Coronary Sinus The structure indicated is the coronary sinus. The coronary sinus lies posteriorly on the heart in the coronary sulcus and receives four cardiac veins: Great cardiac vein Middle cardiac vein Small cardiac vein Posterior cardiac veins The coronary sinus returns deoxygenated blood to the right atrium of the heart, together with the superior and inferior vena cavae. Learn more about the anatomy of the venous drainage of the heart in this tutorial.
Great Saphenous Vein The structure indicated is the great saphenous vein. The great saphenous vein is a large superficial vein (the longest vein in the human body), which begins from the medial aspect of the dorsal venous arch of the foot. It then passes anteriorly, in front of the medial malleolus and ascends medially up the lower limb to drain into the femoral vein in the femoral triangle. Learn about the femoral triangle in this anatomy tutorial. Learn about the veins of the body in this tutorial.
Azygos Vein The structure indicated is the azygos vein. The azygos system of veins includes: Azygos vein Hemiazygos vein Accessory hemiazygos vein The azygos vein runs in the posterior mediastinum, on the right side of thoracic vertebral column. It drains into the superior vena cava, and transports deoxygenated blood from the posterior walls of the thorax and the abdomen. The azygos system forms important anastamotic connections, which serve to return blood to the heart via the superior vena cava, if the inferior vena cava becomes obstructed.