The arteries that supply the heart are coronary arteries; the veins of the heart are known as the cardiac veins.
The right and left coronary arteries originate from the aorta just above its origin from the left ventricle. The right coronary artery originates from the right aortic sinus and passes to the right, behind the pulmonary trunk, to run downward in the coronary sulcus between the right atrium and the right ventricle. It then turns posteriorly around the right margin of the heart and continues in the coronary sulcus. This artery and it's branches supply the right ventricle and the right atrium. The posterior interventricular branch runs in the interventricular sulcus toward the apex and supplies the diaphragmatic surface of both ventricles and a small portion of the interventricular septum. Some smaller branches of the right coronary artery include: marginal artery, sinoatrial branch, atrioventricular branch, and the conus arteriosus.
Theleft coronary artery originates from the left aortic sinus. Shortly after its origin this artery splits (bifurcates) into an anterior interventricular branch and a circumflex branch. The anterior interventricular branch runs along the left margin of the pulmonary trunk and descends toward the apex in the anterior interventricular sulcus. It supplies both ventricles, including the conus arteriosus, and a majority of the interventricular septum. The circumflex branch ultimately runs toward the left coronary artery in the coronary sulcus, however, first it runs between the left auricle and left ventricle, and then circles to the posterior aspect of the heart. Some of the named branches of the circumflex artery include: posterior left ventricular branch, marginal, an intermediate, and sometimes a sinoatrial and atrioventricular branch.
A majority of the cardiac blood that is collected from the myocardium is by veins that parallel the arteries. These cardiac veins come together to terminate into the coronary sinus, a large vein that empties into the right atrium. A small amount of blood is returned from the myocardium by small veins that empty directly into the four chambers of the heart.
The great cardiac vein runs in the anterior interventricular sulcus and drains upward alongside the anterior interventricular branch of the left coronary artery. As it reaches the coronary sulcus, it turns to the left to run with the circumflex branch of the artery. The great cardiac vein becomes continuous with the coronary sinus at the point where the oblique vein of the left atrium enters. The coronary sinus ends in the posterior wall of the right atrium. Very close to its ending, the coronary sinus receives the middle and small cardiac veins. The middle runs in the posterior interventricular sulcus and the small in the coronary sulcus along the right coronary artery. The posterior vein of the left ventricle drains the diaphragmatic surface of the ventricle and enters the coronary sinus soon after the sinus is formed.
As mentioned, there are also veins that dump directly into the heart. Several anterior cardiac veins, which arise on the anterior surface of the right ventricle and pass across the coronary sulcus to penetrate the anterior wall of the right atrium. In the muscular walls of the heart there are very small veins, least cardiac veins. These veins empty directly into the cardiac chambers. These small veins are thought to be most numerous in the right atrium and least numerous in the left ventricle.
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