Understanding the Right Atrium: Function, Location, and Anatomy

The right atrium is a vital component of the heart, playing a crucial role in maintaining proper cardiac function. Located near the junction of the superior vena cava (SVC) and the right atrium, the right atrium is regulated by the vagus nerve and the cardiac sympathetic plexus. In this article, we will delve into the anatomy and function of the right atrium, exploring its location, blood flow, and relationship with other heart structures.

Location and Blood Flow

The right atrium is situated in a subepicardial location, surrounded by the tiny myocardial Thebesian veins that drain directly into the right atrium. The sinoatrial node artery, which arises from the second branch of the right coronary artery (RCA) in 60% of cases, provides blood supply to this region. Additionally, the right atrium receives blood from the superior vena cava (SVC), inferior vena cava (IVC), coronary sinus, and Thebesian veins.

Anatomy

The right atrium has a unique anatomy, with several notable features. The posterior wall is marked by the interatrial septum, which faces anteriorly and to the right, with a depression known as the fossa ovalis in its lower part. The upper end of the right atrium lies to the left of the SVC opening, representing the true auricular chamber of the embryonic heart.

The interior half of the chamber is smooth muscular ridge (musculi pectini) from the roof just in front of and below the SVC opening, extending along the lateral wall to the anterior lip of the IVC. The right atrial appendage overlies the aortic root and proximal RCA, forming an irregular ellipsoid shape with the exception of the auricle, which arises anteriorly.

Relationships with Other Heart Structures

The right atrium leads into the right ventricle through the tricuspid valve and is separated from the left atrium by the interatrial septum. In cases of congenital cardiac malformations, the morphologic right atrium can be identified by the fossa ovalis in the interatrial septum.

In summary, the right atrium is a vital component of the heart's anatomy and function, playing a crucial role in blood flow and circulation. Its unique location, blood supply, and relationships with other heart structures make it an essential part of maintaining proper cardiac function. By understanding the right atrium, we can better appreciate the complex mechanisms that govern our cardiovascular system.

Valva auricula derecha