Segments of the lungs projection onto the chest. Pulmonary tuberculosis (focal and infiltrative). Educational video of the anatomy of the roots and segments of the lungs

Segments are morphofunctional elements of lung tissue, which include its own bronchus, artery and vein. They are surrounded by acini, the smallest functional unit of the pulmonary parenchyma (about 1.5 mm in diameter). The alveolar acini are ventilated by the bronchiole, the smallest branch of the bronchus. These structures ensure gas exchange between the surrounding air and blood capillaries.

Each of them has its own segmental structure.

Segments of the upper lobe of the right lung:

1. Apical (S1).
2. Rear (S2).
3. Front (S3).

There are 2 structural segments in the middle lobe:

1. External (S4).
2. Internal (S5).

There are 5 segments in the lower lobe of the right lung:

1. Upper (S6).
2. Lower internal (S7).
3. Inferoanterior (S8).
4. Lower external (S9).
5. Inferoposterior (S10).

The left lung has two lobes, so the structural structure of the pulmonary parenchyma is somewhat different. The middle lobe of the left lung consists of the following segments:

1. Upper reed (S4).
2. Lower reed (S5).

The lower lobe has 4-5 segments (different authors have different opinions):

1. Upper (S6).
2. Inferointernal (S7), which can be combined with inferoanterior (S8).
3. Lower external (S9).
4. Inferoposterior (S10).

It is more correct to distinguish 4 segments in the lower lobe of the left lung, since S7 and S8 have a common bronchus.

To summarize: the left lung consists of 9 segments, and the right lung has 10.

Topographic location of lung segments on a radiograph

X-ray, passing through the pulmonary parenchyma, does not clearly highlight topographical landmarks that allow localizing the segmental structure of the lungs. To learn how to determine the location of pathological dark spots in the lungs in an image, radiologists use markers.

The upper lobe is separated from the lower lobe (or middle lobe on the right) by an oblique interlobar fissure. It is not clearly visible on the x-ray. To highlight it, use the following guidelines:

1. In a direct image, it begins at the level of the spinous process of Th3 (3rd thoracic vertebra).
2. Runs horizontally along the outer part of the 4th rib.
3. Then it goes to the highest point of the diaphragm in the projection of its middle part.
4. In the lateral view, the horizontal pleura starts superiorly from Th3.
5. Passes through the root of the lung.
6. It ends at the highest point of the diaphragm.

The horizontal interlobar fissure separates the upper lobe from the middle lobe in the right lung. She goes through:

1. On a direct radiograph along the outer edge of the 4th rib - towards the root.
2. In the lateral projection, it starts from the root and goes horizontally to the sternum.

Topography of lung segments:

• apical (S1) runs along the 2nd rib to the scapular spine;
• posterior – from the middle of the shoulder blade to its upper edge;
• anterior - in front between the 2nd and 4th ribs;
• lateral (upper lingular) – between the 4th and 6th ribs along the anterior axillary line;
• medial (lower lingual) – between the 4th and 6th ribs closer to the sternum;
• upper basal (S6) – from the middle of the scapula to the lower angle along the paravertebral region;
• medial basal - from the 6th rib to the diaphragm between the midclavicular line and the sternum;
• anterior basal (S8) – between the interlobar fissure in front and the axillary lines in the back;
• lateral basal (S9) projects between the middle of the scapula and the posterior axillary line;
• posterior basal (S10) - from the lower angle of the scapula to the diaphragm between the scapular and paravertebral lines.

On the left, the segmental structure is insignificantly different, which allows the radiologist to quite accurately localize pathological shadows in the pulmonary parenchyma on photographs in frontal and lateral projections.

Rare features of lung topography

In some people, due to the abnormal position of the azygos vein, lobus venae azygos is formed. It should not be considered an abnormal lesion, but should be taken into account when reading chest x-rays.

In most people, the venae azygos flows into the superior vena cava medially from the mediastinal surface of the right lung, and therefore is not visible on radiographs.

When identifying the lobe of the azygos vein, it is obvious that in a person the place of entry of this vessel is shifted somewhat to the right in the projection of the upper lobe.

