Answer:
Coronary Sinus
Explanation:
A coronary sinus is a group of small veins that collectively from the sinus which is nothing but a large sized vessel. This sinus is located along the rear side of heart between the left ventricle and left atrium.
This sinus collects cardiac venous blood which comes from the mycocardium and the thick muscle layer with in the heart and facilitates its movement to the right atrium.
