Major 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 that supply blood from the chambers, like the spongy subendocardium in adult frogs. As the embryo grows, the walls of the heart thicken, the muscle layers are more compact. Intramural coronary arteries, capillaries, and veins are formed from intramuscular sinusoids to supply the metabolically active myocardium with substrates. 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, protruding toward the apex of the heart. They develop penetrating branches that enter the myocardium and connect with the primitive system of sinusoids. The same rudiments are laid at the base of the pulmonary artery.

Accessory coronary arteries

These coronary arteries are typical branches of the coronary arteries, which depart from the sinuses of Valsalva by an independent mouth, so only their mouth is additional. The most common pathology of the right coronary artery. The presence of 2 to 5 additional orifices in the right coronary sinus is described. Its first branch - the artery of the cone - in 50% of patients departs in the form of an independent artery from the right sinus of Valsalva. 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 depart as independent mouths from the left sinus. The anterior descending artery can depart by an independent mouth from the right sinus. The first branch of the penetrating coronary artery can depart from the left coronary sinus by a separate mouth.

None of these variants of the anatomy of the coronary arteries has clinical implications and is not included in the list of anomalies of the coronary arteries.

Stenosis and atresia of the mouth of the coronary artery

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 blood circulation is carried out through expanded sinusoids that have a connection with the coronary arteries. El-Said et al described atresia of the left coronary artery in a 14-year-old boy who complained of heart pain, exercise fatigue, and syncope. He had a systolic murmur at the apex, ventricular extrasystoles were periodically recorded on the ECG, and a displacement of the ST segment below the isoline by 3 mm was noted during bicycle ergometry. Coronary angiography revealed retrograde filling of the left coronary artery through collaterals. The authors completed coronary artery bypass grafting using v. saphena. similarity clinical symptoms and ECG data in such patients with endocardial fibroelastosis is the reason for the diagnosis of isolated fibroelastosis or abnormal origin of the left coronary artery from pulmonary trunk. Molander described the case history of a 19-year-old boy who had been observed 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 depart from the aorta at a right angle. Witat et al analyzed 22 cases sudden death adult people. In 10 of them, the right coronary artery and in 3, both coronary arteries departed from the aorta along a tangent, 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 gap, 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 a 5-month-old infant has been reported to have died from this cause.

If this anomaly is detected by echocardiography or coronary angiography, surgical intervention should be undertaken.

Abnormal path of the coronary artery between the aorta and the pulmonary artery

One of the coronary arteries may pass between the aorta and the pulmonary trunk with normal origin from various sinuses. The unnatural path of the artery is also found in various variants of 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 extending from the left sinus of the aorta and the right coronary artery, passing between the main arteries.

When the mouths of both coronary arteries are in the same sinus, the mouth of the abnormal artery may have a slit-like shape.

The artery passing between the aorta and the pulmonary trunk can be infringed by the myocardium, especially during exercise, and cause sudden death. Patients are often asymptomatic until fainting occurs. frequency and natural flow abnormal location of the coronary arteries between the main vessels have not been studied. All patients with anginal pain and fainting spells coronary angiography is indicated and, if this pathology is detected, surgical intervention.

If there are two ostia in the same sinus, the operation involves the expansion and remodeling of the abnormal ostium to eliminate compression between the main arteries. In this case, shunting may be ineffective due to competing blood flow from the aorta and reduced blood flow through the anastomosis, followed by thrombosis. However, if there is only one coronary artery and the passage of the left main or right coronary artery between large vessels, the elimination of obstruction by reimplantation or remodeling of the orifice may not be possible, so bypass becomes the only choice.

Operation technique

After studying the anatomy and starting cardiopulmonary bypass, the aorta is clamped, the heart is relaxed, and the aorta is opened by a transverse incision. The orifice of the anomalous coronary artery is slit-like and narrow. Since the orifice may be located in close proximity to the commissure, it must be separated from the aortic wall. The orifice is cut along the long axis of the coronary artery and a part of the common wall between the aorta and the artery is cut. The artery is anastomosed to the aorta with 7/0 or 8/0 prolene. The aortic valve commissure is sutured into place with spacers. The aortic incision is sutured, the clamp is removed from the aorta after air is removed from the heart cavities. The operation is completed in the standard way.

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

Among all anomalies of the coronary arteries, the most common is the departure of the left circumflex coronary artery from the right coronary artery. The circumflex artery passes behind the aorta and reaches its normal area of ​​blood supply. This anomaly does not clinical significance, however, it can be squeezed with double prosthetic mitral and aortic valves. This artery is characterized high probability atherosclerotic plaque lesions.