There are cases when the azygos vein is located below its normal position and compresses the esophagus, making swallowing difficult. In this case, difficulties arise during the passage of food - dysphagialusoria (“nature’s joke”). On an x-ray, the pathology is manifested by a marginal filling defect, which is considered a sign of cancer. In fact, after performing (CT), the diagnosis is excluded.

Other rare lung lobes:

1. The pericardium is formed by the irregular course of the medial part of the interlobar fissure.
2. Lingular - can be seen on photographs when the interlobar fissure is located in the projection of the 4th rib on the left. It is a morphological analogue of the middle lobe on the right in 1-2% of people.
3. Posterior - occurs when there is an additional gap separating the upper part of the lower lobe from its base. Occurs on both sides.

Every radiologist should know the topography and segmental structure of the lungs. Without this, it is impossible to read chest X-rays correctly.

Segment S1 (apical or apical) of the right lung. Refers to the upper lobe of the right lung. Topographically projected onto the chest along the anterior surface of the 2nd rib, through the apex of the lung to the spine of the scapula.

Segment S2 (posterior) of the right lung. Refers to the upper lobe of the right lung. Topographically projected onto the chest along the posterior surface paravertebrally from the upper edge of the scapula to its middle.

Segment S3 (anterior) of the right lung. Refers to the upper lobe of the right lung. Topographically, 2 to 4 ribs are projected onto the chest in front.

Segment S4 (lateral) of the right lung. Refers to the middle lobe of the right lung. Topographically projected onto the chest in the anterior axillary region between the 4th and 6th ribs.

Segment S5 (medial) of the right lung. Refers to the middle lobe of the right lung. Topographically projected onto the chest between the 4th and 6th ribs closer to the sternum.

Segment S6 (superior basal) of the right lung. Refers to the lower lobe of the right lung. Topographically projected onto the chest in the paravertebral region from the middle of the scapula to its lower angle.

Segment S7 (medial basal) of the right lung. Refers to the lower lobe of the right lung. Topographically localized on the inner surface of the right lung, located below the root of the right lung. It is projected onto the chest from the 6th rib to the diaphragm between the sternum and midclavicular lines.

Segment S8 (anterior basal) of the right lung. Refers to the lower lobe of the right lung. Topographically delimited anteriorly by the main interlobar groove, inferiorly by the diaphragm, and posteriorly by the posterior axillary line.

Segment S9 (lateral basal) of the right lung. Refers to the lower lobe of the right lung. Topographically projected onto the chest between the scapular and posterior axillary lines from the middle of the scapula to the diaphragm.

Segment S10 (posterior basal) of the right lung. Refers to the lower lobe of the right lung. Topographically projected onto the chest from the lower angle of the scapula to the diaphragm, delimited on the sides by the paravertebral and scapular lines.

Segment S1+2 (apical-posterior) of the left lung. It is a combination of C1 and C2 segments, which is due to the presence of a common bronchus. Refers to the upper lobe of the left lung. Topographically projected onto the chest along the anterior surface from the 2nd rib and upward, through the apex to the middle of the scapula.

Segment S3 (anterior) of the left lung. Refers to the upper lobe of the left lung. Topographically, the 2nd to 4th ribs are projected onto the chest in front.

Segment S4 (superior lingular) of the left lung. Refers to the upper lobe of the left lung. Topographically projected onto the chest along the anterior surface of the 4th to 5th ribs.

Segment S5 (lower lingular) of the left lung. Refers to the upper lobe of the left lung. Topographically projected onto the chest along the anterior surface from the 5th rib to the diaphragm.

Segment S6 (superior basal) of the left lung. Refers to the lower lobe of the left lung. Topographically projected onto the chest in the paravertebral region from the middle of the scapula to its lower angle.

Segment S8 (anterior basal) of the left lung. Refers to the lower lobe of the left lung. Topographically delimited anteriorly by the main interlobar groove, inferiorly by the diaphragm, and posteriorly by the posterior axillary line.

