Coronary' sinus is guarded by -: (A) Crista terminal is, (B) Thebesian valve, (C) Mitral valve, (D) Spiral valve
Answer is B. Ans. is 'b' i.e., Thebesian valveo Thebesian valve (incomplete semilunar valve) guards the orifice of coronary sinus.Venous Drainage of Hearto 60 % through coronary sinus into right atriumo 40 % directly in chambers of the heart via.Anterior cardiac veinsThebesian vein or venae cordis minimiSometimes, the right marginal vein opens directly into right atriumCoronary Sinuso It is a 2-3 cm long venous channel present in left posterior part of coronary sulcuso It opens into the sinus venorum part of right atrium, the opening guarded by incomplete semilunar valveTributariesGreat cardiac vein : It runs in the anterior interventricular groove and receives the left marginal vein.Middle cardiac vein : It lies in the posterior interventricular groove.Small cardiac vein : It is present in the atrioventricular groove and usually receives the right marginal vein.Posterior vein of left ventricle : It drains the inferior surface of the left ventricle.Oblique vein of left atrium : It drains the posterior surface of left atrium (a remnant of the left duct of cuvier)Note : All the above veins are provided with valves except oblique vein of left atrium.