The main arteries of the heart. Anatomy of the coronary arteries: functions, structure and mechanism of blood supply

In embryos at an early stage of development, the walls of the heart are formed by loosely arranged muscle fibers, which are supplied with blood from the chambers, like the spongy subendocardium in adult frogs. As the embryo grows, the walls of the heart thicken and the muscle layers are more compact. To supply metabolically active myocardium with substrates, intramural coronary arteries, capillaries and veins are formed from intramuscular sinusoids. Sinusoids form connections with the coronary sinus. Shortly thereafter, around day 44 of gestation, extramural vessels begin to develop from the base of the aorta and protrude toward the apex of the heart. They develop penetrating branches that enter the myocardium and connect to the primitive sinusoidal system. The same rudiments are laid at the base of the pulmonary artery.

Additional coronary arteries

These coronary arteries are typical branches of the coronary arteries, arising as an independent mouth from the sinuses of Valsalva, so only their mouth is additional. The most common pathology is the right coronary artery. The presence of 2 to 5 additional orifices in the right coronary sinus has been described. Its first branch, the conus artery, arises as an independent artery from the right sinus of Valsalva in 50% of patients. In this case, it is called the right accessory coronary artery.

1% healthy people and more often with bicuspid aortic valve the anterior descending artery and the circumflex branch of the left coronary artery arise as independent orifices from the left sinus. The anterior descending artery can arise as an independent orifice from the right sinus. The first branch of the penetrating coronary artery may arise from the left coronary sinus as a separate orifice.

None of these variants of coronary artery anatomy have clinical consequences and is not included in the list of coronary artery anomalies.

Stenosis and atresia of the coronary artery ostium

This rare congenital anomaly most often affects the left coronary artery. It may be the result of:

intrauterine inflammation;

fibromuscular dysplasia;

congenital malformation.

The absence of the extramural part of the coronary artery is more often observed in pulmonary atresia with an intact interventricular septum and in aortic atresia. The pressure in small and sharply hypertrophied right or left ventricles exceeds the pressure in the aorta. Coronary circulation is carried out through dilated sinusoids connected to the coronary arteries. El-Said et al described atresia of the left coronary artery ostium in a 14-year-old boy who complained of cardiac pain, fatigue on exertion, and syncope. He had a systolic murmur at the apex; ventricular extrasystoles were periodically recorded on the ECG; bicycle ergometry revealed a shift of the ST segment below the isoline by 3 mm. Coronary angiography revealed retrograde filling of the left coronary artery through collaterals. The authors completed coronary artery bypass surgery using v. saphena. Similarities clinical symptoms and ECG data in such patients with endocardial fibroelastosis is a reason to diagnose isolated fibroelastosis or anomalous origin of the left coronary artery from pulmonary trunk. Molander described the case history of a 19-year-old boy who had been under observation for mitral valve insufficiency since the age of 4. Catheterization did not shed light on the etiology of the disease. The patient died suddenly. Autopsy revealed old and recent myocardial infarction and severe stenosis of the left coronary artery.

Tangential origin of the coronary arteries from the aorta

Normally, the coronary arteries arise from the aorta at right angles. Whitat et al analyzed 22 cases sudden death adults. In 10 of them, the right coronary artery and in 3, both coronary arteries departed from the aorta tangentially, at an angle of less than 450 between the coronary artery and the aortic wall. The mouth of the affected artery was in the form of a slit, and in 9 people the mouth was partially covered by a protruding ridge like a valve. Other reports of ischemia or death from intramural origin of the coronary arteries suggest that this anomaly is not uncommon. Sudden deaths have been described in adults, but there is a report of a 5-month-old infant dying from this cause

If this anomaly is detected by echocardiography or coronary artery disease, surgical intervention must be undertaken.

Anomalous coronary artery path between the aorta and pulmonary artery

One of the coronary arteries may pass between the aorta and the pulmonary trunk with its normal origin from various sinuses. An unnatural path of the artery also occurs with various options for the origin of the coronary arteries:

the only coronary artery arising from the right aortic sinus, and the left main coronary artery or anterior descending artery passing between main arteries;

the only coronary artery arising from the left aortic sinus and the right coronary artery passing between the great arteries.

When the orifices of both coronary arteries are in the same sinus, the orifice of the anomalous artery may have a slit-like appearance.

The artery passing between the aorta and the pulmonary trunk can be pinched by the myocardium, especially during exercise, and cause sudden death. Patients often have no symptoms until they faint. Frequency and natural history The abnormal location of the coronary arteries between the great vessels has not been studied. All patients with anginal pain and fainting states Coronary angiography is indicated and, if this pathology is detected, surgical intervention is indicated.

If there are two orifices in one sinus, surgery involves widening and remodeling the anomalous orifice to relieve compression between the main arteries. In this case, bypass surgery may be ineffective due to competing blood flow from the aorta and decreased blood flow through the anastomosis with subsequent thrombosis. However, when there is a single coronary artery and the left main or right coronary artery passes between major vessels, relief of the obstruction by reimplantation or ostial remodeling may not be possible, so bypass grafting becomes the only choice.

Operation technique

After studying the anatomy and starting artificial circulation, the aorta is clamped, the heart is relaxed, and the aorta is opened with a transverse incision. The mouth of the anomalous coronary artery is slit-like and narrow. Since the orifice may be located in close proximity to the commissure, it is necessary to separate it from the aortic wall. The ostium is cut along the long axis of the coronary artery and part of the common wall between the aorta and the artery is dissected. The artery is anastomosed with the aorta with 7/0 or 8/0 prolene. The aortic valve commissure is secured in place with a padded suture. The aortic incision is sutured, the clamp is removed from the aorta after removing air from the cavities of the heart. The operation is completed in the standard way.

Anomalous origin of the left coronary artery and its branches from the right sinus of Valsalva

Among all the anomalies of the coronary arteries, the most common is the origin of the left circumflex coronary artery from the right coronary artery. The circumflex artery passes behind the aorta and reaches its normal blood supply. This anomaly has no clinical significance, however, it can be compressed during double mitral and aortic valve replacement. This artery is characterized high probability lesions from atherosclerotic plaques.

Much less common among coronary artery anomalies is the origin of the left main coronary artery from the right sinus of Valsalva. There are 4 possible options for the passage of this artery:

behind the aorta;

in front of the outflow tract of the right ventricle;

in the thickness of the interventricular septum below the conical part of the right ventricle;

between the aorta and the outflow tract of the right ventricle.

With the exception of the two described cases, the first three routes are not accompanied by sudden death or premature myocardial ischemia. The passage of a coronary artery between two great arteries often leads to sudden death in childhood and in adults during or immediately after heavy exercise, since under these conditions the increase in pressure in the aorta and pulmonary artery increases compression of the left coronary artery until it occludes. Preceding symptoms are dizziness and heart pain during exercise. At autopsy, in most cases, a slit-like mouth of the left main coronary artery was found, arising from the aorta at an acute angle and accreting to the aortic wall for about 1.5 cm.

In some patients, the anterior descending coronary artery arises from the right coronary sinus of Valsalva or from the right main coronary artery. This anomaly is rare in the absence of congenital heart disease, but is quite common in tetralogy of Fallot. The artery usually passes along the anterior surface of the outflow tract of the right ventricle or in the thickness of the interventricular septum and rarely between the aorta and the outflow tract of the right ventricle. Sometimes near the mouth common artery An atheromatous plaque is located, so most of the heart is in a state of ischemia, as in stenosis of the main left coronary artery.

