What are the three branches of the coronary arteries?

There are many types of diseases surrounding human coronary arteries, such as coronary artery stenosis or coronary artery atherosclerosis, etc. There are many factors that affect these diseases, such as some physical factors, metabolic factors, neural factors, humoral factors, etc. In order to avoid the corresponding coronary artery disease, everyone should take preventive measures. Before that, you should understand the relevant knowledge about coronary arteries in detail. The following introduces the three branches of the coronary arteries.

The three branches of the coronary arteries are:

The left and right coronary arteries are the first pair of branches of the ascending aorta.

The left coronary artery is a short trunk that originates from the left aortic sinus, passes between the origin of the pulmonary artery and the left atrial appendage, and immediately divides into the anterior interventricular branch and the circumflex branch after running 3 to 5 mm to the left along the coronary groove. The anterior interventricular branch descends along the anterior interventricular groove, bypasses the apical notch, and anastomoses with the posterior interventricular branch of the right coronary artery on the diaphragmatic surface of the heart. Issued along the way:

(1) Conus arteriosus branch, distributed to the conus arteriosus;

(2) The lateral branch is distributed in most of the left ventricular anterior wall and the right ventricular anterior wall near the anterior interventricular groove;

(3) Septal branches: distributed in the anterior 2/3 of the ventricular septum. The circumflex branch runs to the left along the coronary sulcus, and when it passes the obtuse edge of the heart, it gives off a thick left marginal branch that is distributed to the lateral edge of the left ventricle; when it reaches the back of the heart, it gives off smaller branches that are distributed to the left atrium and left ventricle. The right coronary artery originates from the right aortic sinus, passes between the root of the pulmonary artery and the right atrial appendage, runs along the right coronary groove, bypasses the right edge of the heart, continues to run in the coronary groove on the diaphragmatic surface, and gives off the posterior descending branch, i.e., the posterior interventricular branch, near the atrioventricular node.

The right coronary artery gives rise to:

(1) Conus arteriosus branches are distributed in the conus arteriosus and anastomose with the branches of the same name of the left coronary artery.

(2) Right marginal branch: This branch is relatively large and runs to the left along the inferior cardiac margin toward the apex of the heart.

(3) sinoatrial node branches, which branch off from the main trunk near the origin (accounting for 60.9%, and the remaining 39.1% originate from the left coronary artery);

(4) Atrioventricular nodal branch: It originates from the right coronary artery and runs deep to the atrioventricular node.

(5) The posterior interventricular branch is the terminal branch of the right coronary artery. It anastomoses with the anterior interventricular branch of the left coronary artery and branches to the posterior wall of the left and right ventricles, and to the posterior 1/3 of the ventricular septum.

Blood supply relationship:

Based on the direction and distribution of coronary artery branches, it is not difficult to infer where they nourish the heart.

1. Right atrium and right ventricle: supplied by the right coronary artery.

2. Left ventricle: 50% of its blood supply comes from the left anterior descending artery, mainly supplying the anterior wall and ventricular septum of the left ventricle; 30% comes from the circumflex artery, mainly supplying the lateral wall and posterior wall of the left ventricle; and 20% comes from the right coronary artery (right dominant type), supplying the inferior wall (diaphragmatic surface), posterior wall and ventricular septum of the left ventricle. However, in the left-dominant type, these areas are supplied by the left circumflex coronary artery, while in the balanced type, both the left and right coronary arteries supply blood.

3. Ventricular septum: The upper 2/3 is supplied by the anterior descending branch, and the lower 1/3 is supplied by the posterior descending branch.

4. Conduction system: 60% of the blood of the sinoatrial node is supplied by the right coronary artery, and 40% by the left circumflex branch; 90% of the blood of the atrioventricular node is supplied by the right coronary artery, and 10% by the left circumflex branch; the right bundle branch and the left anterior branch are supplied by the anterior descending branch, and the left posterior branch is supplied by both the left circumflex branch and the right coronary artery. Therefore, conduction block of the left posterior branch is rare in clinical practice. The left bundle branch is supplied by multiple sources including the anterior descending artery and the right coronary artery.