This document discusses the anatomy and clinical applications of the coronary sinus and its tributaries. It notes that 60% of venous blood from the heart drains into the right atrium via the coronary sinus. The coronary sinus receives blood from the left coronary territory, while the anterior cardiac vein drains blood from the right coronary artery. Echocardiography, fluoroscopy, CT, and angiography can be used to image the coronary sinus and evaluate anomalies such as an absent or membranous Thebesian valve, absent tributaries, or an obstructed or dilated coronary sinus.