Generality
The coronary arteries are the two arteries of the human body, which have the important task of oxygenating the muscle tissue of the heart, in order to keep the latter healthy and indirectly optimize its functionality.
The two coronaries arise from the ascending aorta - to be precise in a section called the aortic root - and one is distributed on the right side of the heart (right coronary artery) and one on the left portion of the heart (left coronary artery).
The coronaries are able to reach every district of the muscle tissue of the heart, as they are endowed with numerous branches, which take the generic name of branches.
If the object of narrowing or occlusion is present, the coronary arteries are responsible for a medical condition known as coronary artery disease; the phenomenon of coronary heart disease sets the stage for a very feared pathology: myocardial ischemia.
What are Coronaries?
The coronaries, or coronary arteries, are the arterial vessels which, with the help of their numerous branches, extend over the entire external surface of the heart and provide to supply the myocardium, that is the heart muscle, with oxygenated blood.
The coronaries, therefore, are the arteries that keep the heart, that is the organ on which the well-being of the whole organism depends, alive, healthy and in function.
When the heart does not receive the right amount of blood, it begins to suffer - because it lacks the oxygen that keeps it alive - and works badly.
The suffering and malfunctioning of the heart affects the well-being and functional capacity of all the other organs of the human body, brain in the first place.
Anatomy
The coronary arteries are two and they originate at the beginning of the aorta, the large arterial vessel of the human body that is born from the left ventricle of the heart.
The coronaries are distributed one on the left side and one on the right side of the heart, in order to exhaustively supply all the tissues of this organ so important for life; the coronary that feeds the left sector of the heart is called the left coronary artery (or left coronary artery ), while the coronary artery that nourishes the right sector of the heart is indicated by the name of right coronary artery (or right coronary artery ).
In moving away from the aorta and spreading over the heart muscle, both coronaries are divided into various branches, called branches, which are fundamental for highly efficient blood circulation.
Did you know that ...
The coronaries hold the title of " first branches of the aorta "; before them, in fact, the aorta does not give birth to other secondary blood vessels.
Origin of the Coronary: the details
The coronaries are born in correspondence of the first line of the ascending aorta, a tract that is known as aortic root and that presents 3 characteristic inlets known as aortic sinuses .
"Ascending aorta" is the anatomical name of the first portion of the aorta, a portion that begins immediately after the aortic valve, present on the left ventricle of the heart, and that ends with the beginning of the aortic arch.
More specifically, the left coronary arises from the so-called anterior aortic sinus of the aortic root, while the right coronary arises from the so-called left posterior aortic sinus of the aortic root.
The aortic root can be defined as the short segment of ascending aorta, which goes from the so-called aortic anulus (fibrous ring that surrounds the aortic valve orifice) to the so-called sino-tubular junction (border region that marks the end of each relationship between the 'ascending aorta and aortic valve).
Course of the Coronary: the details
CORONARIA RIGHT AND ITS BRANCHE
From the posterior aortic sinus, the right coronary arises towards the right section of the heart and, with a lower-diagonal orientation, take and pass through the so-called right coronary sulcus, until it reaches the crux cordis .
The right coronary sulcus is the groove visible on the outside of the heart, which marks the internal separation between the right atrium and the right ventricle.
The crux cordis, on the other hand, is the cruciform groove that forms on the lower part of the posterior side from the heart, due to the encounter between the coronary grooves (line of separation between an atrium and its underlying ventricle) and the interventricular septum (lamina of cardiac tissue that separates the two ventricles).
In following the aforementioned path (right coronary sulcus - crux cordis ), the right coronary emits 3 collateral branches, which, specifically, are:
- The right posterior descending artery (or posterior interventricular artery ). Equipped with small sub-branches, this branch of the right coronary arises in the posterior part of the right ventricle.
- The right marginal artery . This branch of the right coronary arises along the anterior surface of the right ventricle.
- The artery of the sino-atrial node and the atrio-ventricular node . This branch of the right coronary arises where the heart has its electrical conduction system, ie the set of components that controls the heartbeat. It should be noted that the artery of the sino-atrial node and of the atrio-ventricular node is, in 60% of the people, a branch of the right coronary artery and, in the remaining 40% of individuals, a sub-branch of the left coronary artery branch as a left circumflex artery.
Please note
The branches of an artery are its branches. Therefore, they are blood vessels with the same characteristics - except the caliber that is smaller - and can be called arteries, without making mistakes in terminology.
CORONARIA LEFT AND ITS BRANCHE
Starting from the anterior aortic sinus, the left coronary artery moves towards the left section of the heart and, with a lower-diagonal orientation, wedges itself in the left coronary sulcus for about 20 millimeters; after which, it stops its course, dividing into two branches, which are:
- The left anterior descending artery (or anterior interventricular artery ). This terminal branch of the left coronary arises in the anterior portion of the left side of the heart.
The left anterior descending artery includes several sub- branches, whose names are: diagonal arteries (or diagonal branches ) and septal arteries (or septal branches ).
- The left circumflex artery . This terminal branch of the left coronary is the protagonist of a long course, which starts from the left side to the heart and ends behind the left ventricle.
Like the previous branch, the left circumflex artery also includes several sub-branches, which are: the left atrial artery (or left atrial branch), the left marginal artery (or left marginal branch) and, in 40% of people, l artery of the sinoatrial node and of the atrio-ventricular node (remember that, in 60% of individuals, this arterial vessel is a branch of the left coronary artery).
Other characteristics of the Coronary: Anastomoses
To understand: what is an anastomosis?