Origin of the right coronary artery or its branches from the left sinus of Valsalva

The origin of the right main coronary artery from the left sinus of Valsalva accounts for 30% of all coronary artery anomalies. The artery follows between the aorta and the outflow tract of the right ventricle, then passes through the atrioventricular groove and branches normally. This option is considered relatively benign, but there are many reports of myocardial ischemia, infarction, and sudden death. IN clinical picture Predominant pain in the heart, arrhythmia at rest or during physical activity. During postmortem examinations, the right coronary artery often emerged at an angle to the aorta, and the orifice had a slit-like shape.

Anomalies of coronary vessels accompanying congenital heart disease

With various heart defects, a certain set of anomalies of the coronary arteries sometimes occurs. Below is brief description this pathology.

Tetralogy of Fallot

About 40% of patients have an unusually long, large conus artery, which supplies a significant mass of myocardium. In 4-5% of cases, the anterior interventricular branch arises from the right coronary artery and crosses the outflow tract of the right ventricle. Sometimes there is a single coronary artery arising from the right or left sinus. Its large branches may cross the anterior surface of the right ventricle or pass behind the aorta outside the area of ​​the ventricular outflow tract. Other, rare branching options are also possible. The left main coronary artery occasionally passes in front of the pulmonary artery.

If a large artery crosses the right ventricular outflow tract, correction of the defect becomes more difficult. To prevent the intersection of an artery and a heart attack in the area of ​​its blood supply, surgeons use various techniques:

a section of the right ventricle parallel to the course of the artery;

incisions above and below the artery;

creating a tunnel under the artery;

bypassing the narrowed area with an external conduit.

The use of these methods does not guarantee the creation of a free exit in pulmonary artery. In young children, unfavorable coronary artery anatomy may influence the choice of palliative surgery.

Anomalous passage of the coronary arteries may be suspected by echocardiography and angiography of the aortic root. Although the surgeon sees the coronary arteries during surgery, it is important to establish an accurate diagnosis before surgery to eliminate surprise and plan adequate surgery in advance. In addition, if the patient has epicardial adhesions from a previous operation or if the artery runs deep into the myocardium, it cannot be seen during surgery, so it can be divided with serious consequences. In this regard, all patients who have previously undergone intrapericardial interventions should undergo aortic root angiography. In practice, there have been episodes of crossing a significant coronary artery that required bypass surgery with the internal mammary artery.

Full TMA

With this defect, the mutual orientation of the aorta and the main pulmonary artery differs from the norm, and the aortic sinuses are also located unusually. The left sinus facing the pulmonary artery is called the left presenting sinus, even if it is anterior, and the right sinus is called the right presenting sinus, even if it is posterior.

The coronary arteries arise predominantly from the adjacent sinuses. In 60% of cases, they arise from their own sinuses and branch normally when the aorta is located in front and slightly to the right of the pulmonary artery. But since the aorta is located anteriorly, the left main and circumflex arteries pass in front of the outflow tract of the right ventricle.

In 60% of patients, the right coronary artery arises from the posterior sinus; in 20%, the right coronary artery arises from the posterior sinus with simultaneous independent origin of the anterior descending branch from the left sinus. Other anatomical variants are less common. In 8% of cases, a single coronary artery is observed, which arises from the right adjacent sinus and then follows posteriorly to the pulmonary trunk, or arises from the left adjacent sinus and goes anteriorly to the outflow tract of the right ventricle. In 5% of cases, both main arteries arise from the same adjacent sinus, usually the right one, and one or both arteries run intramural, giving the appearance of arising from different sinuses. There may be other rare variants.

Coronary artery variations influence the planning and performance of arterial switch surgery, as it may be difficult to move the coronary artery ostia into the neoaorta without tension. To solve these problems, various techniques for tunneling the coronary arteries have been developed.

Corrected TMA

The aorta is located anterior and to the left of the pulmonary trunk and both main coronary arteries originate from the adjacent sinuses. The anterior sinus is usually non-coronary. Due to the peculiarities of anatomy, there is confusion regarding the name of coronary arteries that do not arise from their sinuses. Some authors describe the coronary vessels as right- or left-sided, according to the sinuses from which they arise. Others describe arteries by the territory they supply. This is the terminology used here.

The left coronary artery supplies the anatomically left ventricle, however, it arises from the right adjacent sinus. It passes in front of the pulmonary artery and divides into the left anterior descending and circumflex branches. The latter passes in front of the right atrial appendage in the atrioventricular groove.

The right coronary artery supplies the right ventricle. It originates from the left accumbens sinus and passes in the atrioventricular groove anterior to the left atrial appendage, continuing as the posterior descending artery. The most common variant is a single coronary artery arising from the right adjacent sinus.

Dual-flow left ventricle

With this defect, there is no true interventricular septum and a typical interventricular groove. The branches of the coronary arteries that run along the edges of the rudimentary exit chamber are delimiting rather than the anterior descending arteries that normally supply the anterior part of the interventricular septum.

When the outlet chamber is located anteriorly and to the right, the relative position of the aorta and pulmonary trunk is the same as when full transposition. The right coronary artery arises from the right adjacent aortic sinus and courses in the right atrioventricular groove. The left main coronary artery originates from the left accumbens sinus and follows as the circumflex artery in the left atrioventricular groove. The left and right delimiting arteries depart from the left and right coronary arteries, respectively.

When the outlet chamber is located at the front and left, the orientation large vessels the same as with corrected transposition. The right and left main coronary arteries arise from their own adjacent sinuses, and the anterior descending coronary artery may arise from the left or right coronary arteries or there may be two delimiting arteries that limit the vestigial outlet chamber. With any of these options, there may be several large diagonal arterial branches that run parallel to the delimiting branches and cross the right ventricular outflow tract, making fixation of the artificial interventricular septum difficult.

Right ventricle with two outlets

In most forms of this group of anomalies, the coronary arteries usually arise normally, except that due to clockwise rotation of the aortic sinuses, the right coronary artery arises anteriorly and the left coronary artery arises posteriorly. When the aorta is located anteriorly and to the right, the anatomy of the coronary arteries is the same as with complete transposition, i.e. the right coronary artery arises from the right adjacent sinus. In 15% of cases there may be a single coronary artery arising anteriorly or posteriorly. Sometimes the left anterior descending artery arises from the right coronary artery and crosses the outflow tract of the right ventricle, as in tetralogy of Fallot. When the aorta is located on the left, the right coronary artery courses to the right from the anterior sinus of the aorta in front of the pulmonary artery until it reaches the atrioventricular groove.

Common truncus arteriosus

The right and left coronary arteries arise normally from their sinuses. If the valve has more than three leaflets, the usual description must be abandoned. The most constant is the origin of the left main coronary artery from the posterior sinus. From a surgical point of view, options such as an unusually high and close location of the orifices or a single orifice are important. Large diagonal branches The right coronary artery can cross the anterior surface of the right ventricle and supply blood to the interventricular septum, and even part of the free wall of the left ventricle. Crossing these arteries can lead to severe myocardial damage, heart failure, and death.

Single coronary artery

A single coronary artery was first described by Tebesi in 1716; its next description was presented by Hyrtl in 1841. As an isolated defect, this anomaly is extremely rare - 1 case in 2000-7000 of all coronary angiographies performed, somewhat more often among males. Smith proposed the following classification of this anomaly:

A single coronary artery that is a variant of the normal left or right coronary artery.

