The three fetal shunts: A story of wrong eponyms.

The fetal circulatory system bypasses the lungs and liver with three shunts. The foramen ovale allows the transfer of the blood from the right to the left atrium, and the ductus arteriosus permits the transfer of the blood from the pulmonary artery to the aorta. The ductus venosus is the continuation of the umbilical vein, allowing a large part of the oxygenated blood from the placenta to join the supradiaphragmatic inferior vena cava, bypassing the fetal liver and directly connecting the right atrium. These structures are named after the physicians who are thought to have discovered them. The foramen ovale and the ductus arteriosus are called the "foramen Botalli" and the "ductus Botalli," after Leonardo Botallo (1530-c. 1587). The ductus venosus is styled "ductus Arantii" after Giulio Cesare Arantius (1530-1589). However, these eponyms have been incorrectly applied as these structures were, in fact, discovered by others earlier. Indeed, the foramen ovale and the ductus arteriosus were described by Galen of Pergamon centuries earlier (c. 129-210 AD). He understood that these structures were peculiar to the fetal heart and that they undergo closure after birth. The ductus venosus was first described by Andreas Vesalius (1514-1564) 3 years before Arantius. Therefore, the current anatomical nomenclature of the fetal cardiac shunts is historically inappropriate.