Figure 1.

An image obtained using virtual cardiac dissection (a) with one of the heart specimens sectioned in a comparable view (b). Both panels clearly demonstrate that the superior rim of the oval fossa is no more than the superior interatrial fold between the connections of the superior caval vein to the right atrium, and the right upper pulmonary vein to the left atrium. The oval fossa lies between this superior rim and the anteroinferior buttress, which anchors the fossa to the atrioventricular junction. ICV: Inferior caval vein, LA: Left atrium, RA: Right atrium, RAA: Right atrial appendage, RLPV: Right lower pulmonary vein, RPA: Right pulmonary artery