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

behind the aorta;

in front of the excretory 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 right ventricular outflow tract.

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 major 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 the compression of the left coronary artery up to its occlusion. Preceding signs are dizziness and pain in the heart during physical exertion. At autopsy, in most cases, a slit-like orifice of the left main coronary artery was found, its origin from the aorta at an acute angle and its increment 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 often seen in tetralogy of Fallot. The artery usually passes along the anterior surface of the right ventricular outflow tract or in the thickness of the interventricular septum and rarely between the aorta and the right ventricular outflow tract. 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

Departure of the right main coronary artery from the left sinus of Valsalva accounts for 30% of all anomalies of the coronary arteries. The artery follows between the aorta and the outflow tract of the right ventricle, then passes in the atrioventricular sulcus and branches normally. This option is considered relatively benign, but there are many reports of myocardial ischemia, infarction and sudden death. IN clinical picture pain in the heart, arrhythmia at rest or during exercise predominate. During pathological anatomical studies, the right coronary artery often departed at an angle to the aorta, and the mouth had a slit-like shape.

Anomalies of the coronary vessels associated with CHD

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

Tetralogy of Fallot

About 40% of patients have an unusually long, large conus artery that supplies a significant mass of the myocardium. In 4-5% of cases, the anterior interventricular branch departs 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 ventricular outflow tract. Other, rare branching options are also possible. The main left coronary artery occasionally passes anterior to the pulmonary artery.

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

parallel to the course of the artery incision of the right ventricle;

incisions above and below the artery;

creation of 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 anatomy of the coronary arteries may influence the choice of palliative surgery.

Abnormal passage of the coronary arteries may be suspected by echocardiography and angiography of the aortic root. Although the surgeon sees the coronary arteries during the operation, it is important to establish an accurate diagnosis before the intervention in order to eliminate the surprise factor and plan an adequate operation in advance. In addition, if the patient has epicardial adhesions from a previous operation, or if the artery passes through the myocardium, it cannot be seen during the operation, so it can be severely severed. In this regard, in all patients who have previously undergone intrapericardial interventions, it is worth performing angiography of the aortic root. In practice, there have been episodes of intersection of a significant coronary artery, which required shunting of the internal mammary artery.

Full TMA

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

The coronary arteries arise predominantly from the adjacent sinuses. In 60% of cases, they depart from their own sinuses and branch normally when the aorta is located in front and somewhat to the right of the pulmonary artery. But since the aorta is located in front, 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 departs from the right adjacent sinus and then follows posteriorly to the pulmonary trunk, or departs from the left adjacent sinus and goes anteriorly to the right ventricular outflow tract. In 5% of cases, both main arteries originate from the same adjacent sinus, usually from the right, and one or both arteries pass intramurally, giving the impression that they originate from different sinuses. There may be other rare variants.

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

Corrected TMA

The aorta is located in front 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 the anatomy, there is confusion in the issue of naming coronary arteries that do not originate from their sinuses. Some authors describe the coronary vessels as right or left sided, according to the sinuses from which they originate. Others describe arteries by the territory they supply. This terminology is used here.

The left coronary artery supplies the anatomically left ventricle, however, departs 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 blood to the right ventricle. It originates from the left sinus accumbens and passes in the atrioventricular sulcus in front of the left atrial appendage, continuing as the posterior descending artery. The most common variant is a single coronary artery originating from the right sinus sinus accumbens.

Double inlet left ventricle

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

When the outlet chamber is located in front and on the right, the relative position of the aorta and pulmonary trunk is the same as with complete transposition. The right coronary artery arises from the right adjacent sinus of the aorta and passes in the right atrioventricular sulcus. The left main coronary artery originates from the left adjacent sinus and follows in the left atrioventricular sulcus as a circumflex artery. From the left and right coronary arteries depart, respectively, the left and right delimiting arteries.

When the outlet chamber is located in front and on the left, the orientation large vessels the same as in 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 delimit 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 it difficult to fix the artificial interventricular septum.

Right ventricle with two outlets

In most forms of this group of anomalies, the coronary arteries usually originate normally, except that due to the 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 in 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 originating anteriorly or posteriorly. Sometimes the left anterior descending artery arises from the right coronary artery and crosses the right ventricular outflow tract, as in tetralogy of Fallot. When the aorta is located on the left, the right coronary artery flows to the right from the anterior sinus of the aorta anterior to the pulmonary artery until it reaches the atrioventricular sulcus.

