Which structure is located posterior to the tricuspid valve?

Which structure is located posterior to the tricuspid valve?

• A. SA Node
• B. Coronary sinus ostium
• C. Fossa ovalis
• D. Right atrial appendage

Answer: (B)

The key idea is how the right atrium is organized posteriorly where the tricuspid valve sits between the right atrium and right ventricle. The coronary sinus runs in the posterior part of the heart, occupying the atrioventricular groove, and its opening into the right atrium—the coronary sinus ostium—is on the posterior wall of the right atrium, near where the tricuspid valve sits. That makes the coronary sinus ostium a structure located behind the tricuspid valve. In contrast, the SA node lies high at the boundary where the superior vena cava enters the right atrium, in a more anterosuperior location. The fossa ovalis is in the interatrial septum, not directly behind the tricuspid valve, and the right atrial appendage is on the anterior aspect of the right atrium. So the structure positioned posterior to the tricuspid valve is the coronary sinus ostium.

The key idea is how the right atrium is organized posteriorly where the tricuspid valve sits between the right atrium and right ventricle. The coronary sinus runs in the posterior part of the heart, occupying the atrioventricular groove, and its opening into the right atrium—the coronary sinus ostium—is on the posterior wall of the right atrium, near where the tricuspid valve sits. That makes the coronary sinus ostium a structure located behind the tricuspid valve.

In contrast, the SA node lies high at the boundary where the superior vena cava enters the right atrium, in a more anterosuperior location. The fossa ovalis is in the interatrial septum, not directly behind the tricuspid valve, and the right atrial appendage is on the anterior aspect of the right atrium. So the structure positioned posterior to the tricuspid valve is the coronary sinus ostium.