In anatomy, the term " anastomosis " generally indicates a connection between blood vessels, which, in the case of the arteries, has the purpose of guaranteeing an effective blood supply upon occurrence of a vessel obstruction / occlusion.
The coronary arteries have anastomoses, which, unlike similar structures present in other parts of the human body (eg: palm), are not very efficient in guaranteeing a continuous blood supply in case of vessel obstructions.
Specifically, the most important coronary anastomoses are:
- The anastomosis located at the level of the interventricular sulcus (line that separates into two ventricles) between the sub-arches of the left anterior descending artery (branch of the left coronary artery) and the branches of the right posterior descending artery
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- The anastomosis located at the level of the atrio-ventricular groove between the left circumflex artery (left coronary artery branch) and the right coronary artery.
variants
In some people, the coronary arteries have an anatomy different from the one reported above.
In fact, it can happen that
- The right posterior descending artery, instead of being a branch of the right coronary artery, is a sub-branch of the left circumflex artery (terminal branch of the left coronary artery) or at the same time a branching of the right coronary artery and the left circumflex artery;
- The coronaries, instead of being 2, are 3. In this case, the third coronary is called the posterior coronary artery ;
- One of the two coronaries, instead of being a single vessel, is a double vessel, in which the two vascular structures run parallel;
- The artery of the sino-atrial node and of the atrio-ventricular node, rather than being a branch of the right coronary artery, is a branch of the left circumflex artery (hence, in fact, indirectly a branch of the left coronary artery).
Deepening: concept of dominance of the coronary circulation
The anatomy of the right posterior descending artery determines the dominance of blood circulation along the coronary arteries. In fact, if this branch belongs to the right coronary artery, we speak of coronary circulation with right dominance ; if it derives from the left circumflex artery, we speak of coronary circulation with left dominance ; finally, if it descends both from the right coronary artery and from the left circumflex artery, we speak of coronary circulation with common dominance (or double dominance).
According to reliable research, 70% of the population would present coronary circulation with right dominance (this is not surprising, given that it coincides with the normal anatomy of the coronaries described in the previous lines), 20% common coronary circulation and the remaining 10 % the coronary circulation with left dominance.
Function
The coronary arteries have the task of supplying the muscle tissue of the walls of the heart with oxygenated blood as well as the papillary muscles of the atrioventricular valves ( tricuspid valve, between the right atrium and right ventricle, and mitral valve, between the left atrium and the left ventricle).
More specific, the right coronary feeds:
- The right atrium ;
- The right ventricle and 25-35% of the left ventricle . The blood circulation of these areas of the heart belongs to the right posterior descending artery branches and the right marginal artery;
- In 60% of people, the electrical conduction system . The supply of oxygenated blood to this cardiac area rests with the artery of the sino-atrial node and of the atrio-ventricular node;
- The posterolateral papillary muscle of the atrioventricular valves. Sprayed with blood, this muscle is the right posterior descending artery.
The left coronary, on the other hand, nourishes:
- The left atrium, with the left anterior descending artery;
- The part of the left ventricle not fed by the branches of the right coronary artery, with the left anterior descending artery (between 45-55% of the surface) and the left circumflex artery (remaining surface);
- The interventricular septum, with the left anterior descending artery;
- The antero-lateral papillary muscle of the atrioventricular valves, with the left circumflex artery;
- In 40% of the population, the electrical conduction system of the heart, with a branch of the left circumflex artery.
The blood supply guaranteed by the coronary arteries in the heart is fundamental for the survival of the organism: a heart that receives the right supply of oxygenated blood is healthy and adequately carries out its function as a blood pump, a function that serves to supply oxygen to all other body organs.
diseases
Coronary arteries are at the center of a very known and widespread pathology, which is called coronary artery disease or coronary artery disease .
What is Coronary Artery Disease?
In coronary artery disease, it happens that one of the coronaries is the victim of a narrowing or an obstruction, such that the flow of blood through it is reduced or absent and the muscle tissue of the heart receives less oxygen than would be necessary. In other words, in those suffering from coronary artery disease, the blood circulation inside the coronary arteries is less efficient, due to an impediment inside one of the aforementioned arteries, and the oxygen supply to the myocardium is lower than required.
In light of this and of what has been said about the importance of optimal blood circulation in the coronaries for heart health, the phenomenon of coronary heart disease inevitably triggers a state of suffering of the cardiac organ as well as a reduction in its functional efficiency .
CONSEQUENCE OF CORONAROPATHY: ISCHEMIA OF MYCHARDIUM
The narrowing or occlusion of a coronary artery and the consequent reduced myocardial oxygen supply lay the foundation for a medical condition known as myocardial ischemia or ischemic heart disease .
Doctors talk about myocardial ischemia, when the muscle tissue of the heart receives, due to a narrowing or occlusion of the coronaries, a quantity of oxygen lower than the real needs.
Myocardial ischemia can be transient or permanent, depending on whether the impediment inside the coronaries is something passing or not.
When it is transient, myocardial ischemia is an example of angina pectoris ; when it is permanent, it is an example of a very feared and sadly famous condition, called myocardial infarction or heart attack .
Did you know that ...
According to reliable epidemiological studies, myocardial ischemia would represent the main cause of death in Western world countries .
Causes of coronary artery disease
In most cases, coronary heart disease is associated with atherosclerosis and the thrombo-embolic effects that this condition can have at the coronary level; more rarely, it depends on episodes of coronary vasculitis (inflammation of the walls of the coronary arteries) or of coronary spasm (sudden narrowing of the coronary arteries due to a sudden contraction of the vascular wall).
