What is fossa ovale?

The fossa ovale is a small, oval-shaped depression located in the interatrial septum of the heart, specifically in the right atrium. It is the remnant of the foramen ovale, a fetal structure that allows blood to bypass the non-functioning lungs by flowing directly from the right atrium to the left atrium during fetal development. After birth, the foramen ovale usually closes, leaving the fossa ovale as a permanent feature of the heart's anatomy. Its presence is important in understanding certain cardiac conditions and potential complications.