The heart is located in the chest cavity. Position of the heart in the chest

The heart is the main organ of the human body. It is a muscular organ, hollow inside and cone-shaped. In newborns, the heart weighs about thirty grams, and in an adult it weighs about three hundred.

The topography of the heart is as follows: it is located in the chest cavity, and one third of it is located on the right side of the mediastinum, and two thirds on the left. The base of the organ is directed upward and somewhat posteriorly, and the narrow part, that is, the apex, is directed downward, to the left and anteriorly.

Organ boundaries

The boundaries of the heart allow us to determine the location of the organ. There are several of them:

1. Upper. It corresponds to the cartilage of the third rib.
2. Bottom. This border connects the right side to the apex.
3. The top. located in the fifth intercostal space, towards the left midclavicular straight line.
4. Right. Between the third and fifth ribs, a couple of centimeters to the right of the edge of the sternum.
5. Left. The topography of the heart at this border has its own characteristics. It connects the apex with the upper border, and itself runs along which faces the left lung.

According to topography, the heart is located behind and just below half of the sternum. The largest vessels are located behind, in the upper part.

Topography changes

The topography and structure of the heart in humans changes with age. In childhood, the organ makes two revolutions around its axis. The boundaries of the heart change during breathing and depending on the position of the body. So, when lying on the left side and bending over, the heart approaches the chest wall. When a person stands, it is located lower than when he lies. Because of this feature it shifts. According to anatomy, the topography of the heart also changes as a result of respiratory movements. So, as you inhale, the organ moves further away from the chest, and as you exhale, it returns back.

Changes in the function, structure, and topography of the heart are observed in different phases of cardiac activity. These indicators depend on gender, age, as well as on the individual characteristics of the body: the location of the digestive organs.

Structure of the heart

The heart has an apex and a base. The latter faces up, to the right and back. At the back, the base is formed by the atria, and in front - by the pulmonary trunk and a large artery - the aorta.

The top of the organ faces down, forward and to the left. According to the topography of the heart, it reaches the fifth intercostal space. The apex is usually located at a distance of eight centimeters from the mediastinum.

The walls of the organ have several layers:

1. Endocardium.
2. Myocardium.
3. Epicardium.
4. Pericardium.

The endocardium lines the organ from the inside. This tissue forms the valves.

The myocardium is the heart muscle that contracts involuntarily. The ventricles and atria also consist of muscles, and in the former the muscles are more developed. The superficial layer of the atrium muscles consists of longitudinal and circular fibers. They are independent for each atrium. And in the ventricles there are the following layers of muscle tissue: deep, superficial and middle circular. From the deepest part, fleshy bridges and papillary muscles are formed.

The epicardium is epithelial cells that cover the outer surface of the organ and the nearest vessels: the aorta, vein, and pulmonary trunk.

The pericardium is the outer layer of the pericardial sac. Between the leaves there is a slit-like formation - the pericardial cavity.

Holes

The heart has several holes and chambers. The organ has a longitudinal septum that divides it into two parts: left and right. At the top of each part are the atria, and at the bottom are the ventricles. There are openings between the atria and ventricles.

The first of them have some protrusion, which forms the cardiac ear. The walls of the atria have different thicknesses: the left one is more developed than the right one.

Inside the ventricles there are papillary muscles. Moreover, there are three of them on the left, and two on the right.

Fluid enters the right atrium from the superior and inferior pudendal veins and the veins of the sinus of the heart. Four lead to the left. From the right ventricle, the aorta leaves and from the left.

Valves

The heart has tricuspid and bicuspid valves that close the gastroatrial openings. The absence of reverse blood flow and eversion of the walls is ensured by tendon threads passing from the edge of the valves to the papillary muscles.

The bicuspid or mitral valve closes the left ventricular orifice. Tricuspid - right ventricular-atrial opening.

In addition, in the heart there is one that closes the opening of the aorta, and the other that closes the pulmonary trunk. Valve defects are defined as heart disease.