Segment S9 (lateral basal) of the left lung. Refers to the lower lobe of the left lung. Topographically projected onto the chest between the scapular and posterior axillary lines from the middle of the scapula to the diaphragm.

Segment S10 (posterior basal) of the left lung. Refers to the lower lobe of the left lung. Topographically projected onto the chest from the lower angle of the scapula to the diaphragm, delimited on the sides by the paravertebral and scapular lines.

An X-ray of the right lung is presented in a lateral projection indicating the topography of the interlobar fissures.

The lungs are located in the chest, occupying most of it, and are separated from each other by the mediastinum. The sizes of the lungs are unequal due to the higher position of the right dome of the diaphragm and the position of the heart, shifted to the left.

Each lung has lobes separated by deep fissures. The right lung consists of three lobes, the left - of two. The right upper lobe accounts for 20% of the lung tissue, the middle lobe - 8%, the lower right lobe - 25%, the upper left lobe - 23%, the lower left lobe - 24%.

The main interlobar fissures are projected on the right and left in the same way - from the level of the spinous process of the 3rd thoracic vertebra they are directed obliquely down and forward and cross the 6th rib at the place where its bony part transitions into the cartilaginous part.

An additional interlobar fissure of the right lung is projected onto the chest along the 4th rib from the midaxillary line to the sternum.

The figure shows: Upper Lobe - upper lobe, Middle Lobe - middle lobe, Lower Lobe - lower lobe

Right lung

Upper lobe:

• apical (S1);
• rear (S2);
• anterior (S3).

Average share:

• lateral (S4);
• medial (S5).

Lower lobe:

• upper (S6);
• mediobasal, or cardiac (S7);
• anterobasal (S8);
• posterobasal (S10).

Left lung

Upper lobe:

• apical-posterior (S1+2);
• anterior (S3);
• upper reed (S4);
• lower reed (S5).

Lower lobe:

• upper (S6);
• anterobasal (S8);
• lateralobasal, or laterobasal (S9);
• posterobasal (S10).

4. Main radiological syndromes of lung diseases:

Radiological symptoms are divided into two large groups. The first group occurs when the air tissue is replaced by a pathological substrate (atelectasis, edema, inflammatory exudate, tuberculoma, tumor). The airless region absorbs X-ray radiation more strongly. An area of ​​darkening is identified on the x-ray. The position, size and shape of the darkening depends on which part of the lung is affected. The second group is caused by a decrease in the volume of soft tissues and an increase in the amount of air (bloating, cavity). In the area of ​​rarefaction or absence of lung tissue, X-ray radiation is delayed less. The radiograph reveals an area of ​​clearing. The accumulation of air or fluid in the pleural cavity produces darkening or clearing. If changes form in the interstitial tissue, these are changes in the pulmonary pattern.

X-ray examination identifies the following syndromes:

• a) extensive darkening of the pulmonary field. With this syndrome, it is important to determine the presence or absence of mediastinal displacement. If the darkening is on the right, then the left contour of the middle shadow is studied, if on the left, then the right contour.

Shift of the mediastinum to the opposite side: effusion pleurisy (uniform shadow), diaphragmatic hernia (inhomogeneous shadow)

No mediastinal displacement: inflammation in the lung tissue (pneumonia, tuberculosis)

Shift to the healthy side: obstructive atelectasis (uniform shadow), lung cirrhosis (heterogeneous shadow), pneumonectomy.

• b) limited dimming. This syndrome can be caused by disease of the pleura, ribs, mediastinal organs, and intrapulmonary lesions. To clarify the topography, it is necessary to perform a lateral photograph. If the shadow is inside the lung and is not adjacent to the chest wall, diaphragm, or mediastinum, then it is of pulmonary origin.

Size corresponds to lobe, segment (infiltration, edema)

Reduction in the size of a lobe or segment (cirrhosis - heterogeneous shadow with clearing, atelectasis - homogeneous)

The dimensions of the compacted area are not reduced, but there are rounded clearings (cavities) in it. If there is a level of fluid in the cavity, then there is an abscess; if the cavity is without fluid, then there is tuberculosis; multiple cavities can be due to staphylococcal pneumonia.

