Vasculature Of The Heart

Although the heart chambers are filled with blood, it provides very little nourishment and oxygen to the tissues of the heart. The walls of the heart are too thick to be supplied by diffusion alone. Instead, the tissues of the heart are supplied by a separate vascular supply committed only to the heart. The arterial supply to the heart arises from the base of the aorta as the right and left coronary arteries (running in the coronary sulcus). The venous drainage is via cardiac veins that return deoxygenated blood to the right atrium.

The coronary arteries arise from the ostia in the left and right sinuses of the aortic semilunar valve, course within the epicar-dium, and encircle the heart in the atrioventricular (coronary) and interventricular sulci (Fig. 23).

8.1. Right Coronary Artery

The right coronary artery emerges from the aorta into the atrioventricular groove. It descends through the groove, then curves posteriorly, makes a bend at the crux of the heart, and continues downward in the posterior interventricular sulcus. Within millimeters after emerging from the aorta, the right coronary artery gives off two branches (Figs. 23 and 24). The conus (arteriosus) artery runs to the conus arteriosus (right ventricular outflow tract), and the atrial branch goes to the right atrium. This atrial branch gives off the sinoatrial nodal artery (in 50-73% of human hearts, according to various reports), which runs along the anterior right atrium to the superior vena cava, encircling it in a clockwise or counterclockwise direction before reaching the sinoatrial node. The sinoatrial nodal artery supplies the sinoatrial node, Bachman's bundle, crista terminalis, and the left and right atrial free walls.

The right coronary artery continues in the atrioventricular groove and gives off a variable number of branches to the right atrium and right ventricle. The most prominent of these is the right marginal branch, which runs down the right margin of the heart, supplying this part of the right ventricle. As the right coronary curves posteriorly and descends downward on the posterior surface of the heart, it gives off two to three branches. One is the posterior interventricular (posterior descending) artery, which runs in the posterior interventricular sulcus. It is directed toward the apex of the heart to supply the posterior free wall of the right ventricle. In 85-90% of human hearts, branches of this artery (posterior septal arteries) supply the posterior one-third of the interventricular septum (Fig. 25). The second artery is the atrioventricular nodal artery, which branches from the right coronary artery at the crux of the heart and passes anteriorly along the base of the atrial septum to supply the atrioventricular node (in 50-60 % of hearts), proximal parts of the bundles (branches) of His, and the parts of the posterior interventricular septum that surround the bundle branches. Another artery crosses the crux into the left atrio-ventricular groove to supply the diaphragmatic surface of the left ventricle and the posterior papillary muscle of the bicuspid valve.

LEFT coronary

Cardiac Vasculature

Fig. 23. Vascular supply to the heart. Arterial supply to the heart occurs via the right and left coronary arteries and their branches. Venous drainage occurs via cardiac veins. LAD, left anterior descending; SVA, superior vena cava.

interventricular (LAD)

Fig. 23. Vascular supply to the heart. Arterial supply to the heart occurs via the right and left coronary arteries and their branches. Venous drainage occurs via cardiac veins. LAD, left anterior descending; SVA, superior vena cava.

Vasculature The Heart

Fig. 24. Atrial branch of the right coronary artery. This atrial branch gives off the sinoatrial nodal artery, which runs along the anterior right atrium to the superior vena cava and encircles it in a clockwise, or sometimes counterclockwise, direction before reaching the sinoatrial node. The nodal artery can also pass intramurally through the right atrium to the sinoatrial node. The sinoatrial nodal artery supplies the sinoatrial node, Bachman's bundle, crista terminalis, and left and right atrial free walls.

Fig. 24. Atrial branch of the right coronary artery. This atrial branch gives off the sinoatrial nodal artery, which runs along the anterior right atrium to the superior vena cava and encircles it in a clockwise, or sometimes counterclockwise, direction before reaching the sinoatrial node. The nodal artery can also pass intramurally through the right atrium to the sinoatrial node. The sinoatrial nodal artery supplies the sinoatrial node, Bachman's bundle, crista terminalis, and left and right atrial free walls.

Lower Your Cholesterol In Just 33 Days

Lower Your Cholesterol In Just 33 Days

Discover secrets, myths, truths, lies and strategies for dealing effectively with cholesterol, now and forever! Uncover techniques, remedies and alternative for lowering your cholesterol quickly and significantly in just ONE MONTH! Find insights into the screenings, meanings and numbers involved in lowering cholesterol and the implications, consideration it has for your lifestyle and future!

Get My Free Ebook


Responses

  • Immacolata Capon
    What is the left ascending descending coronary artery drain to?
    5 years ago

Post a comment