Circulation circles

In the human body there are several circles of blood circulation. Let's look at them:

1. The great circle (BC) starts from the left ventricle and ends at the right atrium. Through it, blood flows through the aorta, then through the arteries, which diverge into precapillaries. After this, the blood enters the capillaries, and from there to the tissues and organs. In these small vessels, nutrients are exchanged between tissue cells and blood. After this, the reverse flow of blood begins. From the capillaries it enters the postcapillaries. They form venules from which venous blood enters the veins. Along them it approaches the heart, where the vascular beds converge into the vena cava and enter the right atrium. This is how the blood supply to all organs and tissues occurs.
2. The pulmonary circle (PV) starts from the right ventricle and ends at the left atrium. Its origin is the pulmonary trunk, which divides into a pair of pulmonary arteries. Venous blood flows through them. It enters the lungs and is enriched with oxygen, turning into an arterial one. The blood then collects in the pulmonary veins and flows into the left atrium. MKK is intended to enrich the blood with oxygen.
3. There is also a coronal circle. It starts from the aortic bulb and the right coronary artery, passes through the capillary network of the heart and returns through the venules and coronary veins, first to the coronary sinus and then to the right atrium. This circle supplies nutrients to the heart.

The heart, as you can see, is a complex organ that has its own circulation. Its boundaries change, and the heart itself changes its angle of inclination with age, turning around its axis twice.

The heart is a hollow muscular organ shaped like a cone, 250-360 g, in newborns - 25 g.

Located in the chest cavity, behind the sternum, in the anterior mediastinum: 2/3 in the left half, 1/3 in the right. The wide base is directed upward and backward, and the narrowed part with its apex is directed downward, anteriorly and to the left. The heart has 2 surfaces: the anterior sternocostal and the inferior diaphragmatic.

Position of the heart in the chest (the pericardium is opened). 1 - left subclavian artery (a. subclavia sinistra); 2 - left common carotid artery (a. carotis communis sinistra); 3 - aortic arch (arcus aortae); 4 - pulmonary trunk (truncus pulmonalis); 5 - left ventricle (ventriculus sinister); 6 - apex of the heart (apex cordis); 7 - right ventricle (ventriculus dexter); 8 - right atrium (atrium dextrum); 9 - pericardium (pericardium); 10 - superior vena cava (v. cava superior); 11 - brachiocephalic trunk (truncus brachiocephalicus); 12 - right subclavian artery (a. subclavia dextra)

StructureWalls heart 3 layers: internal ENDOCARDIUM (flattened thin smooth endothelium) - lining the inside, valves are formed from it; MYOCARDIUM (cardiac striated muscle tissue - involuntary contractions). The muscles of the ventricles are better developed than the atria. The superficial layer of the atrium musculature consists of transverse (circular) fibers common to both atria, and the deep layer of vertically (longitudinally) located fibers, independent for each atrium. The ventricles have 3 layers of muscles: the superficial and deep are common to the ventricles, the middle circular layer is separate for each ventricle. From the deep, fleshy crossbars and papillary muscles are formed. Muscle bundles are poor in myofibrils, but rich in sarcoplasm (lighter), along which there is a plexus of soft nerve fibers and nerve cells - the conduction system of the heart. It forms nodes and bundles in the atria and ventricles. EPIKARDIUM (epithelial cells, inner layer of the pericardial serous membrane) - covers the outer surface and surrounding areas of the aorta, pulmonary trunk, and vena cava. PERICARDIUM - the outer layer of the pericardial sac. Between the inner layer of the pericardium (epicardium) and the outer layer there is a slit-like pericardial cavity.

Heart; longitudinal section. 1 - superior vena cava (v. cava superior); 2 - right atrium (atrium dextrum); 3 - right atrioventricular valve (valva atrioventricularis dextra); 4 - right ventricle (ventriculus dexter); 5 - interventricular septum (septum interventriculare); 6 - left ventricle (ventriculus sinister); 7 - papillary muscles (mm. papillares); 8 - tendon chords (chordae tendineae); 9 - left atrioventricular valve (valva atrioventricularis sinistra); 10 - left atrium (atrium sinistrum); 11 - pulmonary veins (vv. pulmonales); 12 - aortic arch (arcus aortae)

Muscular layer of the heart (according to R. D. Sinelnikov) . 1 - vv. pulmonales; 2 - auricula sinistra; 3 - outer muscular layer of the left ventricle; 4 - middle muscle layer; 5 - deep muscle layer; 6 - sulcus interventricularis anterior; 7 - valva trunci pulmonalis; 8 - valva aortae; 9 - atrium dextrum; 10 - v.cava superior

Right half of the heart (opened)

On the anterior chest wall the boundaries of the heart are projected:

The upper border is the upper edge of the cartilages of the 3rd pair of ribs.

