The coronary sinus -
Development of coronary sinus is from the body and left horn of sinus venosus. It lies in the posterior part of the coronary sulcus and drains into the right atrium. Though the besian veins/ venae cordis minimae drain directly into the right atrium, the the besian valves are guarding the opening of coronary sinus into the right atrium.
Lies in anterior part of the coronary sulcus
Ends in right atrium
Has venae cordis minimae as its tributaries
Develops from right anterior cardinal vein