The only coronary artery from which the normal left and right arteries arise.

A single coronary artery with a circumflex arrangement that differs from its normal location.

The trunk of a single coronary artery or its main branch can be located behind the aorta, between it and the pulmonary trunk, or pass in front of the trunk of the pulmonary artery. In the latter case, the anomaly is particularly dangerous, especially with tetralogy of Fallot or other defects accompanied by narrowing of the outflow tract of the right ventricle, requiring its plasty. Anomalies of the right coronary artery are more common than the left. An isolated defect in the form of a single coronary artery can sometimes be the cause of sudden death, ischemia or myocardial infarction, especially when the left or right artery departs from a common trunk or they pass together between the aorta and the trunk of the pulmonary artery.

A single coronary artery may be present with a bicuspid aortic valve or accompany complex heart defects. It most often occurs in tetralogy of Fallot, tetralogy of Fallot with pulmonary atresia, TMA, right ventricle with two outlets, left ventricle with two outlets, common truncus arteriosus, single/common ventricle, ASD with pulmonary artery stenosis, heterotaxy.

Quite often, a single coronary artery is found in patients with tetralogy of Fallot. It occurs in 5% of children with TMA; in this case, the artery arises from the posterior sinus and divides into two normal coronary arteries: the right and left.

The most favorable anomaly of the coronary arteries is the origin of both arteries by separate or common ostia from one sinus of Valsalva. A normal origin of one coronary artery from the aorta with a branch of the left coronary artery from it was also noted. Complete absence one of the coronary arteries is an extremely rare anomaly. In this case, the existing coronary artery independently provides coronary circulation. There are many reports in the literature of cases of a single coronary artery, usually concomitant with other congenital heart pathologies, as well as cases of a single coronary artery with normal cardiac morphology.

Intramural passage of the coronary artery

In some cases, the initial section of the left coronary artery, arising from the right aortic sinus, is located in the thickness of the aortic wall. On histological examination, the vessels have a single middle membrane; it is common to the aorta and coronary artery. This anatomical location of the coronary artery is sometimes the cause of sudden death. When the ascending aorta, rich in fibrous fibers, expands during systole, compression of the intramural segment of the left coronary artery occurs, which leads to myocardial ischemia. Treatment of this syndrome consists of surgical plastic surgery of the coronary artery with isolation of this segment from the aortic wall or the application of a shunt bypassing the intramural segment.

The intramural location of the coronary artery in a child with TMA requires a more complex surgical technique when performing anatomical correction of this defect.

"Diving Arteries"

The large epicardial coronary arteries normally run along the surface and only terminal branches penetrate into the thickness of the myocardium. In 50% of people, the coronary arteries are sometimes buried in the thickness of the myocardium, and then reappear on its surface. In these cases, a muscular bridge is formed over a large coronary artery. Most often, the “mural” is the left anterior descending branch in its proximal half. This anomaly is found in both infants and older people. At the age of up to 20 years, the length of the submerged part is on average 14 mm, at an older age - 20-30 mm. In approximately 75% of cases, the anterior descending coronary artery passes in the interventricular groove and may be covered by several superficial bridges of muscle fibers; in 25%, the anterior interventricular artery deviates towards the right ventricle and passes deep into the interventricular septum, where it is crossed by a muscle bundle emanating from apex of the right ventricle.

Most muscle bridges do not have functional significance, especially if they lie superficially. However, cases have been described when, during physical activity, the submerged part of the coronary artery narrows, which becomes the cause of acute coronary insufficiency and sudden death, including in patients after myotomy.

During coronary angiography, it is clear that part of the coronary artery is narrowed in systole, but is well passable in diastole. In the presence of pain, careful release of the coronary artery from the muscle tunnel is indicated. Surgery is indicated if there is objective evidence of ischemia on the electrocardiogram and increased lactate production in the regional vein. Ischemia usually occurs when there is a long, thick muscle bridge that compresses the artery and relaxes unusually slowly so that diastolic filling of the distal coronary artery is impaired. After performing a thorough myotomy pain syndrome and signs of ischemia disappear.

In children, diving coronary arteries are rare and occur only in cases of ventricular hypertrophy, especially hypertrophic cardiomyopathy.

Coronary artery aneurysm

It was first described in 1812. It is an extremely rare anomaly. Only one in five coronary artery aneurysms are congenital. Acquired aneurysm can occur in children as a result of Kawasaki disease, endocarditis, nodular coronaritis, and in adults as a result of the development of atherosclerosis, syphilitic lesions of the coronary arteries, or against the background of a congenital fistula of the coronary artery. A coronary artery aneurysm can also form as a result of myocardial infarction. Congenital aneurysm occurs due to a disturbance in the structure of the vascular mesothelium or a deficiency of normal protein fibers of the connective tissue. Aneurysmal dilatation can affect both the right and left coronary artery; in very rare cases, both arteries can be affected, and even more rarely, multiple aneurysms of the coronary arteries are diagnosed. Described combined defect in the form of TMA with coronary artery aneurysm. All types of coronary artery aneurysms can either be asymptomatic until they rupture, or lead to the development of ischemia or myocardial infarction. Cases of thrombosis of a coronary artery aneurysm have been described.

Surgical treatment

Indications for surgery are signs of myocardial ischemia or accidental discovery of an aneurysm. large sizes. The operation consists of resection of the aneurysm and the application of a coronary artery bypass graft, or ligation of the aneurysm at its initial and final sections with the application of a coronary artery bypass graft below the aneurysm. Indications for surgical intervention may arise for both congenital and acquired coronary artery aneurysm. An aneurysm resulting from Kawasaki disease rarely requires surgical intervention, except in cases of threat of aneurysm rupture or thrombosis.

The type of blood supply to the heart refers to the predominant distribution of the right and left coronary arteries on the posterior surface of the heart.

The anatomical criterion for assessing the predominant type of distribution of the coronary arteries is the avascular zone on the posterior surface of the heart, formed by the intersection of the coronary and interventricular grooves - crux. Depending on which of the arteries - right or left - reaches this zone, the predominant right or left type of blood supply to the heart is distinguished. The artery reaching this zone always gives off the posterior interventricular branch, which runs along the posterior interventricular groove towards the apex of the heart and supplies the posterior part of the interventricular septum. Another anatomical sign is described to determine the predominant type of blood supply. It has been noted that the branch to the atrioventricular node always arises from the predominant artery, i.e. from an artery that has highest value in feeding blood to the posterior surface of the heart.

Thus, with predominant right type of blood supply to the heart The right coronary artery supplies the right atrium, right ventricle, posterior part of the interventricular septum, and posterior surface of the left ventricle. The right coronary artery is represented by a large trunk, and the left circumflex artery is poorly expressed.

With predominant left type of blood supply to the heart the right coronary artery is narrow and ends in short branches on the phrenic surface of the right ventricle, and the posterior surface of the left ventricle, rear end The interventricular septum, the atrioventricular node and most of the posterior surface of the ventricle receive blood from the well-defined large left circumflex artery.

In addition, there are also balanced type of blood supply, in which the right and left coronary arteries make approximately equal contributions to the blood supply to the posterior surface of the heart.

The concept of “predominant type of blood supply to the heart,” although conditional, is based on anatomical structure and distribution of coronary arteries in the heart. Since the mass of the left ventricle is significantly greater than the right, and the left coronary artery always supplies most of the left ventricle, 2/3 of the interventricular septum and the wall of the right ventricle, it is clear that the left coronary artery is the predominant one in all normal hearts. Thus, with any type of coronary blood supply, the left coronary artery is predominant in a physiological sense.

