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 idea to grasp is how structures sit within the right atrium relative to the tricuspid valve. The tricuspid valve forms the boundary between the right atrium and right ventricle, and behind that valve lies the posterior wall of the right atrium where the coronary sinus drains into the heart. The opening of the coronary sinus, the coronary sinus ostium, sits on that posterior aspect of the right atrial wall near the tricuspid annulus, making it the structure located posterior to the valve. In contrast, the SA node is positioned high in the right atrium near the opening of the superior vena cava, which is more anterior. The fossa ovalis is on the interatrial septum, not behind the tricuspid valve. The right atrial appendage is an anterior projecting pouch. So the coronary sinus ostium is the structure located posterior to the tricuspid valve.

The idea to grasp is how structures sit within the right atrium relative to the tricuspid valve. The tricuspid valve forms the boundary between the right atrium and right ventricle, and behind that valve lies the posterior wall of the right atrium where the coronary sinus drains into the heart. The opening of the coronary sinus, the coronary sinus ostium, sits on that posterior aspect of the right atrial wall near the tricuspid annulus, making it the structure located posterior to the valve.

In contrast, the SA node is positioned high in the right atrium near the opening of the superior vena cava, which is more anterior. The fossa ovalis is on the interatrial septum, not behind the tricuspid valve. The right atrial appendage is an anterior projecting pouch. So the coronary sinus ostium is the structure located posterior to the tricuspid valve.