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 has to be abandoned. The most constant is the departure 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 orifices or a single orifice are important. Large diagonal branches 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

The only coronary artery was first described by Tebesi in 1716, followed by Hyrtl in 1841. As an isolated defect, this anomaly is extremely rare - 1 case in 2000-7000 of all coronary angiography performed, somewhat more often among males. Smith proposed the following classification of this anomaly:

The only 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 originate.

The only coronary artery with a circumflex location 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 of particular danger, especially in tetralogy of Fallot or other defects, accompanied by narrowing of the right ventricular outflow tract, requiring its plastic surgery. Anomalies of the right coronary artery are more common than those of the left. An isolated defect in the form of a single coronary artery can sometimes cause sudden death, ischemia, or myocardial infarction, especially when the left or right artery departs from the common trunk, or they jointly pass between the aorta and the trunk of the pulmonary artery.

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

Quite often, a single coronary artery is found in patients with Fallot's tetralogy. It occurs in 5% of children with TMA; in this case, the artery departs from the posterior sinus and is divided 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 mouths from one sinus of Valsalva. A normal origin of one coronary artery from the aorta with a branch of the left coronary artery 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. In the literature, there are many reports of cases of a single coronary artery, usually associated with other congenital heart disease, as well as cases of a single coronary artery with normal heart morphology.

Intramural passage of the coronary artery

In some cases, the initial section of the left coronary artery, extending from the right aortic sinus, is located in the thickness of the aortic wall. On histological examination, the vessels have a single median membrane, which is common to the aorta and coronary artery. This anatomical variant of the location of the coronary artery is sometimes the cause of sudden death. With the expansion during systole of the fibrous-rich ascending aorta, compression of the intramural segment of the left coronary artery occurs, which leads to myocardial ischemia. The treatment of this syndrome consists in surgical plasty of the coronary artery with the isolation of this segment from the aortic wall or in the imposition of a shunt to bypass the intramural segment.

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

"Diving Arteries"

Large epicardial coronary arteries normally run along the surface and only they terminal branches penetrate into the myocardium. In 50% of people, the coronary arteries in some places sink into the thickness of the myocardium, and then reappear on its surface. In these cases, a muscular bridge is formed over a large coronary artery. More often "mural" is the left anterior descending branch in its proximal half. This anomaly is found in both infants and the elderly. At the age of up to 20 years, the length of the immersed part is on average 14 mm, at an older age - 20-30 mm. In about 75% of cases, the anterior descending coronary artery passes in the interventricular sulcus 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 value especially if they are superficial. However, cases are described when, during exercise, the submerged part of the coronary artery narrows, which causes acute coronary insufficiency and sudden death, including in patients after myotomy.

During coronary angiography, it is seen that part of the coronary artery is narrowed in systole, but 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 an increase in lactate production in the regional vein. Ischemia usually occurs when there is a long, thick muscle bridge that occludes the artery and relaxes unusually slowly, so 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 only in cases of ventricular hypertrophy, especially in hypertrophic cardiomyopathy.

Aneurysm of the coronary artery

It was first described in 1812. It belongs to extremely rare anomalies. Only one in five coronary artery aneurysms are congenital. Acquired aneurysm can occur in children due to Kawasaki disease, previous endocarditis, nodular coronary disease, and in adults - as a result of the development of atherosclerosis, syphilitic lesions of the coronary arteries, or against the background of a congenital coronary artery fistula. A coronary artery aneurysm can also result from myocardial infarction. congenital aneurysm occurs due to a violation of the structure of the mesothelium of the vessel or a deficiency of normal protein fibers of the connective tissue. Both the right and left coronary arteries can be subjected to aneurysmal expansion, in very rare cases both arteries can be affected, and multiple aneurysms of the coronary arteries are even more rarely diagnosed. Described combined vice in the form of TMA with an aneurysm of the coronary arteries. All types of aneurysms of the coronary arteries can either be asymptomatic until they rupture, or lead to the development of ischemia or myocardial infarction. Cases of thrombosis of an aneurysm of a coronary artery are described.

Surgery

Indications for surgery are signs of myocardial ischemia or accidental detection of an aneurysm large sizes. The operation consists in resection of the aneurysm and the imposition of a coronary artery bypass graft or ligation of the aneurysm in its initial and final sections with the imposition of a coronary artery bypass graft below the aneurysm. Indications for surgical intervention can occur in both congenital and acquired aneurysms of the coronary artery. An aneurysm due to Kawasaki disease rarely requires surgical intervention, except in cases of threatened aneurysm rupture or thrombosis.