Nevertheless, the concept of “predominant type of blood supply to the heart” is valid, is used to assess anatomical findings during coronary angiography and has a large practical significance when determining indications for myocardial revascularization.

For topical indication of lesion sites, it is proposed to divide the coronary bed into segments

The dotted lines in this diagram highlight the segments of the coronary arteries.

Thus in the left coronary artery in the front interventricular branch it is divided into three segments:

1. proximal - from the place of origin of the LAD from the trunk to the first septal perforator or 1DV.
2. average – from 1DV to 2DV.
3. distal – after departure of the 2DV.

In the circumflex artery It is also customary to distinguish three segments:

1. proximal - from the mouth of the OB to 1 VTK.
2. average - from 1 VTK to 3 VTK.
3. distal - after separation of the 3rd VTC.

Right coronary artery is divided into the following main segments:

1. proximal – from the mouth to 1 VOK
2. medium – from 1 VOC to the acute edge of the heart
3. distal – before the bifurcation of the RCA into the posterior descending and posterolateral arteries.

Coronary arteries of the heart

In this section you will become familiar with the anatomical location of the coronary vessels of the heart. To become familiar with the anatomy and physiology of the heart vascular system You need to visit the “Heart Diseases” section.

• Left coronary artery.
• Right coronary artery

The blood supply to the heart is carried out through two main vessels - the right and left coronary arteries, starting from the aorta immediately above the semilunar valves.

Left coronary artery.

The left coronary artery begins from the left posterior sinus of Vilsalva, goes down to the anterior longitudinal groove, leaving the pulmonary artery to the right, and to the left the left atrium and the appendage surrounded by fatty tissue, which usually covers it. It is a wide but short trunk, usually no more than 10-11 mm long.

The left coronary artery is divided into two, three, in rare cases, four arteries, of which the anterior descending (LAD) and circumflex branches (OB), or arteries, are of greatest importance for pathology.

The anterior descending artery is a direct continuation of the left coronary artery.

Along the anterior longitudinal cardiac groove it is directed to the region of the apex of the heart, usually reaches it, sometimes bends over it and passes to the posterior surface of the heart.

Several smaller lateral branches depart from the descending artery at an acute angle, which are directed along the anterior surface of the left ventricle and can reach the obtuse edge; in addition, numerous septal branches depart from it, piercing the myocardium and branching in the anterior 2/3 of the interventricular septum. The lateral branches supply the anterior wall of the left ventricle and give branches to the anterior papillary muscle of the left ventricle. The superior septal artery gives off a branch to the anterior wall of the right ventricle and sometimes to the anterior papillary muscle of the right ventricle.

Throughout its entire length, the anterior descending branch lies on the myocardium, sometimes plunging into it to form muscle bridges 1-2 cm long. Throughout the rest of its length, its anterior surface is covered with fatty tissue of the epicardium.

The circumflex branch of the left coronary artery usually departs from the latter at the very beginning (the first 0.5-2 cm) at an angle close to a straight line, passes in the transverse groove, reaches the obtuse edge of the heart, goes around it, passes to back wall of the left ventricle, sometimes reaches the posterior interventricular groove and, in the form of the posterior descending artery, goes to the apex. Numerous branches extend from it to the anterior and posterior papillary muscles, the anterior and posterior walls of the left ventricle. One of the arteries supplying the sinoauricular node also departs from it.

Right coronary artery.

The right coronary artery originates in the anterior sinus of Vilsalva. First, it is located deep in the adipose tissue to the right of the pulmonary artery, bends around the heart along the right atrioventricular groove, passes to the posterior wall, reaches the posterior longitudinal groove, and then, in the form of a posterior descending branch, descends to the apex of the heart.

The artery gives 1-2 branches to the anterior wall of the right ventricle, partially to anterior section septum, both papillary muscles of the right ventricle, the posterior wall of the right ventricle and posterior section interventricular septum; a second branch also departs from it to the sinoauricular node.

There are three main types of blood supply to the myocardium:middle, left and right. This division is based mainly on variations in the blood supply to the posterior or diaphragmatic surface of the heart, since the blood supply to the anterior and lateral sections is quite stable and is not subject to significant deviations.

At average type all three main coronary arteries are well developed and fairly evenly developed. The blood supply to the entire left ventricle, including both papillary muscles, and the anterior 1/2 and 2/3 of the interventricular septum is carried out through the left coronary artery system. The right ventricle, including both right papillary muscles and the posterior 1/2-1/3 of the septum, receives blood from the right coronary artery. This appears to be the most common type of blood supply to the heart.

At left type blood supply to the entire left ventricle and, in addition, to the entire septum and partially to the posterior wall of the right ventricle is carried out due to the developed circumflex branch of the left coronary artery, which reaches the posterior longitudinal sulcus and ends here in the form of the posterior descending artery, giving some branches to the posterior surface of the right ventricle .

Right type observed with weak development of the circumflex branch, which either ends before reaching the obtuse edge, or passes into the coronary artery of the obtuse edge, without spreading to the posterior surface of the left ventricle. In such cases, the right coronary artery, after the origin of the posterior descending artery, usually gives several more branches to the posterior wall of the left ventricle. In this case, the entire right ventricle, the posterior wall of the left ventricle, the posterior left papillary muscle and partly the apex of the heart receive blood from the right coronary arteriole.

Blood supply to the myocardium is carried out directly :

a) capillaries lying between muscle fibers, entwining them and receiving blood from the coronary artery system through arterioles;

b) a rich network of myocardial sinusoids;

c) Viessant-Tebesius vessels.

As pressure in the coronary arteries increases and the work of the heart increases, blood flow in the coronary arteries increases. Lack of oxygen also leads to a sharp increase in coronary blood flow. The sympathetic and parasympathetic nerves appear to have little effect on the coronary arteries, exerting their main action directly on the heart muscle.

Outflow occurs through veins that collect in the coronary sinus

Venous blood in the coronary system collects in large vessels, usually located near the coronary arteries. Some of them merge, forming a large venous canal - the coronary sinus, which runs along the posterior surface of the heart in the groove between the atria and ventricles and opens into right atrium.

Intercoronary anastomoses play important role V coronary circulation, especially in pathological conditions. There are more anastomoses in the hearts of people suffering from coronary artery disease, so closure of one of the coronary arteries is not always accompanied by necrosis in the myocardium.

In normal hearts, anastomoses are found only in 10-20% of cases, and of small diameter. However, their number and magnitude increase not only with coronary atherosclerosis, but also with valvular heart defects. Age and gender by themselves do not have any effect on the presence and degree of development of anastomoses.

Heart (cor)

The circulatory system consists of a huge number of elastic vessels of various structures and sizes - arteries, capillaries, veins. In the center circulatory system there is a heart - a living suction-discharge pump.

Structure of the heart. The heart is the central apparatus of the vascular system, with a high degree of automatic action. In humans it is located in chest behind sternum, mostly (2/3) in the left half.

The heart lies (Fig. 222) on the tendon center of the diaphragm almost horizontally, located between the lungs in anterior mediastinum. It occupies an oblique position and faces its wide part (base) upward, back and to the right, and its narrower cone-shaped part (top) forward, down and left. The upper border of the heart is located in the second intercostal space; the right border protrudes approximately 2 cm beyond the right edge of the sternum; the left border passes without reaching the midclavicular line (passing through the nipple in men) by 1 cm. The apex of the cardiac cone (the junction of the right and left contour lines of the heart) is placed in the fifth left intercostal space down from the nipple. In this place, at the moment of contraction of the heart, a cardiac impulse is felt.

