Coronary Arteries – Anatomy
1. The left coronary artery
Anterior descending artery;
Sometimes the trunk of the left coronary artery divides into three branches: the left anterior descending artery, circumflex artery and an intermediate ram.
This one goes through the anterior interventricular groove to the apex and is surrounding it and continues with 1-2 cm in the posterior interventricular groove (recurrent artery).
It gives the following branches:
Diagonal arteries: irrigate the anterior wall of the left ventricle and a part of the antero-lateral papillary muscle;
anterior septal arteries: irrigate two-thirds of anterior interventricular septum, the right and left branch of the His bundle;
Posterior septal branches (from recurrent artery): irrigates one-third of the posterior interventricular septum;
Anterior right ventricular branches (left artery of the pulmonary cone).
Left anterior descending artery (LAD) is divided into three segments:
First Segment (proximal): between the left coronary artery trunk and the first diagonal (when this is missing until the first septal).
Second Segment (medium): between the first and the second diagonal.
Third Segment (distal): after the second diagonal artery.
It surrounds the heart through the left segment of the coronary groove, ends variable to the left or right of the “crux cordis”, often after giving 2-3 branches to the lateral wall of the left ventricle (marginal artery) and posterior-lateral branches to the posterior wall of left ventricle or descends through posterior interventricular groove giving the posterior descending artery (left dominant or codominant).
Branches for left ventricle wall (obtuse marginal I, obtuse marginal II);
The artery of the left atrium with the sinus node artery (45%);
The posterior descending artery and the lateral-posterior (15% of cases).
It is divided into two segments:
Proximal segment (from the origin to the emergence of obtuse Marginal I);
Distal segment (from emergence of obtuse Marginal I).
It irrigates the sidewall and posterior wall of the left ventricle, and a part of the anterolateral papillary muscle.
2. Right coronary artery
It has the origin in the right coronary sinus and traverses the right half of the coronal groove. Overall trajectory of the right coronary artery is generally a symmetrical path against the side of the circumflex artery together making a front circle. In the type of right dominant coronary system, at the level of “crux cordis”, the right coronary artery continues with posterior descending artery and lateral-posterior system.
Collateral branches are:
The artery-cone (participates at the Vieussens ring along with the right ventricular branches from the left anterior descending artery) (20-30% of the cases have a separate origin, directly from the aorta);
Atrial sinus node (55%);
Right marginal artery (irritates the right ventricle and apex);
Atrioventricular node artery (irrigates the AV node);
Posterior descending artery (irrigates one-third of the posterior interventricular septum);
The posterior-lateral system.
In the right dominant system the right coronary artery irrigates: the inferior wall of the left ventricle, the inferior ventricular septum, atrioventricular node, right ramus and the posterior portion of the left ramus of the His bundle, the posterior medial papillary muscle.
The right coronary artery is angiographically divided into three segments:
First Segment (from the origin to the first curve);
Second Segment (first curvature to a second curvature);
Third Segment (from the second curve to the crux cordis).
The notion of dominance
The artery that supply with blood the lower face of the heart is called the “dominant” and is represented by the posterior descending artery and posterior-lateral system. This vessels are branches of the right coronary artery (85% of the cases) or circumflex artery (8% of the cases ).
Balanced coronary system (7% of the cases): posterior descending artery is given by the right coronary artery and the posterior-lateral system by the circumflex artery.