Body of right atrium

The body of the right atrium is the central portion of the right atrial chamber, excluding the appendage, venous inflow tracts, and vestibule. It is bounded by the orifices of the superior and inferior vena cavae posteriorly, the tricuspid valve annulus inferiorly and anteriorly, and the interatrial septum medially. The body is characterized by a relatively smooth endocardial surface, in contrast to the trabeculated right atrial appendage.