• c) round shadow.

Shadows with a diameter of more than 1 cm, shadows with a diameter of less than 1 cm are called a focus. To decipher this syndrome, I evaluate the following signs: the shape of the shadow, the relationship of the shadow with the surrounding tissues, the contours of the shadow, the structure of the shadow. The shape of the shadow can determine the intrapulmonary or extrapulmonary location of the lesion. An oval or round shadow, most often with an intrapulmonary location, more often it is a cavity filled with fluid (cyst). If the shadow is surrounded on all sides by lung tissue, then it comes from the lung. If the formation is located near the wall, then it comes from the lung, if the largest diameter is in the pulmonary field and vice versa. Fuzzy contours are usually a symptom of an inflammatory process. Clear contours are characteristic of a tumor, fluid-filled cyst, or tuberculoma. The structure of the shadow can be homogeneous or heterogeneous. Heterogeneity may be due to areas of clearing (more dense areas - lime salts, calcification)

• d) ring-shaped shadow

If the ring-shaped shadow in different projections appears within the pulmonary field, this is an absolute criterion for the intrapulmonary cavity. If the shadow has the shape of a semicircle and its wide base is adjacent to the chest, this is an encysted pneumothorax. Wall thickness is important: thin walls (air cyst, tuberculosis cavity, bronchiectasis), uniformly thick walls (tuberculosis cavity, abscess, if there is a fluid level). Multiple ring-shaped shadows can be for various reasons: polycystic pulmonary disease (distributed throughout the lung, diameter more than 2 cm), tuberculosis with several cavities (various in diameter), bronchiectasis (mainly at the bottom, diameter 1-2 cm).

• e) foci and limited disseminations

These are shadows with a diameter of 0.1-1cm. A group of lesions close to each other, spread over two intercostal spaces is limited dissemination, scattered in both lungs is diffuse.

Distribution and location of focal shadows: apexes, subclavian zones - tuberculosis, bronchogenic dissemination occurs with focal pneumonia, tuberculosis.

Contours of the lesions: sharp contours, if localized at the apex, then tuberculosis, if in other parts, then peripheral cancer in the presence of a single focus in another part of the lung.

Shadow structure. Homogeneity indicates focal tuberculosis, heterogeneity indicates tuberculoma.

The intensity is assessed by comparison with the shadow of the blood vessels of the lungs. Low-intensity shadows, in density close to the longitudinal section of the vessels, medium intensity, like the axial section of the vessel, dense focus, more intense than the axial section of the vessels

• f) widespread dissemination of foci. A syndrome in which lesions are scattered over a large portion of one or both lungs. The picture of pulmonary dissemination can be given by many diseases (tuberculosis, pneumonia, nodular silicosis, nodular tumors, metastases, etc.). For diagnosis, the following delineation criteria are used:

Sizes of lesions: miliary (1-2mm), small (3-4mm), medium (5-8mm), large (9-12mm).

Clinical manifestations (cough, shortness of breath, fever, hemoptysis), onset of the disease.

Predominant localization of lesions: unilateral, bilateral, in the upper, middle, lower parts of the pulmonary fields.

Dynamics of lesions: stability, fusion into infiltrates, subsequent disintegration and cavity formation.

• g) pathological changes in the pulmonary pattern. This syndrome includes all deviations from the x-ray picture of the normal pulmonary pattern, which is characterized by a gradual decrease in the size of the shadows from the root to the periphery. Changes in the pulmonary pattern occur with congenital and acquired disorders of blood and lymph circulation in the lungs, diseases of the bronchi, inflammatory and degenerative-dystrophic lesions of the lungs.

Strengthening the pulmonary pattern (increasing the number of pattern elements per unit area of ​​the pulmonary field) occurs with arterial congestion of the lungs (heart defects), compaction of the interlobular and interalveolar septa (pneumosclerosis).

