1 — Right ventricle; 2 — Right ventricle, myocardium; 3 — Interventricular septum, membranous part; 4 — Tricuspid valve; Right atrioventricular valve, anterior and posterior cusp; 5 — Right atrioventricular orifice; 6 — Right atrium; 7 — Musculi pectinati; Pectinate muscles; 8 — Opening of inferior vena cava; 9 — Fossa ovalis; Oval fossa; 10 — Right superior and inferior pulmonary veins; Opening; 11 — Left atrium; 12 — Interatrial septum; 13 — Left pulmonary vein; 14 — Opening of coronary sinus; 15 — Left atrioventricular orifice; 16 — Mitral valve; Left atrioventricular valve, anterior and posterior cusp; 17 — Chordae tendineae; Tendinous cords; 18 — Left ventricle; 19 — Left ventricle, myocardium; 20 — Interventricular septum, muscular part; 21 — Apex of heart