The type of blood supply to the heart is understood as 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 sulci - 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 a posterior interventricular branch, which runs along the posterior interventricular sulcus towards the apex of the heart and supplies blood to the posterior part of the interventricular septum. Another anatomical feature is described to determine the predominant type of blood supply. It is noted that the branch to the atrioventricular node always departs from the predominant artery, i.e. from an artery that has highest value in the supply of blood from 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, the right ventricle, the posterior part of the interventricular septum, and the 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 diaphragmatic 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 contribute approximately equally 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 the coronary arteries in the heart. Since the mass of the left ventricle is much larger than the right one, and the left coronary artery always supplies blood to 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 predominant in all normal hearts. Thus, in any type of coronary blood supply, the left coronary artery is predominant in the physiological sense.

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

For topical indication of lesions, it is proposed to divide the coronary bed into segments.

Dotted lines in this scheme highlight the segments of the coronary arteries.

So in the left coronary artery in 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. medium - from 1DV to 2DV.
3. distal - after the discharge of 2DV.

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

1. proximal - from the mouth of the OB to 1 VTK.
2. medium - from 1 VTK to 3 VTK.
3. distal - after the discharge of 3 VTC.

Right coronary artery divided into the following main segments:

1. proximal - from the mouth to 1 wok
2. medium - from 1 wok to the sharp edge of the heart
3. distal - up to the RCA bifurcation to the posterior descending and posterolateral arteries.

Coronary arteries of the heart

In this section, you will get acquainted with the anatomical location of the coronary vessels of the heart. To learn about the anatomy and physiology of the heart vascular system You need to visit the section "Heart Diseases".

• 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 starts from the left posterior sinus of Wilsalva, goes down to the anterior longitudinal groove, leaving the pulmonary artery to the right of itself, and the left atrium and the ear surrounded by adipose tissue, which usually covers it, to the left. 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 branch (OB), or arteries, are of the greatest importance for pathology.

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

Along the anterior longitudinal cardiac sulcus, it goes to the region of the apex of the heart, usually reaches it, sometimes bends over it and passes to the back 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 blunt edge; in addition, numerous septal branches depart from it, perforating the myocardium and branching in the anterior 2/3 of the interventricular septum. Lateral branches feed the anterior wall of the left ventricle and give branches to the anterior papillary muscle of the left ventricle. The superior septal artery gives a branch to the anterior wall of the right ventricle and sometimes to the anterior papillary muscle of the right ventricle.

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

The envelope 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 right one, passes in the transverse groove, reaches the blunt edge of the heart, goes around it, passes to back wall of the left ventricle, sometimes reaches the posterior interventricular sulcus and, in the form of a posterior descending artery, goes to the apex. Numerous branches depart from it to the anterior and posterior papillary muscles, the anterior and posterior walls of the left ventricle. One of the arteries that feed 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, goes around the heart along the right atrioventricular sulcus, passes to the posterior wall, reaches the posterior longitudinal sulcus, 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, partly to anterior section septum, both papillary muscles of the right ventricle, the posterior wall of the right ventricle and back section interventricular septum; the second branch also departs from it to the sinoauricular node.

There are three main types of myocardial blood supply: middle, left and right. This subdivision 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 regions is quite stable and not subject to significant deviations.

At middle 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 system of the left coronary artery. The right ventricle, including both right papillary muscles and the posterior 1/2-1/3 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 partly 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 groove and ends here in the form of the posterior descending artery, giving part of the branches to the posterior surface of the right ventricle .

Right type observed with a weak development of the circumflex branch, which either ends without reaching the obtuse edge, or passes into the coronary artery of the obtuse edge, not spreading to the posterior surface of the left ventricle. In such cases, the right coronary artery, after leaving the posterior descending artery, usually gives a few 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.

Myocardial blood supply is carried out directly :

a) capillaries lying between muscle fibers, braiding them and receiving blood from the system of coronary arteries through arterioles;

b) a rich network of myocardial sinusoids;

c) Viessant-Tebesia vessels.

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

Outflow occurs through the veins, which are collected in the coronary sinus

Venous blood in the coronary system is collected 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 back 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 ischemic disease, so the 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 they are of small diameter. However, their number and magnitude increase not only in coronary atherosclerosis, but also in valvular heart disease. Age and gender by themselves have no effect on the presence and degree of development of anastomoses.