The left border is along an arc from the cartilage of the 3rd left rib to the projection of the apex.

The apex is in the left fifth intercostal space 1-2 cm medial to the left midclavicular line.

The right border is 2 cm to the right of the right edge of the sternum.

Lower from the upper edge of the cartilage of the 5th right rib to the projection of the apex.

In newborns, the heart is almost entirely on the left and lies horizontally.

In children under one year of age, the apex is 1 cm lateral to the left midclavicular line, in the 4th intercostal space.

Projection on the anterior surface of the chest wall of the heart, leaflet and semilunar valves . 1 - projection of the pulmonary trunk; 2 - projection of the left atrioventricular (bicuspid) valve; 3 - apex of the heart; 4 - projection of the right atrioventricular (tricuspid) valve; 5 - projection of the semilunar valve of the aorta. The arrows indicate the sites of auscultation of the left atrioventricular and aortic valves

Cameras, holes. The heart is divided into left and right halves by a longitudinal septum. At the top of each half there is an atrium, at the bottom - a ventricle. The atria communicate with the ventricles through the atrioventricular orifice. The atrial protrusions form the right and left atrial appendages. The walls of the left ventricle are thicker than the walls of the right (the myocardium is better developed). Inside the right ventricle there are 3 (usually) papillary muscles, in the left - 2. The right atrium receives blood from the superior (enters from above), inferior vena cava (posteriorly from below), veins of the coronary sinus of the heart (below the inferior vena cava). 4 pulmonary veins flow into the left one. The pulmonary trunk emerges from the right ventricle, and the aorta from the left.

Heart: A - front; B - behind

Heart valves(cusps from endocardial folds) close the atrioventricular openings. Right - 3-leaf, left - 2-leaf (mitral). The edges of the valves are connected by tendon threads to the papillary muscles (due to which they do not turn out and there is no reverse blood flow). Near the openings of the pulmonary trunk and aorta there are semilunar valves in the form of 3 pockets that open in the direction of blood flow. ↓ pressure in the ventricles, then blood flows into the pockets, the edges close → there is no blood flow back to the heart.

The heart is located in the chest cavity in such a way that 1/3 of its x-ray shadow is projected to the right of the midline of the body, and 2/3 to the left. The base of the heart is deviated posteriorly to the right, and the apex is deviated anteriorly and to the left. The most objective indicator characterizing the position of the heart is the angle of inclination of the heart. This angle is formed by the horizontal plane and the length of the heart. The length (long diameter of the heart - L) of the heart is understood as the distance from the point of intersection of the arcs along the right contour of the cardiovascular shadow to the point of intersection of the left ventricle with the left dome of the diaphragm (the upper limit of the norm is 15.5 cm). The length reflects the length of the left ventricle along with the atrium. It is customary to distinguish between an oblique position of the heart, in which the angle of inclination is from 43 to 48 degrees, a horizontal position, when the angle of inclination is less than 43 degrees, and a vertical position, in which the angle of inclination is more than 48 degrees.

The position of a normal heart changes depending on the constitution, age, gender, height of the domes of the diaphragm, changes in body position, the phase of breathing and the magnitude of intrathoracic pressure, the severity of acceleration phenomena, the tone of the muscles of the chest wall, etc.

In persons with a normosthenic constitution (axis inclination angle 45 0), as a rule, an oblique position of the heart is found, in asthenics - vertical (axis inclination angle more than 45 0), in picnics - horizontal (axis inclination angle less than 45 0). The oblique diameter of the heart (basal diameter) is the distance from the left atriovasal angle to the right cardiophrenic angle - normally no more than 11.2 cm. The oblique diameter reflects the base of the ventricles and the plane of the valves.

In newborns and young children (up to 7 years), the heart usually occupies a transverse position in the chest cavity, in contact with the diaphragm for a long distance; as the child grows, the depth of the chest gradually decreases, and the abdominal organs and diaphragm descend. In this regard, the axis of the heart changes, taking a more vertical position. Typically these changes are observed between 6 and 12 years of a child's life.

