating the right and left atria. It runs obliquely, facing forwards and to the right, and its most visible feature on the right side is the fossa ovalis, the remnant of the fetal foramen ovale. Defects in this wall are among the most common congenital heart problems found in adults.
| Location | Between the right and left atria, angled so that the left atrium lies behind and to the left of the right atrium. |
|---|---|
| Parts |
|
| Nerve Supply | Cardiac plexus; Vagus nerves (parasympathetic, slows rate); Sympathetic cardiac nerves from cervical and upper thoracic (T1-T4) ganglia (raise rate and force) |
| Blood Supply | Right coronary artery (atrial branches); Left circumflex artery (atrial branches) |
Separates oxygen-poor blood in the right atrium from oxygen-rich blood in the left atrium after birth. Before birth the foramen ovale in this septum lets oxygenated placental blood bypass the lungs.
Atrial septal defects allow left-to-right shunting that overloads the right heart and pulmonary circulation, often unnoticed until adulthood. The septum is deliberately punctured (transseptal puncture) to reach the left atrium during ablation for atrial fibrillation and other catheter procedures. Lipomatous hypertrophy of the septum is a benign fatty thickening seen on imaging.
A hole in the septum, most often of the secundum type at the fossa ovalis. Large defects cause right heart enlargement, arrhythmias and pulmonary hypertension and can be closed with a catheter device or surgery.
Failure of the flap of the foramen ovale to seal after birth, present in about a quarter of adults. It can allow clots to cross into the systemic circulation and is linked to some strokes and decompression illness in divers.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
