Blood vessels of the heart (coronary arteries)

Blood vessels of the heart (coronary arteries)

Arteries are blood vessels carrying oxygenated blood to various parts of the body from the heart. Coronary arteries are blood vessels supplying oxygenated blood to the heart itself for the muscular pump to function. Two coronary arteries, right and left, arises from the root of aorta. Aorta is the largest blood vessel arising from the left ventricle the largest muscular chamber of the heart. Root of aorta has three bulges known as sinuses of Valsalva. Coronary arteries arise from these sinuses. The sinus from which right coronary artery arises is known as right coronary sinus and that from which the left coronary artery arises, the left coronary sinus. The sinus from which no coronary artery arises is known as non-coronary sinus.

Left coronary artery branches into left circumflex (LCX) and left anterior descending (LAD) coronary arteries. Since both these are major branches, they are considered as separate vessels and the left main given a separate designation. Left anterior descending coronary artery is often called the widow-maker artery because occlusion of this vessel near its origin causes a massive heart attack, myocardial infarction, which can be very often fatal. Sometimes one more branch arises from the left main coronary artery (LMCA) known as the ramus intermedius, called so because it arises in between the other two branches.

Left circumflex coronary artery lies in the atrioventricular groove, the groove between the upper chambers known as atria and the lower chambers known as ventricles, and gives off major branches known as obtuse marginals (OM). Left atrial circumflex is a branch of the left circumflex coronary artery, which supplies the sinus node, the pacemaker of the heart in a few cases. When the Left circumflex coronary artery is dominant, it crosses the crux and gives off the posterior descending artery (PDA) and posterior left ventricular branches (PLV). Crux is the junction of the grooves between the atria and ventricles and the atrioventricular groove, behind the heart.

Left anterior descending artery descends in the anterior interventricular groove. It gives off septal branches into the interventricular septum and diagonal branches which supply the lateral wall of the left ventricle. Interventricular septum is the partition between the ventricles, the lower muscular chambers of the heart.

Right coronary artery (RCA) is usually the dominant artery which crosses the crux, the junction of atrioventricular and interventricular grooves posteriorly. Hence the posterior descending artery and posterior left ventricular branches often arise from the right coronary artery. The first two branches of the right coronary artery are the sinus node artery and the conus artery. Conus artery supplies the upper most part of the right ventricle known as the conus, which is just below the pulmonary artery which arises from the right ventricle. Right coronary artery also gives off right ventricular branches and acute marginal branches. The atrioventricular nodal artery arises from the right coronary artery if is dominant, usually from its genu where it becomes the posterior descending artery. Right margin of the heart is known as the acute margin because it is less slanting and more vertical while the left margin of the heart is known as the obtuse margin because it is more slanting.