Rice. 222. Position of the heart and lungs. 1 - heart in a heart shirt; 2 - diaphragm; 3 - tendon center of the diaphragm; 4 - thymus gland; 5 - lung; 6 - liver; 7 - falciform ligament; 8 - stomach; 9 - innominate artery; 10 - subclavian artery; 11 - common carotid arteries; 12 — thyroid gland; 13 — thyroid cartilage; 14 - superior vena cava

In shape (Fig. 223), the heart resembles a cone, with its base facing upward and its apex downward. Large blood vessels enter and exit the wide part of the heart, the base. The weight of the heart in healthy adults ranges from 250 to 350 g (0.4-0.5% of body weight). By the age of 16, the weight of the heart increases 11 times compared to the weight of the heart of a newborn (V.P. Vorobyov). Average dimensions of the heart: length 13 cm, width 10 cm, thickness (antero-posterior diameter) 7-8 cm. The volume of the heart is approximately equal to the clenched fist of the person to whom it belongs. Of all vertebrates, birds have the largest relative heart size, requiring a particularly powerful motor to move blood.

Rice. 223. Heart (front view). 1 - innominate artery; 2 - superior vena cava; 3 - ascending aorta; 4 - coronary groove with the right coronary artery; 5 - right ear; 6 - right atrium; 7 - right ventricle; 8 - apex of the heart; 9 - left ventricle; 10 - anterior longitudinal groove; 11 - left ear; 12 - left pulmonary veins; 13 - pulmonary artery; 14 — aortic arch; 15 - left subclavian artery; 16 - left general carotid artery

In higher animals and humans, the heart is four-chambered, that is, it consists of four cavities - two atria and two ventricles; its walls consist of three layers. The most powerful and most important functionally is the muscle layer - the myocardium. The muscle tissue of the heart is different from skeletal muscle; it also has transverse striations, but the ratio of cell fibers is different than in skeletal muscles. The muscle bundles of the heart muscle have a very complex arrangement (Fig. 224). In the walls of the ventricles it is possible to trace three muscle layers: the outer longitudinal, the middle annular and the inner longitudinal. Between the layers there are transition fibers that make up the predominant mass. The outer longitudinal fibers, deepening obliquely, gradually turn into annular fibers, which also gradually turn obliquely into internal longitudinal ones; The papillary muscles of the valves are also formed from the latter. On the very surface of the ventricles there are fibers that cover both ventricles together. Such a complex course of muscle bundles provides the most complete reduction and emptying of the cavities of the heart. Muscle layer The walls of the ventricles, especially the left one, which drives blood in a large circle, are much thicker. The muscle fibers that form the walls of the ventricles are collected from the inside into numerous bundles, which are located in different directions, forming fleshy crossbars (trabeculae) and muscle protrusions - papillary muscles; From them, tendon cords go to the free edge of the valves, which stretch during contraction of the ventricles and do not allow the valves to open in the atrium cavity under the pressure of blood.

Rice. 224. Course of the muscle fibers of the heart (semi-schematic)

The muscle layer of the walls of the atria is thin, since their load is small - they only drive blood into the ventricles. Superficial muscle pikes facing the inside of the atrium cavity form the pectineus muscles.

WITH outer surface on the heart (Fig. 225, 226) two grooves are noticeable: longitudinal, covering the heart in front and behind, and transverse (coronal), located in a ring shape; The heart's own arteries and veins run along them. These grooves inside correspond to partitions that divide the heart into four cavities. The longitudinal interatrial and interventricular septum divides the heart into two halves completely isolated from one another - the right and left heart. The transverse septum divides each of these halves into an upper chamber - the atrium (atrium) and a lower chamber - the ventricle (ventriculus). Thus, two atria and two separate ventricles are obtained that do not communicate with each other. The superior vena cava, inferior vena cava and coronary sinus flow into the right atrium; The pulmonary artery arises from the right ventricle. The right and left pulmonary veins flow into the left atrium; The aorta arises from the left ventricle.

Rice. 225. Heart and large vessels (front view). 1 - left common carotid artery; 2 - left subclavian artery; 3 - aortic arch; 4 - left pulmonary veins; 5 - left ear; 6 - left coronary artery; 7 - pulmonary artery (cut off); 8 - left ventricle; 9 - apex of the heart; 10 - descending aorta; 11 - inferior vena cava; 12 - right ventricle; 13 - right coronary artery; 14 - right ear; 15 - ascending aorta; 16 - superior vena cava; 17 - innominate artery

Rice. 226. Heart (back view). 1 - aortic arch; 2 - left subclavian artery; 3 - left common carotid artery; 4 - azygos vein; 5 - superior vena cava; 6 - right pulmonary veins; 7 - inferior vena cava; 8 - right atrium; 9 - right coronary artery; 10 - middle vein of the heart; 11 - descending branch of the right coronary artery; 12 - right ventricle; 13 - apex of the heart; 14 - diaphragmatic surface of the heart; 15 - left ventricle; 16-17 - common drainage of the cardiac veins (coronary sinus); 18 - left atrium; 19 - left pulmonary veins; 20 - branches of the pulmonary artery

The right atrium communicates with the right ventricle through the right atrioventricular orifice (ostium atrioventriculare dextrum); and the left atrium with the left ventricle - through the left atrioventricular orifice (ostium atrioventriculare sinistrum).

The upper part of the right atrium is the right ear of the heart (auricula cordis dextra), which has the shape of a flattened cone and is located on the anterior surface of the heart, covering the aortic root. In the cavity of the right ear, the muscle fibers of the atrium wall form parallel muscle ridges.

The left cardiac appendage (auricula cordis sinistra) extends from the anterior wall of the left atrium, in the cavity of which there are also muscle ridges. The walls in the left atrium are smoother from the inside than in the right.

The inner membrane (Fig. 227), lining the inside of the heart cavities, is called the endocardium; it is covered with a layer of endothelium (a derivative of mesenchyme), which extends to the inner lining of the vessels extending from the heart. At the border between the atria and ventricles there are thin lamellar outgrowths of the endocardium; here the endocardium, as if folded in half, forms strongly protruding folds, also covered on both sides with endothelium, these are the heart valves (Fig. 228), closing the atrioventricular openings. In the right atrioventricular orifice there is a tricuspid valve (valvula tricuspidalis), consisting of three parts - thin fibrous elastic plates, and in the left - a bicuspid valve (valvula bicuspidalis, s. mytralis), consisting of two of the same plates. These leaflet valves open during atrial systole only towards the ventricles.