Deformation of the roots of the lungs (in addition to vascular shadows, the images show the lumen of the bronchi, stripes from fibrous cords in the lung tissue). Associated with proliferation and sclerosis of the interstitial tissue of the lung.

Depletion of the pulmonary pattern (reduction in the number of pattern elements per unit area of ​​the pulmonary field)

Bronchopulmonary segments.

Lungs are divided into bronchopulmonary segments, segmenta bronchopulmonalia.

The bronchopulmonary segment is a section of the pulmonary lobe, ventilated by one segmental bronchus and supplied with blood by one artery. The veins that drain blood from the segment pass through the intersegmental septa and are most often common to two adjacent segments. The segments are separated from one another by connective tissue septa and have the shape of irregular cones and pyramids, with the apex facing the hilum and the base facing the surface of the lungs. According to the International Anatomical Nomenclature, both the right and left lungs are divided into 10 segments. The bronchopulmonary segment is not only a morphological, but also a functional unit of the lung, since many pathological processes in the lungs begin within one segment.

IN right lung There are ten bronchopulmonary segments, segmenta bronchopulmonalia.

The upper lobe of the right lung contains three segments, to which segmental bronchi approach, extending from the right upper painful bronchus, bronchus lobaris superior dexter, which is divided into three segmental bronchi:

1) the apical segment (CI), segmentum apicale (SI), occupies the superomedial portion of the lobe, filling the dome of the pleura;

2) the posterior segment (CII), segmentum posterius (SII), occupies the dorsal part of the upper lobe, adjacent to the dorsolateral surface of the chest at the level of the II-IV ribs;

3) the anterior segment (CIII), segmentum anterius (SIII), forms part of the ventral surface of the upper lobe and is adjacent with its base to the anterior wall of the chest (between the cartilages of the 1st and 4th ribs).

The middle lobe of the right lung consists of two segments, to which segmental bronchi approach from the right middle lobar bronchus, bronchus lobaris medius dexter, originating from the anterior surface of the main bronchus; going anteriorly, downward and outward, the bronchus is divided into two segmental bronchi:

1) lateral segment (CIV), segmentum laterale (SIV), with its base facing the anterolateral costal surface (at the level of the IV-VI ribs), and its apex facing upward, posteriorly and medially;

2) the medial segment (CV), segmentum mediale (SV), makes up parts of the costal (at the level of IV-VI ribs), medial and diaphragmatic surfaces of the middle lobe.

The lower lobe of the right lung consists of five segments and is ventilated by the right lower lobar bronchus, bronchus lobaris interior dexter, which gives off one segmental bronchus on its way and, reaching the basal parts of the lower lobe, is divided into four segmental bronchi:

1) the apical (upper) segment (CVI), segmentum apicale (superior) (SVI), occupies the apex of the lower lobe and is adjacent with its base to the posterior chest wall (at the level of the V-VII ribs) and to the spine;

2) the medial (cardiac) basal segment (CVII), segmentum basale mediale (cardiacum) (SVII), occupies the inferomedial part of the lower lobe, extending onto its medial and diaphragmatic surfaces;

3) the anterior basal segment (CVIII), segmentum basale anterius (SVIII), occupies the anterolateral part of the lower lobe, extends onto its costal (at the level of the VI-VIII ribs) and diaphragmatic surface;

4) the lateral basal segment (CIX), segmentum basale laterale (SIX), occupies the mid-lateral part of the base of the lower lobe, partially participating in the formation of the diaphragmatic and costal (at the level of the VII-IX ribs) of its surfaces;

5) the posterior basal segment (CX), segmentum basale posterius (SX), occupies part of the base of the lower lobe, has a costal (at the level of the VIII-X ribs), diaphragmatic and medial surfaces.

IN left lung There are nine bronchopulmonary segments, segmenta bronchopulmonalia.

