ANATOMY

Detailed explanation-1: -The right atrium receives deoxygenated blood from the systemic circulation. The two major systemic veins, the superior and inferior venae cavae, and the large coronary vein called the coronary sinus that drains the myocardium, empty into the right atrium (Figs.

Detailed explanation-2: -Aside from the oblique vein of left atrium and the great cardiac vein, the coronary sinus also receives venous blood from the small and middle cardiac veins, and the posterior vein of the left ventricle.

Detailed explanation-3: -Function of the coronary sinus The CS is responsible for returning approximately 55% of the heart’s deoxygenated blood supply into the right atrium.