Question

what special structure is on the posterior wall of the right atrium

Answer 1

The coronary sinus
The coronary sinus is the special structure located on the posterior wall of the right atrium. It is an important structure as it provides information on both left atrial and left ventricular activity without requiring a trans-septal approach (a technique for patients who have valvular disease). The coronary sinus serves as the primary collector of cardiac venous blood and it facilitates the movement of blood from the myocardium (a thick layer of muscle within the heart) into the right atrium. The coronary sinus also plays important roles when performing cardiac surgery and in other heart procedures.

Answer 2

Answer:

Coronary sinus

Explanation:

The coronary sinus has a length of 15 to 65 mm and they are found in the posterior part of the coronary sulcus which is located on the  posterior surface of heart. It acts as a primary collector of cardiac blood and then drains the blood into the right atrium. The cardiac blood is received from ventricular veins and the oblique vein of the left atrium.