The upper lobe of the left lung contains four segments, ventilated by segmental bronchi from the left upper lobar bronchus, bronchus lobaris superior sinister, which is divided into two branches - apical and lingular, due to which some authors divide the upper lobe into two parts corresponding to these bronchi:

1) apical-posterior segment (CI+II), segmentum apicoposterius (SI+II), in topography approximately corresponds to the apical and posterior segments of the upper lobe of the right lung;

2) anterior segment (CIII). segment иm anterius (SIII), is the largest segment of the left lung, it occupies the middle part of the upper lobe;

3) the upper lingular segment (CIV), segmentum lingulare superius (SIV), occupies the upper part of the uvula of the lung and the middle parts of the upper lobe;

4) the lower lingular segment (CV), segmentum lingulare inferius (SV), occupies the inferoanterior part of the lower lobe.


The lower lobe of the left lung consists of five segments, which are approached by segmental bronchi from the left lower lobar bronchus, bronchus lobaris inferior sinister, which in its direction is actually a continuation of the left main bronchus.

The segments are separated from each other by connective tissue. In the center of the segment there are a segmental bronchus and an artery, and in the connective tissue septum there is a segmental vein.

According to the International Anatomical Nomenclature, 10 segments are distinguished in the right and left lungs. The names of the segments reflect their topography and correspond to the names of the segmental bronchi.

There are 3 segments in the upper lobe of the right lung:

– apical segment ,segmentum apicale, occupies the superomedial portion of the upper lobe, enters the upper opening of the chest and fills the dome of the pleura;

– posterior segment , segmentum posterius, its base is directed outward and backward, bordering there with the II-IV ribs; its apex faces the upper lobe bronchus;

– anterior segment , segmentum anterius, its base is adjacent to the anterior wall of the chest between the cartilages of the 1st and 4th ribs, as well as to the right atrium and the superior vena cava.

The middle lobe has 2 segments:

– lateral segment , segmentum laterale, its base is directed forward and outward, and its apex is directed upward and medially;

– medial segment, segmentum mediale, comes into contact with the anterior chest wall near the sternum, between the IV-VI ribs; it is adjacent to the heart and diaphragm.

1 – larynx, larynx; 2 – trachea, trachea; 3 – apex of the lung, apex pulmonis; 4 – costal surface, facies costalis; 5 – bifurcation of the trachea, bifurcatio tracheae; 6 – upper lobe of the lung, lobus pulmonis superior; 7 – horizontal fissure of the right lung, fissura horizontalis pulmonis dextri; 8 – oblique fissure, fissura obliqua; 9 – cardiac notch of the left lung, incisura cardiaca pulmonis sinistri; 10 – middle lobe of the lung, lobus medius pulmonis; 11 – lower lobe of the lung, lobus inferior pulmonis; 12 – diaphragmatic surface, facies diaphragmatica; 13 – base of the lung, basis pulmonis.

There are 5 segments in the lower lobe:

– apical segment , segmentumapicale (superius), occupies the wedge-shaped apex of the lower lobe and is located in the paravertebral region;

– medial basal segment , segmentum basale mediale (cardiacum), The base occupies the mediastinal and partly the diaphragmatic surface of the lower lobe. It is adjacent to the right atrium and the inferior vena cava;

– anterior basal segment , segmentum basale anterius, is located on the diaphragmatic surface of the lower lobe, and the large lateral side is adjacent to the chest wall in the axillary region between the VI-VIII ribs;

, segmentum basale laterale, wedged between other segments of the lower lobe so that its base is in contact with the diaphragm, and its side is adjacent to the chest wall in the axillary region, between the VII and IX ribs;

– posterior basal segment , segmentum basale posterius, located paravertebrally; it lies posterior to all other segments of the lower lobe, penetrating deeply into the costophrenic sinus of the pleura. Sometimes it is separated from this segment .

It also distinguishes 10 segments.

The upper lobe of the left lung has 5 segments:

– apical-posterior segment , segmentum apicoposterius, corresponds in shape and position to the apical segment ,segmentum apicale, and posterior segment , segmentum posterius, upper lobe of the right lung. The base of the segment is in contact with the posterior sections of the III-V ribs. Medially, the segment is adjacent to the aortic arch and subclavian artery; may be in the form of two segments;

– anterior segment , segmentum anterius, is the largest. It occupies a significant part of the costal surface of the upper lobe, between the I-IV ribs, as well as part of the mediastinal surface, where it comes into contact with truncus pulmonalis;

– upper lingual segment, segmentumlingulare superius, is a section of the upper lobe between ribs III-V in front and ribs IV-VI in the axillary region;

– lower lingual segment, segmentum lingulare inferius, is located below the upper one, but almost does not come into contact with the diaphragm.

