Topographic anatomy of the lungs. Topography of the pleura and lungs. Segmental structure of the lungs. Operative approaches to the organs of the thoracic cavity. Evolution of the respiratory system


Skeletotopia. The projection of the lungs onto the ribs constitutes their boundaries, which are determined by tapping (percussion) or x-ray. The apices of the lungs are 3-4 cm above the collarbone, and at the back they reach the level of the spinous process of the VII cervical vertebra.
The anterior border of the right lung runs from the apex to the II rib along the linea parasternalis and further along the same line to the VI rib, where it passes into the lower border. The anterior border of the left lung in the 3rd rib runs the same way as the anterior border of the right, and in the 4th intercostal space it deviates to the linea medioclaricularis, from where it descends to the 6th rib and also passes into the lower border.

The lower border of the right lung crosses the 6th rib linea parasternalis 7 linea medioclavicularis 8 - linea axillaris media 9 linea axillaris posterior, 10 - along the line a scapularis, XI - along the linea paravertebral. The lower border of the left lung is located 1-1.5 cm below the right.
The posterior border of the right and left lungs runs from the apex to the 11th rib along the linea paravertebrals.

Syntopy. The subclavian artery is adjacent to the apex of the lung on the medial side. The costal surface, being covered with the parietal pleura, is separated behind the intrathoracic fascia from the intercostal vessels and nerves. The basis of the lungs lies on the diaphragm. In this case, the diaphragm separates the right lung from the liver, and the left lung from the spleen, left kidney and adrenal glands, stomach, transverse colon and liver.

The medial surface of the right lung in front of the hilum is adjacent to the right atrium; above - to the right brachiocephalic and superior vena cava; behind the gate - to the esophagus. The medial surface of the left lung in front of the hilum is adjacent to the left ventricle; above - to the aortic arch and the left brachiocephalic vein; behind the gate - to the thoracic aorta.
The topography of the root elements of the right and left lungs is not exactly the same. On the right, the main bronchus is located superiorly; below is the pulmonary artery; in front and below of which are the pulmonary veins. At the root of the left lung, the pulmonary artery lies above, below and behind it is the main bronchus, in front and below it are the pulmonary veins.

Anterior to the root of the right lung are the ascending aorta, the superior vena cava, pericardium and part of the right atrium, above and behind - the azygos vein. The aortic arch is adjacent to the root of the left lung in front, and the esophagus is behind. The phrenic nerves run along both roots in front and the vagus nerves in the back.

In newborns, the lungs expand with the first breath. At the end of the 1st year of life, their volume increases 4 times; at the end of the 8th year - 8 times; at 12 years old - 10 times. The apex of the lungs in newborns reaches only the first rib, and the lower border is higher than in adults.
Blood supply lungs has its own characteristics. Arterial blood enters the lungs through the bronchial arteries, and venous blood flows out through the veins of the same name. In addition, venous blood enters the lungs through the pulmonary arteries. The pulmonary arteries are divided into lobar and segmental, which further branch according to the structure of the bronchial tree. Capillaries, having formed, entwine the alveoli. This ensures gas exchange between the air in the alveoli and the blood. Capillaries form venous vessels that carry arterial blood into the pulmonary veins. The systems of pulmonary and bronchial vessels are not completely isolated - there are anastomoses between their terminal branches.
Lymphatic vessels and nodes of the lungs. In the lungs there are superficial and deep lymphatic vessels. Superficial ones are formed from pleural lymphatic capillaries. Deep ones are formed from capillary networks around the terminal bronchioles, interacynary and interlobular spaces. The drainage lymphatic vessels pass through the regional lymph nodes, which are divided into:
1) pulmonary, nodi lymphoidei pulmonales, located in the parenchyma of the lungs, mainly at the sites of division of the bronchi;
2) bronchopulmonary, nodi lymphoidei bronchopulmonales, located in the area of ​​the hilum of the lungs;
3) upper tracheobronchial, nodi lymphoidei tracheohronchiales sup., lying along the trachea and the upper surface of the main bronchi;
4) lower tracheobronchial or bifurcation, nodi lymphoidei tracheobronchiales inf., located on bottom surface bifurcation of the trachea and main bronchi;
5) paratracheal, nodi lymphoidei paratracheales, located along the trachea.
Innervation The lungs are provided by branches of the vagus nerve, branches of the nodes of the sympathetic trunk, as well as branches of the phrenic nerve, which form the pulmonary plexus at the gates of the lungs, pl. pulmonalis. The pulmonary plexus is divided into anterior and posterior, its branches form the peribronchial and perivascular plexuses. Sensitive innervation of the lungs is carried out by cells of the lower node of the vagus nerve and cells of the lower cervical and upper thoracic spinal nodes. Nerve impulses from the bronchi are carried out mainly along the ferent fibers of the vagus nerves, and from the visceral pleura - along the ferent spinal fibers.
Sympathetic innervation of the lungs is carried out from the cells of the lateral horns along the Th II-V segments of the spinal cord. Parasympathetic innervation - from the cells of the posterior nucleus of the vagus nerve. The axons of these cells reach the lungs as part of the branches of the vagus nerve.