Heart (cor)

The circulatory system is made up of a large number of elastic vessels. different structure and sizes - arteries, capillaries, veins. In the center circulatory system the heart is located - a living delivery-suction pump.

The structure of the heart. The heart is the central apparatus of the vascular system, highly capable of automatic action. In humans, it is located in chest behind sternum, for the most part (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) up, back and to the right, and its narrower cone-shaped part (top) forward, down and to the 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, not reaching the mid-clavicular line (passing through the nipple in men) by 1 cm. The tip 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 - crescent ligament; 8 - stomach; 9 - nameless artery; 10 - subclavian artery; 11 - common carotid arteries; 12 - thyroid; 13 — thyroid cartilage; 14 - superior vena cava

In shape (Fig. 223), the heart resembles a cone, with its base up and its top down. Large blood vessels enter and leave 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). The average size of the heart: length 13 cm, width 10 cm, thickness (anteroposterior diameter) 7-8 cm. In terms of volume, 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 - nameless artery; 2 - superior vena cava; 3 - ascending aorta; 4 — a coronal furrow with the right coronal artery; 5 - right ear; 6 - right atrium; 7 - right ventricle; 8 - apex of the heart; 9 - left ventricle; 10 - anterior longitudinal furrow; 11 - left ear; 12 - left pulmonary veins; 13 - pulmonary artery; 14 - aortic arch; 15 - left subclavian artery; 16 - left common 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 functionally important layer is the muscular layer, the myocardium. The muscle tissue of the heart differs from skeletal muscle; it also has transverse banding, but the ratio of cell fibers is different than in the muscles of the skeleton. 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 transitional fibers that make up the predominant mass. The outer longitudinal fibers, deepening obliquely, gradually pass into the annular, which also obliquely gradually pass into the internal longitudinal; the papillary muscles of the valves are also formed from the latter. On the very surface of the ventricles lie fibers covering both ventricles together. Such a complex course of muscle bundles provides the most full reduction and emptying of the cavities of the heart. muscle layer the walls of the ventricles, especially in the left, which drives the blood in a large circle, are much thicker. The muscle fibers that form the walls of the ventricles are assembled from the inside into numerous bundles, which are located in different directions, forming fleshy crossbars (trabeculae) and muscle protrusions - papillary muscles; tendon cords go from them to the free edge of the valves, which stretch when the ventricles contract and do not allow the valves to open in the atrial cavity under the pressure of blood.

Rice. 224. The course of the muscle fibers of the heart (semi-schematically)

The muscle layer of the walls of the atria is thin, since they have a small load - they only drive blood into the ventricles. Superficial muscle pins, facing inside the atrial cavity, form the pectinate muscles.

WITH outer surface two grooves are noticeable on the heart (Fig. 225, 226): longitudinal, covering the heart in front and behind, and transverse (coronal), located annularly; along them are the own arteries and veins of the heart. These grooves inside correspond to the 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 hearts. The transverse septum divides each of these halves into an upper chamber - the atrium (atrium) and a lower one - the ventricle (ventriculus). Thus, two non-communicating atria and two separate ventricles are obtained. The superior vena cava, inferior vena cava and coronary sinus flow into the right atrium; the pulmonary artery departs from the right ventricle. The right and left pulmonary veins flow into the left atrium; the aorta departs 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 - unnamed artery

Rice. 226. Heart (rear view). 1 - aortic arch; 2 - left subclavian artery; 3 - left common carotid artery; 4 - unpaired 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 drain 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 looks like 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 atrial wall form parallel muscle rollers.

The left heart auricle (auricula cordis sinistra) departs from the anterior wall of the left atrium, in the cavity of which there are also muscle rollers. The walls in the left atrium are smoother from the inside than in the right.

The inner shell (Fig. 227), lining the inside of the heart cavity, is called the endocardium (endocardium); it is covered with a layer of endothelium (a derivative of the mesenchyme), which also extends to the inner lining of the vessels extending from the heart. On 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 with endothelium on both sides - these are the heart valves (Fig. 228) that close the atrioventricular openings. In the right atrioventricular opening 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 flap valves open during atrial systole only towards the ventricles.