Both lingular segments correspond to the middle lobe of the right lung; they are in contact with the left ventricle of the heart, penetrating between the pericardium and the chest wall into the costomediastinal sinus of the pleura.

In the lower lobe of the left lung there are 5 segments that are symmetrical to the segments of the lower lobe of the right lung:

– apical segment, segmentum apicale (superius), occupies a paravertebral position;

– medial basal segment, segmentum basale mediale, in 83% of cases it has a bronchus that begins with a common trunk with the bronchus of the next segment, segmentum basale anterius. The latter is separated from the lingular segments of the upper lobe, fissura obliqua, and participates in the formation of the costal, diaphragmatic and mediastinal surfaces of the lung;

– lateral basal segment , segmentum basale laterale, occupies the costal surface of the lower lobe in the axillary region at the level of the XII-X ribs;

– posterior basal segment, segmentum basale posterius, is a large area of ​​the lower lobe of the left lung located posterior to other segments; it comes into contact with the VII-X ribs, the diaphragm, the descending aorta and the esophagus;

– segmentum subapicale (subsuperius) this one is not always available.

The lung segments consist of from secondary pulmonary lobules, lobuli pulmones secundarii, each of which includes a lobular bronchus (4-6 orders). This is a pyramidal-shaped area of ​​pulmonary parenchyma up to 1.0-1.5 cm in diameter. Secondary lobules are located on the periphery of the segment in a layer up to 4 cm thick and are separated from each other by connective tissue septa, which contain veins and lymphocapillaries. Dust (coal) is deposited in these partitions, making them clearly visible. In both lungs there are up to 1 thousand secondary lobes.

5) Histological structure. alveolar tree, arbor alveolaris.

The pulmonary parenchyma, according to its functional and structural features, is divided into two sections: conductive - this is the intrapulmonary part of the bronchial tree (mentioned above) and respiratory, which carries out gas exchange between the venous blood flowing to the lungs through the pulmonary circulation and the air in the alveoli.

The respiratory section of the lung consists of acini, acinus, – structural and functional units of the lung, each of which is a derivative of one terminal bronchiole. The terminal bronchiole divides into two respiratory bronchioles, bronchioli respiratorii, on the walls of which alveoli appear, alveoli pulmones,-cup-shaped structures lined from the inside with flat cells, alveolocytes. Elastic fibers are present in the walls of the alveoli. At the beginning, along the respiratory bronchiole, there are only a few alveoli, but then their number increases. Epithelial cells are located between the alveoli. In total, there are 3-4 generations of dichotomous division of respiratory bronchioles. Respiratory bronchioles, expanding, give rise to the alveolar ducts, ductuli alveolares(from 3 to 17), each of which ends in blind alveolar sacs, sacculi alveolares.The walls of the alveolar ducts and sacs consist only of alveoli, intertwined with a dense network of blood capillaries. The inner surface of the alveoli, facing the alveolar air, is covered with a film of surfactant - surfactant, which equalizes surface tension in the alveoli and prevents their walls from gluing - atelectasis. In the lungs of an adult there are about 300 million alveoli, through the walls of which gases diffuse.

Thus, respiratory bronchioles of several orders of branching, extending from one terminal bronchiole, alveolar ducts, alveolar sacs and alveoli form the pulmonary acinus, acinus pulmonis. The respiratory parenchyma of the lungs has several hundred thousand acini and is called the alveolar tree.

The terminal respiratory bronchiole and the alveolar ducts and sacs extending from it form the primary lobule, lobulus pulmonis primarius. There are about 16 of them in each acini.