Pleura, pleura, is the serous membrane of the lungs, which consists of a connective tissue base covered with mesothelium. There are two layers in the pleura: visceral (pulmonary) and parietal pleura, pleura visceralis (pulmonalis) et parietalis. The latter is divided into the mediastinal part, pars mediastinalis, which limits the mediastinum on the sides; costal, pars costalis, covering the inside chest wall, and diaphragmatic, pars diaphragmatica. At the lower edge of the lung root, the visceral pleura transforms into the parietal pleura and forms a fold - the pulmonary ligament, ligamentum pulmonale.
The slit-like space between the parietal and visceral pleura is called the pleural cavity, cavitas pleuralis. U healthy person this cavity is filled with 1-2 ml of serous fluid. At pathological conditions(pleurisy) the amount of fluid increases significantly. The latter is secreted by the free surface of mesothelial cells (mesothelial cells). Under normal conditions, mesotheliocytes also provide absorption of this fluid. In pathological conditions (pleurisy), the amount of fluid increases significantly, since the processes of excretion prevail over the processes of absorption. Between various parts In the parietal pleura, three slit-like spaces are formed - pleural sinuses, recessus pleurales. The largest of them passes between the costal and diaphragmatic pleura - the costophrenic sinus, recessus costodiaphragmaticus. The second lies sagittally between the diaphragmatic and mediastinal pleura - the diaphragmatic-mediastinal sinus, recessus phrenicomediastinalis. The third is located vertically between the costal and mediastinal pleura - the costomedial sinus, recessus costo-mediastinalis. The pleural sinuses constitute the reserve spaces into which the lungs enter during maximum inspiration. With pleurisy, fluid accumulates primarily in the pleural sinuses, and later in the pleural cavity.
The level of the apexes of the pleural sacs (the dome of the pleura, cupula pleurae) coincides with the level of the apexes of the lungs.
The anterior border of the pleural sacs runs from the apex to the sternoclavicular joint. Further on the right it passes to the midline at the level of the angle of the sternum, from where it descends to the level of the VI-VII rib and passes into the lower border. On the left, at the level of the VI rib, the anterior border deviates laterally, then descends to the VI rib, where it becomes the lower border.
The lower border on the right along the linea medioclavicularis intersects the VII rib, along the linea axillaris media - IX, along the linea scapularis - XI, no linea paravertebral - XII. On the left, the lower border runs slightly lower.
The posterior border of the pleural sacs runs from the dome to the 12th rib along the linea paravertebral.

Mediastinum, mediastinum, is a complex of organs located between the mediastinal pleura. In front it is limited by the anterior chest wall; behind - the spine, necks of the ribs and prevertebral fascia; below - the diaphragm. The mediastinum is divided into: upper, mediastinum superius, and lower, mediastinum imferius, which in turn includes the anterior mediastinum, mediastinum anterius; middle, mediastinum medium, and back, mediastinum posterius. The border between the upper and lower passes along a conventional horizontal plane, which is drawn through the upper edge of the roots of the lungs. In the upper mediastinum lies the thymus or its remnants, the ascending aorta and the aortic arch with its branches, the superior vena cava with its tributaries, the trachea, the esophagus, the thoracic duct, the sympathetic trunks, the vagus nerves, the trachea, the phrenic nerves, The lymph nodes.

Anterior mediastinum located between the body of the sternum and the pericardium. It includes fiber and processes of the intrathoracic fascia, in the leaves of which the internal thoracic arteries and veins, retrosternal and anterior mediastinal lymph nodes are located. The middle mediastinum contains the pericardium with the heart, the bifurcation of the trachea and the main bronchi, the pulmonary trunk, pulmonary arteries and veins, the phrenic nerves with the accompanying phrenic-pericardial vessels, and lymph nodes. The posterior mediastinum is located between the pericardium and the bifurcation of the trachea anteriorly and the spine posteriorly. It includes the descending aorta, vagus nerves, sympathetic trunks, esophagus, thoracic duct, lymph nodes and more.