Rice. 227. Heart of an adult with the ventricles opened in front. 1 - ascending aorta; 2 - ligament arteriosus (overgrown ductus botallus); 3 - pulmonary artery; 4 - semilunar valves of the pulmonary artery; 5 - left ear of the heart; 6 - anterior leaf of the bicuspid valve; 7 - anterior papillary muscle; 8 - posterior leaf of the bicuspid valve; 9 - tendon threads; 10 - posterior papillary muscle; 11 - left ventricle of the heart; 12 - right ventricle of the heart; 13 - posterior leaf of the tricuspid valve; 14 - medial leaflet of the tricuspid valve; 15 - right atrium; 16 - anterior leaflet of the tricuspid valve, 17 - conus arteriosus; 18 - right ear

Rice. 228. Heart valves. Opened heart. The direction of blood flow is shown by arrows. 1 - bicuspid valve of the left ventricle; 2 - papillary muscles; 3 - semilunar valves; 4 - tricuspid valve of the right ventricle; 5 - papillary muscles; 6 - aorta; 7 - superior vena cava; 8 - pulmonary artery; 9 - pulmonary veins; 10 - coronary vessels

At the exit of the aorta from the left ventricle and the pulmonary artery from the right ventricle, the endocardium also forms very thin folds in the form of concave (into the ventricular cavity) semicircular pockets, three in each opening. Due to their shape, these valves are called semilunar valves (valvulae semilunares). They open only upward towards the vessels during contraction of the ventricles. During the relaxation (expansion) of the ventricles, they automatically close and do not allow the reverse flow of blood from the vessels into the ventricles; when the ventricles contract, they open again with the flow of expelled blood. The semilunar valves are devoid of muscle.

From the above it is clear that in humans, as in other mammals, the heart has four valve systems: two of them, cusp valves, separate the ventricles from the atria, and two, semilunar, separate the ventricles from the arterial system. There are no valves at the point where the pulmonary veins enter the left atrium; but the veins approach the heart at an acute angle in such a way that the thin wall of the atrium forms a fold, acting in part as a valve or flap. In addition, there are thickenings of ring-shaped muscle fibers of the adjacent part of the atrial wall. These thickenings muscle tissue During contraction of the atria, the mouths of the veins are compressed and this prevents the reverse flow of blood into the veins, so that it flows only into the ventricles.

In an organ that performs such a big job as the heart, support structures naturally develop to which the muscle fibers of the heart muscle are attached. This soft cardiac “skeleton” includes: tendon rings around its openings equipped with valves, fibrous triangles located at the root of the aorta and the membranous part of the ventricular septum; they all consist of bundles of collagen fibrils with an admixture of elastic fibers.

Heart valves consist of dense and elastic connective tissue (endocardial duplication - duplication). When the ventricles contract, the leaflet valves, under the pressure of blood in the cavities of the ventricles, straighten out, like stretched sails, and touch so tightly that they completely close the openings between the cavities of the atria and the cavities of the ventricles. At this time, they are supported by the tendon threads mentioned above and prevent them from turning inside out. Therefore, blood from the ventricles cannot return to the atria; under the pressure of the contracting ventricles, it is pushed from the left ventricle into the aorta, and from the right into the pulmonary artery. Thus, all heart valves open only in one direction - in the direction of blood flow.

The size of the cavities of the heart varies depending on the degree of filling with blood and the intensity of its work. Thus, the capacity of the right atrium ranges from 110-185 cm3, the right ventricle - from 160 to 230 cm3, the left atrium - from 100 to 130 cm3 and the left ventricle - from 143 to 212 cm3.

The heart is covered with thin serosa, forming two leaves that pass into one another at the point where large vessels depart from the heart. The inner, or visceral, leaf of this sac, directly covering the heart and tightly fused to it, is called the epicardium (epieardium), the outer, or parietal, leaf is called the pericardium (pericardium). The parietal layer forms a sac that encloses the heart - this is the cardiac sac, or cardiac sac. The pericardium is adjacent to the layers of the mediastinal pleura on the sides, grows from below to the tendon center of the diaphragm, and in front is attached by connective tissue fibers to the posterior surface of the sternum. Between both leaves of the cardiac sac, a slit-like hermetically closed cavity is formed around the heart, always containing a certain amount (about 20 g) of serous fluid. The pericardium insulates the heart from the surrounding organs, and the fluid moisturizes the surface of the heart, reducing friction and making its movements gliding during contractions. Moreover, it is strong fibrous tissue the pericardium limits and prevents excessive stretching of the muscle fibers of the heart; if there were no pericardium to anatomically limit the volume of the heart, it would be in danger of overextension, especially during periods of its most intense and unusual activity.

Incoming and outgoing vessels of the heart. The superior and inferior vena cava drain into the right atrium. At the confluence of these veins, a wave of contraction of the heart muscle occurs, quickly covering both atria and then moving to the ventricles. In addition to the large vena cava, the coronary sinus of the heart (sinus eoronarius cordis) also flows into the right atrium, through which venous blood flows here from the walls of the heart itself. The sinus opening is closed by a small fold (tebesian valve).

The four-year-old veins drain into the left atrium. The largest artery in the body, the aorta, emerges from the left ventricle. It first goes to the right and up, then, bending back and to the left, it spreads over the left bronchus in the form of an arc. The pulmonary artery emerges from the right ventricle; it goes first to the left and up, then turns to the right and divides into two branches heading to both lungs.

In total, the heart has seven inlet - venous - holes and two outlet - arterial - holes.

Circulation circles(Fig. 229). Thanks to the long and complex evolution of the development of the circulatory organs, a certain system of supplying the body with blood, characteristic of humans and all mammals, has been established. As a rule, blood moves inside a closed system of tubes, which includes a constantly operating powerful muscular organ- heart. The heart, as a result of its historically established automatism and regulation by the central nervous system, continuously and rhythmically pumps blood throughout the body.

Rice. 229. Scheme of blood circulation and lymph circulation. Vessels through which the flow flows are indicated in red. arterial blood; blue - vessels with venous blood; the portal vein system is shown in purple; yellow - lymphatic vessels. 1 - right half of the heart; 2 - left half of the heart; 3 - aorta; 4 - pulmonary veins; superior and inferior vena cava; 6 - pulmonary artery; 7 - stomach; 8 - spleen; 9 - pancreas; 10 - intestines; 11 - portal vein; 12 - liver; 13 - kidney

Blood from the left ventricle of the heart first flows through the aorta into large arteries, which gradually branch into smaller ones and then pass into arterioles and capillaries. Through the thinnest walls capillaries constantly exchange substances between blood and body tissues. Passing through a dense and numerous network of capillaries, the blood gives oxygen and nutrients to the tissues, and receives in return carbon dioxide and products of cellular metabolism. Changing in its composition, the blood subsequently becomes unsuitable for maintaining respiration and nutrition of cells; it turns from arterial to venous. The capillaries begin to gradually merge, first into venules, venules into small veins, and the latter into large venous vessels - the superior and inferior vena cava, through which blood returns to the right atrium of the heart, thus describing the so-called large, or bodily, circle of blood circulation.

Coming from the right atrium to the right ventricle venous blood, the heart sends it through the pulmonary artery to the lungs, where in the smallest network of pulmonary capillaries it is freed from carbon dioxide and saturated with oxygen, and then returns again through the pulmonary veins to the left atrium, and from there to the left ventricle of the heart, from where it again supplies the body tissues. The circulation of blood on the way from the heart through the lungs and back is the pulmonary circulation. The heart not only performs the work of a motor, but also acts as a device that controls the movement of blood. Switching blood from one circuit to another is achieved (in mammals and birds) by complete separation of the right (venous) half of the heart from its left (arterial) half.

These phenomena in the circulatory system have become known to science since the time of Harvey, who discovered blood circulation (1628), and Malpighi (1661), who established blood circulation in the capillaries.

Blood supply to the heart(see Fig. 226). The heart, performing an extremely important service in the body and performing enormous work, itself needs plenty of food. This is an organ that is in an active state throughout a person’s life and never has a rest period that lasts more than 0.4 seconds. Naturally, this organ must be supplied with a particularly abundant amount of blood. Therefore, its blood supply is designed in such a way that it completely ensures the inflow and outflow of blood.

