Fossa ovalis (heart)


 * ''For the structure in the thigh, see Fossa ovalis (thigh).

Overview
Found in the right atrium of the heart, the fossa ovalis is an embryonic remnant of the foramen ovale, which normally closes shortly after birth. During adult life, it is seen as an oval depression in the inferior part of the interatrial septum. The floor of the foramen ovale constitutes the fused wall of the septum primum. Occasionally, fusion is incomplete and the superior part of the floor shows a communication through to the left atrium and this is known as a patent foramen ovale.

At the superior margin of the fossa ovalis is the limbus fossae ovalis.

Clinical significance
Failure of the foramen ovale to close results in a disorder known as patent foramen ovale.