1. The muscle that is on one side the thoraco-abdominal barrier, and on the other side the respiratory muscle:

A) diaphragm;

B) rectus abdominis muscle;

C) external oblique muscle;

D) transverse abdominal muscle;

E) serratus muscle.

2. Openings leading from the nasal cavity to the pharynx:

B) pharyngeal;

D) superior nasal passage;

E) sinus of the sphenoid bone.

3. The smallest branches of the bronchial “tree”:

A) lobar bronchi;

B) lobular bronchi;

C) terminal bronchioles;

D) segmental bronchi;

E) respiratory (respiratory) bronchioles.

4. Organ for coarse and fine air purification:

A) nasopharynx;

B) trachea;

C) bronchi;

D) nasal cavity;

E) larynx;

5. Hole from oral cavity down the throat:

IN) Eustachian tube;

WITH) maxillary sinus;

D) jugular;

6. Part of the nasal cavity, which is called the olfactory cavity:

A) middle nasal meatus;

B) top;

C) lower;

E) external nose.

7. Main organs respiratory system:

A) bronchi;

B) pulmonary artery;

C) acicuses;

D) lungs;

E) alveoli.

8. Pressure in the pleural fissure:

A) 760 mmHg;

B) – 9 mmHg;

C) 510 mmHg;

D) above atmospheric;

E) – 19 mm Hg. Art.

9. Organ where the respiratory and digestive tracts intersect:

A) larynx;

B) pharynx;

C) esophagus;

10. The main respiratory muscles of a woman:

A) abdominal muscles;

B) diaphragm;

C) intercostal;

D) staircases;

E) serrated.

11. A distinctive feature of the human external nose in comparison with other vertebrates:

A) flattened;

B) protruding on the face;

C) depressed;

D) forked;

E) having two halves.

12. Average tracheal length:

A) 25 – 30 cm;

B) 40 – 41 cm;

C) 6 – 8 cm;

D) 5 – 10 cm;

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LECTURE 13. TOPOGRAPHIC ANATOMY OF THE CHEST WALL

1. Boundaries. Upper– along the jugular notch, along the upper edge of the clavicles, clavicular-acromial joints and along conditional lines drawn from this joint to the spinous process of the VII cervical vertebra . Lower– from the base of the xiphoid process, along the edge of the costal arch to the X rib, from where along conventional lines through the free ends of the XI-XII ribs it goes to the spinous process of the XII thoracic vertebra. Borders chest do not comply with boundaries chest cavity, because the dome of the diaphragm protrudes into the chest cavity. The anterior surface of the chest is unevenly convex due to the pectoralis major muscles (mammary glands). Below the collarbone, in the outer third, are the subclavian fossae. Projection jugular sternal notch – lower edge of the second thoracic vertebra, angle of the sternum – level intervertebral disc IV–V thoracic vertebrae. The lower edge of the body of the sternum is the X thoracic vertebra. The lower angle of the scapula is the upper edge of the VIII rib. Conditional vertical lines:

Anterior midline - from the jugular notch to the middle of the sternum

Sternal lines - along the edges of the sternum

Midclavicular lines - through the middle of the clavicles

Parasternal lines - in the middle of the distance between the sternal and midclavicular lines

Anterior axillary lines - from the anterior edge of the axillary fossae

Posterior axillary lines - from the posterior edge of the axillary fossae

Mid-axillary lines - in the middle of the distance between the anterior and posterior axillary lines

Scapular lines - through the lower angles of the shoulder blades

Paravertebral lines - at the level of the ends of the transverse processes

Posterior midline - through the spinous processes of the thoracic vertebrae.