6) Age-related features. The lungs of a newborn have an irregular cone shape; the upper lobes are relatively small in size; The middle lobe of the right lung is equal in size to the upper lobe, and the lower lobe is relatively large. In the 2nd year of a child’s life, the size of the lobes of the lung relative to each other becomes the same as in an adult. The weight of the newborn’s lungs is 57 g (from 39 to 70 g), volume 67 cm³. Age-related involution begins after 50 years. The boundaries of the lungs also change with age.

7) Developmental anomalies. Pulmonary agenesis – absence of one or both lungs. If both lungs are missing, the fetus is not viable. Lung hypogenesis – underdevelopment of the lungs, often accompanied by respiratory failure. Anomalies of the terminal parts of the bronchial tree – bronchiectasis – irregular saccular dilatations of terminal bronchioles. Reverse position of the thoracic cavity organs, while the right lung contains only two lobes, and the left lung consists of three lobes. The reverse position can be only thoracic, only abdominal and total.

8) Diagnostics. During an X-ray examination of the chest, two light “lung fields” are clearly visible, by which the lungs are judged, since due to the presence of air in them, they easily transmit X-rays. Both pulmonary fields are separated from each other by an intense central shadow formed by the sternum, spinal column, heart and large vessels. This shadow constitutes the medial border of the lung fields; the upper and lateral borders are formed by ribs. Below is the diaphragm. The upper part of the pulmonary field is crossed by the clavicle, which separates the supraclavicular region from the subclavian region. Below the clavicle, the anterior and posterior parts of the ribs intersecting each other are layered onto the pulmonary field.

The X-ray method of research allows you to see changes in the relationships of the chest organs that occur during breathing. When you inhale, the diaphragm lowers, its domes flatten, the center moves slightly downwards - the ribs rise, the intercostal spaces become wider. The pulmonary fields become lighter, the pulmonary pattern becomes clearer. The pleural sinuses “clear up” and become noticeable. The position of the heart approaches vertical, and it takes on a shape close to triangular. When you exhale, the opposite relationship occurs. Using X-ray kymography, you can also study the work of the diaphragm during breathing, singing, speech, etc.

With layer-by-layer radiography (tomography), the structure of the lung is revealed better than with ordinary radiography or fluoroscopy. However, even on tomograms it is not possible to differentiate individual structural formations of the lung. This becomes possible thanks to a special method of x-ray examination (electroradiography). The radiographs obtained using the latter show not only the tubular systems of the lung (bronchi and blood vessels), but also the connective tissue frame of the lung. As a result, it is possible to study the structure of the parenchyma of the entire lung in a living person.

In the chest cavity there are three completely separate serous sacs - one for each lung and one, middle, for the heart.

The serous membrane of the lung is called the pleura, p1eura. It consists of two sheets:

visceral pleura pleura visceralis;

pleura parietal, parietal pleura parietalis.

how many lobes are in the left lung

how many lobes are in the right lung

In the Other section, to the question Why the number of lobes in the right and left lung of a person is not the same, asked by the author Oksana, the best answer is: Each lung is divided into lobes by means of grooves. One groove, oblique, on both lungs, begins relatively high (6-7 cm below the apex) and then descends obliquely down to the diaphragmatic surface, going deep into the substance of the lung. It separates the upper lobe from the lower lobe of each lung. In addition to this groove, the right lung also has a second, horizontal groove, passing at the level of the IV rib. It demarcates from the upper lobe of the right lung a wedge-shaped area that makes up the middle lobe. Thus, the right lung has three lobes.

In the left lung, only two lobes are distinguished: the upper, to which the apex of the lung extends, and the lower, more voluminous than the upper. It includes almost the entire diaphragmatic surface and most of the posterior obtuse edge of the lung. On the anterior edge of the left lung, in its lower part, there is a cardiac notch, where the lung, as if pushed aside by the heart, leaves a significant part of the pericardium uncovered. From below, this notch is limited by a protrusion of the anterior edge, called the tongue. The uvula and the adjacent part of the lung correspond to the middle lobe of the right lung.

Original source Because there is a heart that occupies a certain place.