Foramen Ovale (heart)
In the fetal heart, the foramen ovale ( /fɒˈreɪmɨn oʊˈvæliː/), also foramen Botalli, ostium secundum of Born or falx septi, allows blood to enter the left atrium from the right atrium. It is one of two fetal cardiac shunts, the other being the ductus arteriosus (which allows blood that still escapes to the right ventricle to bypass the pulmonary circulation). Another similar adaptation in the fetus is the ductus venosus. In most individuals, the foramen ovale closes at birth. It later forms the fossa ovalis.
Read more about Foramen Ovale (heart): Development, Closure, Clinical Relevance