Rice. 227. The heart of an adult with the ventricles opened in front. 1 - ascending aorta; 2 - arterial ligament (overgrown ductus arteriosus); 3 - pulmonary artery; 4 - semilunar valves of the pulmonary artery; 5 - left ear of the heart; 6 - anterior cusp of a bicuspid valve; 7 - anterior papillary muscle; 8 — a back leaflet of the bicuspid valve; 9 - tendon threads; 10 - posterior papillary muscle; 11 - left ventricle of the heart; 12 - right ventricle of the heart; 13 - rear cusp of the tricuspid valve; 14 - medial cusp of the tricuspid valve; 15 - right atrium; 16 - anterior cusp of the tricuspid valve, 17 - arterial cone; 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 site 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 hole. In their form, these valves are called semilunar (valvulae semilunares). They open only upward towards the vessels during ventricular contraction. During the relaxation (expansion) of the ventricles, they automatically close and do not allow the reverse flow of blood from the vessels to the ventricles; when the ventricles are compressed, they reopen with a current of ejected blood. The semilunar valves are devoid of musculature.

It can be seen from the foregoing that in humans, as in other mammals, the heart has four valve systems: two of them, valvular, separate the ventricles from the atria, and two, semilunar, separate the ventricles from the arterial system. There are no valves at the place 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, partly acting as a valve or damper. In addition, there are thickenings of annular muscle fibers of the adjacent part of the atrial wall. These thickenings muscle tissue during atrial contraction, the mouths of the veins are compressed and this prevents the reverse flow of blood into the veins, so that it enters only the ventricles.

In an organ that performs such a big job as the heart, supporting 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 aortic root and the membranous part of the ventricular septum; they all consist of bundles of collagen fibrils with an admixture of elastic fibers.

The heart valves are composed of dense and elastic connective tissue (doubling of the endocardium - duplication). When the ventricles contract, the cusp valves, under pressure from the blood in the cavity of the ventricles, straighten out, like stretched sails, and touch so tightly that they completely close the openings between the atrial cavities and the ventricular cavities. At this time, the tendon threads mentioned above support them and prevent them from turning inside out. Therefore, blood from the ventricles cannot get back into the atria; under the pressure of the contracting ventricles, it is pushed out of the left ventricle into the aorta, and from the right into the pulmonary artery. Thus, all the valves of the heart open only in one direction - in the direction of blood flow.

The size of the cavities of the heart, depending on the degree of filling with blood and the intensity of its work, varies. So, the capacity of the right atrium ranges from 110-185 cm 3, the right ventricle - from 160 to 230 cm 3, the left atrium - from 100 to 130 cm 3 and the left ventricle - from 143 to 212 cm 3.

The heart is covered with thin serosa, forming two sheets, passing one into the other at the place of departure from the heart of large vessels. The inner, or visceral, leaf of this sac, directly covering the heart and tightly soldered to it, is called the epicardium (epieardium), the outer, or parietal, leaf is called the pericardium (pericardium). The parietal sheet forms a bag covering the heart - this is a heart bag, or a heart shirt. The pericardium is adjacent to the sheets of the mediastinal pleura from the sides, adheres to the tendon center of the diaphragm from below, and is attached in front by connective tissue fibers to the posterior surface of the sternum. A slit-like hermetically closed cavity is formed between both sheets of the heart sac around the heart, always containing a certain amount (about 20 g) of serous fluid. The pericardium insulates the heart from its surrounding organs, and the fluid moistens the surface of the heart, reducing friction and making its movements slip during contractions. In addition, strong fibrous tissue the pericardium limits and prevents excessive stretching of the muscle fibers of the heart; if there were no pericardium, which anatomically limits the volume of the heart, it would be in danger of overstretching, especially during periods of its most intense and unusual activity.

Incoming and outgoing vessels of the heart. The superior and inferior vena cava join the right atrium. At the confluence of these veins, a wave of contraction of the heart muscle arises, quickly covering both atria and then passing 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 from the walls of the heart itself. The opening of the sinus closes with a small fold (thebesian valve).

Four years of intravenous veins flow into the left atrium. The largest artery in the body, the aorta, emerges from the left ventricle. It goes first to the right and up, then, bending back and to the left, it spreads through 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 towards both lungs.

In total, the heart has seven input - venous - openings and two output - arterial - openings.

Circles of blood circulation(Fig. 229). Due to the long and complex evolution of the development of the circulatory organs, a certain system of supplying the body with blood has been established, which is characteristic of humans and all mammals. As a rule, blood moves within a closed system of tubes, which includes a constantly acting powerful muscular organ- heart. The heart, as a result of its historical automatism and regulation by the central nervous system, continuously and rhythmically drives blood throughout the body.

