Registered Cardiovascular Invasive Specialist (RCIS) Practice Test

Where is the Eustachian valve located?

1. Between the inferior vena cava and the right atrium

2. At the entrance of the left atrium

3. In the left ventricle

4. At the junction of the aorta and pulmonary artery

The correct answer is: Between the inferior vena cava and the right atrium

The Eustachian valve is primarily located between the inferior vena cava and the right atrium. This valve is a remnant of the embryonic development of the heart, and its primary function is to help direct blood flow during fetal life. In the fetus, it shields the opening of the inferior vena cava from the high-pressure blood coming from the placenta, directing the flow toward the foramen ovale, which connects the right atrium to the left atrium. Although in postnatal life, the Eustachian valve is often non-functional, its presence is still anatomically noted in the adult heart. The other options refer to structures that do not house the Eustachian valve. The entrance of the left atrium (the second choice) pertains to the pulmonary veins and does not involve the Eustachian valve. The left ventricle (the third choice) is responsible for pumping oxygenated blood to the body and lacks the Eustachian valve entirely. The junction of the aorta and pulmonary artery (the fourth choice) involves the valves that regulate blood flow from the ventricles to the major arteries, but it does not deal with the Eustachian valve. Thus, the correct location identified helps