Eustachian valve

Eustachian Valve

The Eustachian valve is a fold of thin, membranous tissue in the heart that directs the flow of blood from the inferior vena cava to the right atrium. It is a remnant of the fetal circulation system, specifically the venous duct, which loses its function after birth.

Anatomy[edit | edit source]

The Eustachian valve is located in the right atrium of the heart, near the opening of the inferior vena cava. It varies in size and shape among individuals, ranging from a small nodule to a large, crescent-shaped fold. Despite its variability, the Eustachian valve plays a crucial role in directing the flow of oxygen-depleted blood from the body to the right atrium.

Function[edit | edit source]

During fetal development, the Eustachian valve directs oxygen-rich blood from the inferior vena cava to the foramen ovale, a small hole in the interatrial septum. This allows the blood to bypass the non-functioning fetal lungs and proceed directly to the left side of the heart, from where it is pumped to the rest of the body.

After birth, the lungs begin to function, and the foramen ovale closes to form the fossa ovalis. The Eustachian valve then loses its original function, but continues to play a role in directing the flow of blood in the right atrium.

Clinical Significance[edit | edit source]

In some cases, the Eustachian valve may be unusually large or malpositioned, which can lead to health problems. For example, it may contribute to the formation of blood clots in the heart, which can lead to a stroke or other serious conditions. In other cases, a prominent Eustachian valve can be mistaken for an atrial septal defect, a hole in the wall between the two upper chambers of the heart.