2. The structure of the chest wall.

The skin contains sebaceous and sweat glands, numerous in the area of ​​the sternum, shoulder blades and lateral surface, where retention cysts. The superficial fascia on the anterior side forms the capsule of the mammary gland. Bundles of fascia running from the upper edge of the capsule to the clavicle - suspensory ligament mammary gland. The mammary gland consists of 15–20 lobules with excretory milk ducts. They converge radially at the nipple, where they form milky sinuses. The proper fascia of the chest consists of two layers - superficial and deep, forming fascial sheaths for the pectoralis major and minor muscles, and on the posterior wall - for the lower part of the trapezius muscle and the latissimus dorsi muscle. A deep leaf borders the osteo-fibrous bed of the scapula, with located muscles, vessels and nerves. Deep layer adjacent to the extensor muscle of the back - thoracolumbar fascia. The anterior surface is formed by the sternum, costal cartilages, ribs and intercostal spaces filled with internal and external intercostal muscles. On the lower edges of the ribs there are grooves where the musculoskeletal intercostal space is formed. fascial-cellular the space in which the vein is located, below it - the artery and nerve. Anterior to the midaxillary line, the vessels and nerves are not covered by the ribs. The posterior surface of the chest is formed by the ribs and intercostal spaces, and near the spine - intertransverse at intervals. The upper opening of the chest is formed by the upper edge of the jugular notch, the first ribs, and the body of the 1st thoracic vertebra. Through it, the domes of the right and left pleura and the apex of the lungs protrude into the supraclavicular region, the trachea, esophagus, vessels and nerves pass through. The lower opening is closed by the diaphragm and separates the chest and abdominal cavities. The projection of the diaphragm attachment goes along the lower edge of the xiphoid process, above and parallel to the lower edge of the costal arch, along the XII rib and the bodies of the III–IV lumbar vertebrae. The left dome is in front at the level of the upper edge of the 5th rib, and behind the 9th intercostal space, the right dome is higher.

6. Puncture pleural cavity. This is a puncture of the chest wall and parietal pleura for the purpose of diagnosis or treatment. Indications – exudative pleurisy, pleural empyema, hydrothorax, pneumothorax, hemothorax, chylothorax, pneumothorax, pleural tumors. The place for puncture is the VII or VIII intercostal space between the middle axillary and scapular lines, perpendicular to the skin.

The puncture site is determined using percussion, auscultation and fluoroscopy. To suction air, a puncture is made in the 2nd or 3rd intercostal space along the midclavicular line. The puncture point should correspond to the upper edge of the rib to avoid damage to the intercostal vessels and nerves. Evacuation of exudate is carried out slowly so as not to cause rapid displacement of the mediastinum.

LECTURE 14. SURGERY ON THE CHEST WALL

1. Mastitis– inflammation of the parenchyma and interstitium of the mammary gland. Surgery is performed when pus accumulates in the mammary gland. The opening is carried out with linear incisions directed radially to the isola. Intramammary abscesses are opened with radial incisions. For deep abscesses and phlegmons, an arcuate incision is made along the skin fold under the mammary gland. The gland is pulled up and its posterior surface is exposed. The purulent cavity is opened with a radial incision, and bridges and pockets are eliminated. The cavity is drained with tubular drainages. They also open retromammary phlegmons and abscesses located between the mammary gland and the pectoral fascia. This method avoids intersection of the intralobular milk ducts, ensures good drainage and a cosmetic effect.

4. Radical mastectomy – removal of the mammary gland en bloc along with subcutaneous tissue, pectoralis major and minor muscles, adjacent fascia and lymph nodes. Is the leading method surgical treatment breast cancer.

Skin incisions:

medial– from the outer third of the clavicle to the middle of the sternum, down the parasternal line and ends at the costal arch

lateral– along the outer edge of the gland along the anterior border of the axillary fossa, connecting the ends of the previous incision.

Skin flap separation goes up - to the collarbone, medially - to the middle of the sternum, laterally - to the anterior edge of the latissimus dorsi muscle, down - to the costal arch. Dissect subcutaneous tissue and fascia, the tendon part of the pectoralis major muscle is isolated and crossed. It is separated from the clavicle and sternum, preserving the clavicular portion. The pectoralis minor muscle is cut off from the coracoid process of the scapula, pulled down, exposing the subclavian tissue, which is removed along with the lymph nodes.

5. Sectoral resection. The operation is performed when benign tumors, fibrocystic mastopathy, cysts, suspected malignant tumor. The incision is radial, from the edge of the isola above the formation. The edges of the skin are separated to the sides and the corresponding lobules of the gland are excised. When the process is localized near the areola, the incision is made along its edge (pigmentation border). Excision of a section of the gland from the lower quadrants - arcuate along the course skin fold under the gland.

LECTURE 15. TOPOGRAPHIC ANATOMY OF THE THORACIC CAVITY

In the chest cavity there are:

Lateral spaces with lungs located in them

Mediastinum - pericardium, heart, thymus, esophagus, trachea and main bronchi, thoracic lymphatic duct, lymph nodes, fascial-cellular formations.