Starting from puberty, the dominant influence on the position of the heart is exerted by the intensity and proportionality of the growth of individual organs and constitutional factors. In adolescents, there is a clear tendency to change the axis of the heart towards a vertical position. U In adults with a normosthenic constitution, an oblique position of the heart is most common.

The volume of a healthy person's heart also varies significantly. In addition to constitutional features, age and gender differences, the volume is influenced by the amount of residual blood contained in the cavities of the heart, the minute volume of the pulmonary circulation and the functional state of the myocardium (the degree of physiological myocardial hypertrophy). The volume of the heart is significantly affected by changes in body position. Normally, in a vertical position of the body, the volume of the heart of an adult in the systole phase is on average 620 cm 3, in the diastole phase - 729 cm 3. In a horizontal position of the body, the volume of the heart increases and averages: in the systole phase - 610 cm 3, and in diastole - 915 cm 3. The volume of the heart is calculated using the following formula:

V=K x L x B x t, Where

K-coefficient equal to approximately 0.5 (taking into account the volumetric shape of the heart, equated to an ellipse),

t- deep heart diameter,

L- length of the heart,

B- oblique diameter.

There are three degrees of increase in heart volume:

I - volume ranges from 100% to 114% of the age norm

II - volume ranges from 114% to 180% of the age norm

III - heart volume exceeds 180% of the age norm

The question of the X-ray picture of a normal heart has been of interest from the very beginning of the development of X-ray cardiology, and to this day it has not lost its relevance due to the presence of a large number of normal variants and the influence of constitutional and age factors.

The heart (cor) is a hollow muscular organ that pumps blood into the arteries and receives blood from the veins. The weight of the heart in an adult is 240 - 330 grams, it is the size of a fist, and its shape is cone-shaped. The heart is located in the chest cavity, in the lower mediastinum. In front it is adjacent to the sternum and costal cartilages, on the sides it is in contact with the pleural sacs of the lungs, behind it is in contact with the esophagus and thoracic aorta, and below it is in contact with the diaphragm. In the chest cavity, the heart occupies an oblique position, with its upper expanded part (base) facing upward, back and to the right, and its lower narrowed part (apex) facing forward, down and to the left. In relation to the midline, the heart is located asymmetrically: almost 2/3 of it lies to the left, and 1/3 to the right of the midline. The position of the heart can change depending on the phases of the cardiac cycle, on the position of the body (standing or lying down), on the degree of filling of the stomach, as well as on the individual characteristics of the person.

Projection of the borders of the heart onto the chest

The upper border of the heart is located at the level of the upper edges of the third right and left costal cartilages.

The lower border goes from the lower edge of the body of the sternum and the cartilage of the right rib to the apex of the heart.

The apex of the heart is located in the left intercostal space 1.5 cm medially from the midclavicular line.

The left border of the heart looks like a convex line running from top to bottom in an oblique direction: from the upper edge of the third (left) rib to the apex of the heart.

The heart, surrounded by the pericardium, is located in the lower part of the anterior mediastinum and, with the exception of the base, where it is connected to large vessels, can move freely in the pericardial cavity.

The sternocostal (anterior) surface of the heart faces partly to the sternum and costal cartilages, partly to the mediostinal pleura. The sternocostal surface consists of the anterior surfaces of the right atrium, right auricle, superior vena cava, pulmonary trunk, right and left ventricles, as well as the apex of the heart and the apex of the left auricle.

The diaphragmatic (lower) surface of the heart in the upper sections faces the esophagus and thoracic aorta, and in the lower sections it is adjacent to the diaphragm. The upper sections constitute the posterior surfaces of predominantly the left and partly the right atria, and the lower sections constitute the lower surfaces of the right and left ventricles and partly the atria.

The lower contour of the heart, formed by the right ventricle, faces the diaphragm, and the left pulmonary (lateral) surface is formed by the left ventricle and faces the left lung (Fig. , , , ). The base of the heart, formed by the left and partly right atria, faces the spinal column, the apex of the heart, formed by the left ventricle, is directed anteriorly and is projected onto the anterior surface of the chest in the area of ​​the left fifth intercostal space, 1.5 cm inward from a line drawn through the middle of the left collarbones, - left mamillary (midclavicular) line, linea medioclavicularis sinistra(rice. ).