The heart muscle receives blood first of all other organs through two coronary (coronary) arteries (a. eoronaria cordis dextra et sinistra), extending directly from the aorta just above the semilunar valves. Even at rest, the abundantly developed network of coronary vessels of the heart receives about 5-10% of all blood ejected into the aorta. The right coronary artery runs along the transverse groove to the right towards the posterior half of the heart. It supplies most of the right ventricle, the right atrium, and part of the posterior side of the left heart. Its branch feeds the conduction system of the heart - the Ashof-Tavara node, the bundle of His (see below). The left coronary artery divides into two branches. One of them runs along the longitudinal groove to the apex of the heart, giving numerous lateral branches, the other runs along the transverse groove to the left and posteriorly to the posterior longitudinal groove. The left coronary artery supplies most of the left heart and the anterior part of the right ventricle. The coronary arteries split into large number branches, widely interconnecting with each other and crumbling into a very dense network of capillaries, penetrating everywhere, into all parts of the organ. The heart has 2 times more (thicker) capillaries than skeletal muscle.

Venous blood flows from the heart through numerous channels, of which the most significant is the coronary sinus (or a special coronary vein - sinus coronarius cordis), which flows directly into the right atrium. All other veins that collect blood from individual areas cardiac muscle, also open directly into the cavity of the heart: into the right atrium, into the right and even into the left ventricle. It turns out that 3/5 of all the blood passing through the coronary vessels flows through the coronary sinus, while the remaining 2/5 of the blood is collected by other venous trunks.

The heart is permeated with the richest network lymphatic vessels. The entire space between muscle fibers and blood vessels The heart is a dense network of lymphatic vessels and slits. Such an abundance of lymphatic vessels is necessary for quick removal metabolic products, which is very important for the heart as an organ that works continuously.

From the above it is clear that the heart has its own third circle of blood circulation. Thus, the coronary circle is connected parallel to the entire systemic circulation.

The coronary circulation, in addition to nourishing the heart, also has a protective significance for the body, significantly softening harmful effects excessively high blood pressure due to sudden contraction (spasm) of many peripheral vessels great circle blood circulation; in this case, a significant part of the blood is sent along a parallel short and widely branched coronary tract.

Innervation of the heart(Fig. 230). Heart contractions occur automatically due to the properties of the heart muscle. But the regulation of its activity, depending on the needs of the body, is carried out by the central nervous system. I. P. Pavlov said that “the activity of the heart is controlled by four centrifugal nerves: slowing down, accelerating, weakening and strengthening.” These nerves approach the heart as part of branches from vagus nerve and from the nodes of the cervical and thoracic sympathetic trunk. The branches of these nerves form a plexus on the heart (plexus cardiacus), the fibers of which spread along with the coronary vessels of the heart.

Rice. 230. Conducting system of the heart. Diagram of the location of the conduction system in the human heart. 1 - Kis-Flaka knot; 2 - Ashof-Tavara knot; 3 - bundle of His; 4 - bundle branches; 5 - Purkinje fiber network; 6 - superior vena cava; 7 - inferior vena cava; 8 - atria; 9 - ventricles

Coordination of the activity of parts of the heart, atria, ventricles, the sequence of contractions and relaxations is carried out by a special conduction system peculiar only to the heart. The cardiac muscle has the peculiarity that impulses are conducted to the muscle fibers through special atypical muscle fibers called Purkinje fibers, which form the conduction system of the heart. Purkinje fibers are similar in structure to muscle fibers and directly pass into them. They look like wide ribbons, are poor in myofibrils and very rich in sarcoplasm. Between the right ear and the superior vena cava, these fibers form the sinus node (Kis-Flaka node), which is connected by a bundle of the same fibers to another node (Ashof-Tavara node), located on the border between the right atrium and the ventricle. A large bundle of fibers (bundle of His) departs from this node, which descends in the ventricular septum, dividing into two legs, and then scatters in the walls of the right and left ventricles under the epicardium, ending in the papillary muscles.

Fibers of the nervous system everywhere come into close contact with Purkinje fibers.

The bundle of His is the only muscular connection between the atrium and the ventricle; through it, the initial stimulus arising in the sinus node is transmitted to the ventricle and ensures the completeness of cardiac contraction.

Blood, thanks to the “internal motor” - the heart, circulates throughout the body, saturating every cell with nutrients and oxygen. How does the heart itself receive nutrition? Where does it get its reserves and strength for work? And do you know about the so-called third circle of blood circulation or heart? To better understand the anatomy of the vessels supplying the heart, let's look at the main anatomical structures that are usually identified in the central organ of the cardiovascular system.

1 External structure of the human “motor”

First-year students at medical colleges and medical universities learn by heart, and even in Latin, that the heart has an apex, a base, and two surfaces: the anterior superior and inferior, separated by edges. Naked eye you can see the cardiac grooves by looking at its surface. There are three of them:

1. coronal sulcus,
2. Anterior interventricular
3. Posterior interventricular.

The atria are visually separated from the ventricles by the coronary groove, and the border between the two lower chambers along the anterior surface is approximately the anterior interventricular groove, and along the rear surface the interventricular posterior groove. The interventricular grooves join at the apex slightly to the right. These grooves were formed due to the vessels running in them. In the coronary groove, which separates the cardiac chambers, there is the right coronary artery, the sinus veins, and in the anterior interventricular groove, which separates the ventricles, there is a large vein and an anterior interventricular branch.

The posterior interventricular groove is the receptacle for the interventricular branch of the right coronary artery, the middle cardiac vein. The abundance of numerous medical terminology can make your head spin: furrows, arteries, veins, branches... Of course, because we are analyzing the structure and blood supply of the most important human organ- hearts. If it were simpler, would it be able to perform such complex and responsible work? Therefore, let's not give up halfway, and analyze in detail the anatomy of the heart vessels.

2 3rd or cardiac circle of blood circulation

Every adult knows that there are 2 circles of blood circulation in the body: large and small. But anatomists say that there are three of them! So is the basic anatomy course misleading? Not at all! The third circle, named figuratively, refers to the vessels that fill the blood and “serve” the heart itself. It deserved personal vessels, didn’t it? So the 3rd or heart circle begins coronary arteries, which are formed from the main vessel human body- Her Majesty's aorta, and ends with the cardiac veins, merging into the coronary sinus.

It in turn opens in . And the smallest venules open into the atrial cavity on their own. It was noticed very figuratively that the vessels of the heart entwine and envelop it like a real crown, a crown. Therefore, arteries and veins are called coronary or coronary. Remember: these are synonymous terms. So what are the most important arteries and veins the heart has at its disposal? What is the classification of coronary arteries?

3 Main arteries

The right coronary artery and the left coronary artery are two whales that deliver oxygen and nutrients. They have branches and offshoots, which we will discuss later. For now, let’s understand that the right coronary artery is responsible for filling the right heart chambers, the walls of the right ventricle and the posterior wall of the left ventricle, and the left coronary artery supplies blood to the left heart chambers.

The right coronary artery goes around the heart along the coronary sulcus on the right, giving off the posterior interventricular branch (posterior descending artery), which descends to the apex, located in the posterior interventricular sulcus. The left coronary also lies in the coronary sulcus, but on the other, opposite side - in front of the left atrium. It is divided into two important branches - the anterior interventricular (anterior descending artery) and the circumflex artery.

