Answer
The three major veins that drain into the coronary sinus are the great cardiac vein, the posterior interventricular vein, and the left marginal vein.
Work Step by Step
The great cardiac vein, the posterior interventricular vein, and the left marginal vein each dump blood into the coronary sinus.
The great cardiac vein runs along the anterior interventricular artery and collects blood from the anterior side of the heart. The posterior interventricular vein runs in the posterior interventricular sulcus and collects blood from the posterior side of the heart. The left marginal vein runs from near the apex up the left margin of the heart.
Each of these three coronary veins dumps blood into the coronary sulcus on the posterior side of the heart.
(pg 719)