The right contour of the heart is formed by the outer, right, edge of the right atrium facing the right lung and higher by the superior vena cava.

The left border of the heart is the left ventricle, facing the left lung, higher is the left auricle, and even higher is the pulmonary trunk.

The heart is located behind the lower half of the sternum, and large vessels (aorta and pulmonary trunk) are located behind its upper half (see Fig.).

In relation to anterior midline, linea mediana anterior, the heart is located asymmetrically: almost 2/3 of it lies to the left and about 1/3 to the right of this line.

The longitudinal axis of the heart, running from the base to the apex, forms an angle reaching 40° with the sagittal and frontal planes of the body. The longitudinal axis of the heart itself is directed from top to bottom, from right to left and from back to front. The heart, in addition, is somewhat rotated around its axis from right to left, so a significant part of the right heart is located more anteriorly, and most of the left heart is located more posteriorly, as a result of which the anterior surface of the right ventricle is adjacent to the chest wall closer than all other parts of the heart. The right edge of the heart, serving as its lower border, reaches the angle formed by the chest wall and the diaphragm right costophrenic sinus, recessus costodiaphragmatica dexter, the left atrium of all the cavities of the heart occupies the most posterior position.

To the right of the median plane of the body are the right atrium with both vena cava, a small part of the right ventricle and the left atrium; to the left of it is the left ventricle, most of the right ventricle with the pulmonary trunk and most of the left atrium with the appendage; the ascending aorta occupies a position to the left and right of the anterior midline.

The position of the heart and its parts in a person changes depending on the position of the body and respiratory movements. So, in a position on the left side or when tilted anteriorly, the heart is adjacent to the chest wall; in a standing position, the heart is located lower than in a lying position, so that the impulse of the apex of the heart moves slightly; When you inhale, the heart is further away from the chest wall than when you exhale.

The position of the heart changes depending on the phases of cardiac activity, age, gender and individual characteristics (height of the diaphragm), on the degree of filling of the stomach, small and large intestine.

Projection of the borders of the heart onto the anterior wall of the chest(see fig. , , ). Right border the heart has the appearance of a slightly convex line, 1.5-2.0 cm from the right edge of the sternum, descending from the upper edge of the cartilage of the 3rd rib to the junction of the cartilage of the 5th rib with the sternum.

Lower limit the heart is located at the level of the lower edge of the body of the sternum and is a slightly convex line running from the place of attachment of the cartilage of the right V rib to the sternum to a point located in the fifth intercostal space on the left side, 1.5 cm inward from the left mamillary (midclavicular) line .

Left border heart from a point located in the left second intercostal space, 2 cm outward from the edge of the sternum, passes in the form of a convex outward line obliquely down and to the left to a point located in the left fifth intercostal space 1.5-2.0 cm inward from the left midclavicular line .

Left ear projected in the left second intercostal space, moving away from the edge of the sternum; pulmonary trunk– on the cartilage of the second left rib at the place of its attachment to the sternum.

The projection of the heart onto the spinal column corresponds at the top to the level of the spinous process of the V thoracic vertebra, at the bottom to the level of the spinous process of the IX thoracic vertebra.

Projections of the atrioventricular openings and openings of the aorta and pulmonary trunk on the anterior wall of the chest (see Fig.). Left atrioventricular orifice(base of the left atrioventricular valve) is located to the left of the sternum in the third intercostal space; the sounds of this valve are heard at the apex of the heart.

Right atrioventricular orifice(base of the right atrioventricular valve) is located behind the right half of the sternum, on a line drawn from the point of connection with the sternum of the cartilage of the left III rib to the point of connection with the sternum of the cartilage of the right VI rib; the sounds of this valve are heard on the right at the level of the cartilages of the V-VI ribs and the adjacent area of ​​the sternum.

Aortic opening(aortic valve) lies behind the sternum, closer to its left edge, at the level of the third intercostal space; aortic valve sounds are heard on the right at the edge of the sternum in the second intercostal space.

Pulmonary opening(pulmonary valve) is located at the level of attachment of the cartilage of the left third rib to the sternum; the sounds of the pulmonary trunk are heard on the left at the edge of the sternum in the second intercostal space.

For innervation of the heart, see “Autonomic nervous system”, “Nerves of the heart”.