Mnemonic: CAT
1. Coronary sinus (50%): Drains blood from left side of heart → Thebesian valve → Right Atrium
- Location: Posterior coronary (atrio-ventricular) sulcus
- Tributaries:
- Left marginal vein → Great cardiac vein (anterior interventricular sulcus) → Coronary sinus
- Right marginal vein → Small cardiac vein (right posterior coronary sulcus) → Coronary sinus
- Middle cardiac vein (posterior interventricular sulcus) → Coronary sinus
- Oblique vein of left atrium (oblique vein of Marshall)
- Posterior vein of left ventricle
2. Anterior cardiac veins (20%): Drain blood from right side of heart → Right Atrium
- Location: Right anterior coronary sulcus
3. Thebesian veins/Venae cordis minimi (30%): Drain deoxygenated blood from endocardium and myocardium → Respective chamber of heart