The path of the anterior interventricular branch runs in the recess of the same name, to the apex of the heart, where our branch meets and merges with the branch of the right coronary artery. And the left circumflex artery continues to “hug” the heart on the left along the coronary sulcus, where it also unites with the right coronary. Thus, nature created an arterial ring of coronary vessels on the surface of the human “motor” in a horizontal plane.

This is an adaptive element, in case a vascular catastrophe suddenly occurs in the body and blood circulation sharply deteriorates, then despite this the heart will be able to maintain blood supply and its work for some time, or if one of the branches is blocked by a thrombus, the blood flow will not stop, but will continue through another cardiac vessel. The ring is collateral circulation organ.

The branches and their smallest branches penetrate the entire thickness of the heart, supplying blood not only to the upper layers, but to the entire myocardium and the inner lining of the chambers. Intramuscular arteries follow the course of the muscular cardiac bundles; each cardiomyocyte is saturated with oxygen and nutrition due to a well-developed system of anastomoses and arterial blood supply.

It should be noted that in a small percentage of cases (3.2-4%), people have such an anatomical feature as a third coronary artery or an additional one.

4 Forms of blood supply

There are several types of blood supply to the heart. All of them are a variant of the norm and a consequence individual characteristics laying of the heart vessels and their functioning in each person. Depending on the prevailing distribution of one of the coronary arteries on the posterior heart wall, they are distinguished:

1. Legal type. With this type of blood supply to the heart, the left ventricle (posterior surface of the heart) is filled with blood primarily from the right coronary artery. This type of blood supply to the heart is the most common (70%)
2. Left-handed type. Occurs if the left coronary artery predominates in the blood supply (in 10% of cases).
3. Uniform type. With approximately equal “contribution” to the blood supply of both vessels. (20%).

5 Major veins

Arteries branch into arterioles and capillaries, which, having completed cellular exchange and taking decay products and carbon dioxide from cardiomyocytes, are organized into venules, and then larger veins. Venous blood can flow into venous sinus(from it the blood then enters the right atrium), or into the atrial cavity. The most significant cardiac veins that drain blood into the sinus are:

1. Big. It takes venous blood from the anterior surface of the two lower chambers and lies in the interventricular anterior groove. The vein begins at the apex.
2. Average. It also originates at the apex, but runs along the posterior groove.
3. Small. It can flow into the middle one and is located in the coronal sulcus.

The veins that drain directly into the atria are the anterior and smallest cardiac veins. The smallest veins are not named so by chance, because the diameter of their trunks is very small; these veins do not appear on the surface, but lie in the heart deep tissues and open mainly into the upper chambers, but can also pour into the ventricles. The anterior cardiac veins supply blood to the right upper chamber. In this way, you can imagine in the most simplified way how the blood supply to the heart occurs and the anatomy of the coronary vessels.

Once again I would like to emphasize that the heart has its own, personal, coronary circle of blood circulation, thanks to which separate blood circulation can be maintained. The most important cardiac arteries are the right and left coronary, and the veins are large, middle, small, and anterior.

6 Diagnostics of coronary vessels

Coronary angiography is the “gold standard” in diagnosing coronary arteries. This is the most accurate method; it is performed in specialized hospitals by highly qualified medical workers, the procedure is performed according to indications, under local anesthesia. The doctor inserts a catheter through the artery of the arm or thigh, and through it a special radiopaque agent, which, mixing with blood, spreads, making both the vessels themselves and their lumen visible.

Pictures and video recordings of the filling of the vessels with the substance are taken. The results allow the doctor to make a conclusion about the patency of the vessels, the presence of pathology in them, assess the prospects for treatment and the possibility of recovery. Diagnostic methods for studying coronary vessels also include MSCT angiography, ultrasound examination with Doppler, electron beam tomography.

The arteries of the heart depart from the aortic bulb - the initial expanded section of the ascending aorta and, like a crown, surround the heart, and therefore are called coronary arteries. The right coronary artery begins at the level of the right aortic sinus, and the left coronary artery begins at the level of its left sinus. Both arteries depart from the aorta below the free (upper) edges of the semilunar valves, therefore, during contraction (systole) of the ventricles, the valves cover the openings of the arteries and almost do not allow blood to pass to the heart. When the ventricles relax (diastole), the sinuses fill with blood, closing its path from the aorta back to the left ventricle, and at the same time opening the access of blood to the vessels of the heart.

Right coronary artery

It goes to the right under the appendage of the right atrium, lies in the coronary groove, goes around the right pulmonary surface of the heart, then follows its posterior surface to the left, where its end anastomoses with the circumflex branch of the left coronary artery. The largest branch of the right coronary artery is the posterior interventricular branch, which is directed along the same groove of the heart towards its apex. The branches of the right coronary artery supply blood to the wall of the right ventricle and atrium, the posterior part of the interventricular septum, the papillary muscles of the right ventricle, the posterior papillary muscle of the left ventricle, the sinoatrial and atrioventricular nodes of the conduction system of the heart.

Left coronary artery

Slightly thicker than the right one. Located between the beginning of the pulmonary trunk and the left atrial appendage, it is divided into two branches: the anterior interventricular branch and the circumflex branch. The latter, which is a continuation of the main trunk of the coronary artery, bends around the heart on the left, located in its coronary sulcus, where on the posterior surface of the organ it anastomoses with the right coronary artery. The anterior interventricular branch follows the same groove of the heart towards its apex. In the area of ​​the cardiac notch, it sometimes passes to the diaphragmatic surface of the heart, where it anastomoses with the terminal section of the posterior interventricular branch of the right coronary artery. Branches of the left coronary artery supply the wall of the left ventricle, including the papillary muscles, most of the interventricular septum, the anterior wall of the right ventricle, and the wall of the left atrium.

The branches of the right and left coronary arteries, connecting, form two arterial rings in the heart: a transverse one, located in the coronary groove, and a longitudinal one, the vessels of which are located in the anterior and posterior interventricular grooves.

The branches of the coronary arteries provide blood supply to all layers of the walls of the heart. In the myocardium, where the level of oxidative processes is highest, microvessels anastomosing among themselves repeat the course of the muscle fiber bundles of its layers.

There are different options for the distribution of branches of the coronary arteries, which are called types of blood supply to the heart. The main ones are the following: right coronary, when most parts of the heart are supplied with blood by the branches of the right coronary artery; left coronary, when most of the heart receives blood from the branches of the left coronary artery, and middle, or uniform, in which both coronary arteries evenly participate in the blood supply to the walls of the heart. There are also transitional types of blood supply to the heart - middle-right and middle-left. It is generally accepted that among all types of blood supply to the heart, the middle-right type is predominant.

Variations and anomalies in the position and branching of the coronary arteries are possible. They manifest themselves in changes in the origin and number of coronary arteries. Thus, the latter can arise from the aorta directly above the semilunar valves or much higher - from the left subclavian artery, and not from the aorta. The coronary artery may be the only one, that is, unpaired, there may be 3 - 4 coronary arteries, and not two: two arteries depart to the right and left of the aorta, or two from the aorta and two from the left subclavian artery.

Along with the coronary arteries, non-permanent (accessory) arteries go to the heart (especially to the pericardium). These may be the mediastinal-pericardial branches (upper, middle and lower) of the internal thoracic artery, branches of the pericardial-phragmatic artery, branches extending from the concave surface of the aortic arches, etc.