1. Mediastinum limited anteriorly by the sternum and retrosternal fascia, posteriorly by the thoracic spine, necks of the ribs and prevertebral fascia. Lateral borders– mediastinal pleura with leaves of the intrathoracic fascia. Lower– diaphragm and phrenic fascia . Up separated from the fascial-cellular spaces of the neck by fascial cords and plates (level of the superior foramen). Conditional division by 4 departments– top, front, middle and back. Upper– thymus gland, brachiocephalic veins, upper part of the superior vena cava, aortic arch, trachea, esophagus, thoracic lymphatic duct, sympathetic trunks, vagus and phrenic nerves, fascia and cellular spaces. Front– between the body of the sternum and the anterior wall of the pericardium, contains spurs of the intrathoracic fascia (thoracic vessels, parasternal, prepericardial, anterior mediastinal lymph nodes). Average– heart, tracheal bifurcation, main bronchi, pulmonary arteries and veins, phrenic nerves, lymph nodes. Rear– limited by the bifurcation of the trachea, the posterior wall of the pericardium, the bodies of the IV–XII thoracic vertebrae and contains the descending aorta, azygos and semi-gypsy veins, sympathetic trunks, intravenous and vagus nerves, esophagus, thoracic duct, lymph nodes.

2. Pericardium – a closed sac surrounding the heart, the ascending aorta before it passes into the arch, the pulmonary trunk to the place of its division, the mouth of the vena cava and pulmonary veins. It consists of an outer fibrous and serous pericardium, represented by the parietal and visceral plates. Between the plates there is a serous pericardial cavity. In the pericardium there are 4 departments:

Front – sternocostal(from the transitional fold on the ascending aorta and the pulmonary trunk of the diaphragm) is adjacent to the chest wall, where it is fixed by the sternopericardial ligaments. The part adjacent to the V–VII left costal cartilages is not covered by the pleura; the pericardium is opened here without damaging the pleura

Lower – diaphragmatic department - fused with the tendon center of the diaphragm, where the phrenic-pericardial ligaments pass

Lateral – pleural– adjacent to the mediastinal pleura

Rear – mediastinal- a triangular plate located between the vessels of the heart root.

Between the pericardium and the wall of the heart there are sinus cavities. Anteroinferior sinus– the angle between the sternum and the diaphragm, the pericardium is punctured here. In the area of ​​the posterior wall there are two isolated sinuses. Transverse– limited to the posterior surface of the ascending aorta and pulmonary trunk, the posterior wall of the pericardium and the right pulmonary artery. In the heart there is a base directed upward and somewhat posteriorly; the apex facing anteriorly, downward and to the left. Surfaces of the heart - anterior ( sternocostal), lower (diaphragmatic), side ( pulmonary). In the heart they distinguish two edges– left (rounded), right (sharper).

Skeletotopy of the heart. The right border of the heart runs from the upper edge of the cartilage of the 2nd rib, at the place of attachment on the right to the sternum, to the upper edge of the cartilage of the 3rd rib, 1–1.5 cm outward from the right edge of the sternum. Next - from the III to V ribs in the form of an arc, spaced 1-2 cm from the right edge of the sternum. At the level of the V ribs it passes into the lower one, which runs along an oblique line down and to the left, crossing the sternum above the base of the xiphoid process, then to the 6th intercostal space on the left and through the cartilage of the 6th rib into the 5th intercostal space. The left border of the heart is from the 1st rib at the point of attachment to the sternum on the left to the 2nd rib 2 cm to the left of the left sternal line (projection of the aortic arch). At the level of the 2nd intercostal space - 2–2.5 cm outward from the left edge of the sternum (projection of the pulmonary trunk). The continuation of the line at the level of the third rib corresponds to the left cardiac auricle. From the lower edge of the third rib, 2–2.5 cm to the left of the left sternal line - in the form of an arc, corresponding to the left edge of the left ventricle, to the 5th intercostal space 1.5–2 cm inward from the midclavicular line, where the apex is projected hearts. Projection right atrioventricular holes and tricuspid valve - along the line connecting the sternal end of the 5th rib with the outer end of the cartilage of the 1st left rib; left atrioventricular holes and double-leaf valve – left edge of the sternum at the level of the 3rd intercostal space; arterial the hole with the semilunar valves of the pulmonary trunk is at the left edge of the sternum at the level of the cartilage of the third rib.

4. Thymus gland,thymus, located in the upper interpleural space and adjacent to the retrosternal fascia. Behind the gland are the brachiocephalic veins and the aortic arch, below and behind the pericardium. It is surrounded by a thin fascial sheath, from which fascial spurs extend. The gland sheath is connected with the fascial sheath of the brachiocephalic veins, aortic arch, pericardium, costomedial folds of the pleura and the retrosternal fascia.