Rice. 229. Scheme of blood circulation and lymph circulation. Vessels through which flows arterial blood; blue - vessels with venous blood; purple color shows the portal vein system; 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 through the aorta first enters large arteries, which gradually branch into smaller ones and then pass into arterioles and capillaries. Through 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 in return receives carbon dioxide and cellular metabolic products. Changing in its composition, the blood further becomes unsuitable for maintaining respiration and nutrition of cells, it turns from arterial to venous. 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.

Passed from the right atrium to the right ventricle venous blood, the heart sends through the pulmonary artery to the lungs, where it is released from carbon dioxide and saturated with oxygen in the smallest network of pulmonary capillaries, 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 comes to supply body tissues. The circulation of blood along the way from the heart through the lungs and back is a small circle of blood circulation. The heart not only performs the work of a motor, but also acts as an apparatus that controls the movement of blood. Switching blood from one circle 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 (1628) blood circulation, and Malpighi (1661), who established blood circulation in capillaries.

Blood supply to the heart(see fig. 226). The heart, carrying out an exceptionally important service in the body and doing a tremendous job, itself needs abundant food. This is an organ that is in an active state throughout a person's life and never has a rest period that would last more than 0.4 seconds. Naturally, this organ must be supplied with a particularly abundant amount of blood. Therefore, its blood supply is arranged in such a way that it fully ensures the inflow and outflow of blood.

The heart muscle receives blood before all other organs through two coronary (coronary) arteries (a. eoronaria cordis dextra et sinistra), extending directly from the aorta just above the semilunar valves. About 5-10% of all blood ejected into the aorta enters the abundantly developed network of coronary vessels of the heart, even at rest. The right coronary artery runs along the transverse groove to the right to 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 conducting system of the heart - the Ashof-Tavar node, the bundle of His (see below). The left coronary artery divides into two branches. One of them goes along the longitudinal groove to the apex of the heart, giving numerous lateral branches, the other goes 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 a large number of branches, widely aiastomosing among themselves and crumbling into a very dense network of capillaries, penetrating everywhere, into all parts of the organ. There are 2 times more (thicker) capillaries in the heart than in 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 independently directly into the right atrium. All other veins that collect blood from individual sections heart 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 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 pierced by the richest network lymphatic vessels. The entire space between muscle fibers and blood vessels The heart is a dense network of lymphatic vessels and fissures. 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 what has been said, it can be seen that the heart has its own third circle of blood circulation. Thus, the coronary circle is included in parallel to the entire systemic circulation.

The coronary circulation, in addition to nourishing the heart, also has a protective value for the body, greatly mitigating harmful effects excessively high blood pressure with 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 path.

Innervation of the heart(Fig. 230). Contractions of the heart are made 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. IP Pavlov said that "four centrifugal nerves control the activity of the heart: 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 (plexus cardiacus) on the heart, the fibers of which spread along with the coronary vessels of the heart.

Rice. 230. Conducting system of the heart. Schematic diagram of the conduction system in the human heart. 1 - Kis-Flak node; 2 - Ashof-Tavar node; 3 - bundle of His; 4 - legs of the bundle of His; 5 - a network of Purkinje fibers; 6 - superior vena cava; 7 - inferior vena cava; 8 - atrium; 9 - ventricles

The coordination of the activity of the parts of the heart, atria, ventricles, the sequence of contractions, relaxations are 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 a sinus node (Kis-Flak node), which is connected by a bundle of the same fibers to another node (Ashof-Tavar node), located on the border between the right atrium and ventricle. A large bundle of fibers (the bundle of His) departs from this node, which descends in the septum of the ventricles, dividing into two legs, and then crumbles in the walls of the right and left ventricles under the epicardium, ending in the papillary muscles.

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

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

Blood, thanks to the "internal motor" - the heart, circulates through the body, saturating each of its cells with nutrients and oxygen. And how does the heart itself receive nourishment? Where does it draw reserves and strength for work? And do you know about the so-called third circle of blood circulation or cardiac? For a better understanding of the anatomy of the vessels that supply the heart, let's look at the main anatomical structures that are usually distinguished in the central organ of the cardiovascular system.

1 External device of the human "motor"

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

1. coronal furrow,
2. anterior interventricular,
3. Posterior interventricular.

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

The posterior interventricular sulcus is the receptacle for the interventricular branch of the right coronary artery, the middle cardiac vein. From the abundance of numerous medical terminology, the head can go round: furrows, arteries, veins, branches ... Still, because we are analyzing the structure and blood supply of the most important human organ- hearts. If it had been arranged in a simpler way, would it have been able to perform such a complex and responsible job? Therefore, we will not give up halfway, and analyze in detail the anatomy of the vessels of the heart.

