These finger-like extensions represent the right auricle which is an extension of the cavity of the right atrium | The superior vena cava returns deoxygenated blood from the head and shoulders which enters from the right and left brachiocephalic veins | The inferior vena cave returns deoxygenated blood from the thorax, abdomen, and legs. | The aortic arch gives rise to the brachiocephalic artery, left common carotid artery, and left subclavian artery. | The pulmonary trunk gives rise to the right and leftt pulmonary arteries which go to the lungs. | The ligamentum arteriosum is a remnant of the fetal ductus arteriosus which bypasses the lungs by shunting blood from the pulmonary trunk to the aorta. | The left auricle, like the right, is an external ear-like flap which internally is continuous with the left atrium. | The left pulmonary veins bring oxygenated blood from the left lung into the left atrium. | The myocardium is supplied with blood from the right and left coronary arteries. | The (red) anterior interventricular artery and circumflex artery are branches from the left coronary artery and the marginal arteries are branches from the right coronary. | The (blue)great cardiac vein drains blood from the myocardium [See slide #8] and runs alongside the anterior interventricular artery in the interventricular sulcus.