2 3rd or cardiac 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 people? Not at all! The third circle, figuratively named, refers to the blood vessels that fill and “serve” the heart itself. It deserves personal vessels, doesn'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 cardiac veins that merge 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, envelop it like a real crown, a crown. Therefore, the arteries and veins are called coronary or coronary. Note: These are synonymous terms. So what are the most important arteries and veins that the heart has at its disposal? What is the classification of the coronary arteries?

3 Major arteries

The right coronary artery and the left coronary artery are two whales that deliver oxygen and nutrients. They have branches and branches, which we will discuss next. In the meantime, let us understand that the right coronary artery is responsible for the blood supply to the right heart chambers, the walls of the right ventricle and the posterior wall of the left ventricle, and the left coronary artery supplies the left heart sections.

The right coronary artery goes around the heart along the coronary sulcus on the right, gives 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 groove, but on the other, opposite side - in front of the left atrium. It is divided into two major branches - the anterior interventricular (anterior descending artery) and circumflex artery.

The path of the anterior interventricular branch runs in the depression of the same name, to the apex of the heart, where our branch meets and merges with a 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 combines with the right coronary. Thus, nature created on the surface of the human "motor" an arterial ring of coronary vessels in a horizontal plane.

This is an adaptive element, in case a vascular accident suddenly occurs in the body and blood circulation deteriorates sharply, 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 go in another heart 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 heart 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 features bookmarks of the vessels of the heart and their functioning in each person. Depending on the prevailing distribution of one of the coronary arteries on the posterior heart wall, there are:

1. Legal type. With this type of blood supply to the heart, the left ventricle (the back surface of the heart) is filled with blood mainly due to 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 prevails in the blood supply (in 10% of cases).
3. Uniform type. With an approximately equivalent "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 pour blood into the sinus are:

1. Big. Takes venous blood from the anterior surface of the two lower chambers, lies in the interventricular anterior sulcus. The vein starts at the top.
2. Average. It also originates at the top, but runs along the back furrow.
3. Small. It can flow into the middle, 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. So, in the most simplified way, you can imagine how the blood supply to the heart occurs, 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 a separate blood circulation can be maintained. The most important cardiac arteries are the right and left coronary arteries, and the veins are large, medium, small, and anterior.

6 Diagnosis of coronary vessels

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

Photographs and video recording of the filling of vessels with a substance are made. The results allow the doctor to make a conclusion about the patency of the vessels, the presence of pathology in them, to assess the prospect of treatment and the possibility of recovery. Also, diagnostic methods for studying coronary vessels include MSCT - angiography, ultrasonography 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, in connection with which they are called coronary arteries. The right coronary artery begins at the level of the right sinus of the aorta, and the left coronary artery - 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 let blood flow to the heart. With relaxation (diastole) of the ventricles, the sinuses fill with blood, blocking its path from the aorta back to the left ventricle, and at the same time open the access of blood to the vessels of the heart.

Right coronary artery

It leaves to the right under the ear of the right atrium, lies in the coronary sulcus, goes around the right pulmonary surface of the heart, then follows its posterior surface to the left, where it anastomoses with its end 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 sulcus of the same name towards the apex of the heart. The branches of the right coronary artery supply 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 cardiac conduction system.

Left coronary artery

A little thicker than the right. 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, goes around the heart on the left, located in its coronary sulcus, where it anastomoses with the right coronary artery on the posterior surface of the organ. The anterior interventricular branch follows the sulcus of the same name towards the apex of the heart. In the region 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. The 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 sulcus, and a longitudinal one, the vessels of which are located in the anterior and posterior interventricular sulci.

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 the highest, microvessels anastomosing with each other repeat the course of the bundles of muscle fibers of its layers.

There are various options for the distribution of branches of the coronary arteries, which are called types of blood supply to the heart. The main ones are as follows: 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 medium, 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.

Variants and anomalies of the position and branching of the coronary arteries are possible. They are manifested in changes in the places of origin and the number of coronary arteries. So, the latter can depart from the aopta 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 (additional) arteries go to the heart (especially to the pericardium). These can be mediastinal-pericardial branches (upper, middle and lower) of the internal thoracic artery, branches of the pericardial phrenic artery, branches extending from the concave surface of the aortic arches, etc.