5. Thoracic esophagus in the upper and posterior mediastinum it is adjacent at level from II to XI

thoracic vertebrae, separated by prevertebral fascia and tissue. Curves of the esophagus:

To the level of the IV thoracic vertebra - to the left

At the level of the IV–V thoracic vertebrae – anterior to the spine

At the level of the IV thoracic vertebra - to the right of the midline

At the level of the VIII–IX thoracic vertebrae - anterior to the spine, in front of the thoracic aorta.

In the upper mediastinum - located behind the trachea. At the level of the tracheal bifurcation, it is adjacent to the postero-right surface of the aortic arch and borders the carotid and left subclavian arteries. Below the aortic arch is fixed esophageal-tracheal ligaments to the left main bronchus and tracheal bifurcation. In the posterior mediastinum, it is adjacent to the descending aorta and at the level of the IV–VII thoracic vertebrae passes to its anterior surface. Level XI of the thoracic vertebra – hiatus diaphragm.

LECTURE 16. TOPOGRAPHIC ANATOMY OF TRACHEA, BRONCHI, PLEURA

1. Thoracic trachea located in the upper mediastinum and projected onto the sternum to the right of the midline of the body. The bifurcation of the trachea and the main bronchi are located in the middle mediastinum. Projection the upper border of the trachea is the notch of the sternum in front and the II thoracic vertebra behind, the lower border is the angle of the sternum in the front, the intervertebral cartilage of the IV–V thoracic vertebrae is behind. Here the trachea divides into the right and left main bronchi ( bifurcation), which is projected onto the V–VII thoracic vertebrae. Anterior to the bifurcation is the right pulmonary artery. Below is the pericardium and the adjacent right atrium. Along the posterior and superior wall of the right main bronchus there is azygos vein. Posteriorly and to the left of the trachea is the esophagus, along the right surface is the right nervus vagus. Recurrent laryngeal nerve lies in the esophageal-tracheal groove. Below to the left lateral surface of the trachea is adjacent aortic arch, passing over the left bronchus. The trachea, tracheal bifurcation, main bronchi, esophagus and surrounding tissue have a common esophageal-tracheal fascial membrane. With the help of cords and plates, it is connected to the surrounding formations by the fascial beds of the thymus gland, the aortic arch and its branches, pulmonary vessels, intrathoracic fascia, etc., limiting the pretracheal, interbronchial and paraesophageal spaces.

2. Thoracic duct is formed in the retroperitoneal space as a result of the fusion of the right and left lumbar trunks at the level of the II lumbar vertebra. IN posterior mediastinum it enters through the aortic opening of the diaphragm, to the right and behind the aorta. The duct passes in a vertical direction to the right of the midline in the prevertebral tissue between the layers of the prevertebral fascia, passing between the thoracic aorta and the azygos vein. It is located in an oblique direction from the aortic arch and esophagus, then along the left mediastinal pleura towards the upper opening of the chest, where it passes to the dome of the pleura, bending around it, from back to front, into the left venous angle. Posterior to the aortic arch is adjacent to the esophagus and can be damaged during esophageal surgery.

3. Topography of the pleura.Pleura- a thin serous membrane covering the lung (visceral pleura) and delimiting the mediastinum from the formations (parietal pleura). Between the leaves a slit-like space is formed - the pleural cavity containing serous fluid. Depending on the parts of the thoracic cavity, there are costal, diaphragmatic, mediastinal pleura. The anterior borders of the pleura (the line of transition of the costal to the mediastinal), on the right - crosses the sternoclavicular joint, goes down and inward along the manubrium of the sternum, passes obliquely from right to left, crossing the midline at the level of the cartilage of the 2nd rib, then goes vertically down to the level of the cartilage of the 6th rib (transition to the lower limit); on the left - it also begins, goes along the left edge of the sternum to the attachment of the 4th rib, then goes outward, crossing the 4th intercostal space, the rib cartilage, the 5th intercostal space and at the level of the cartilage of the 6th rib it passes into the lower border. The lower borders pass along the midclavicular line along the VII rib, along the midaxillary line - along the X rib, along the scapular line - along the XI rib, along the paravertebral line - along the XII rib. The posterior boundaries correspond to the costovertebral joints. The dome of the pleura protrudes above the collarbone and corresponds posteriorly to the level of the spinous process of the VII cervical vertebra, and in front is projected 2–3 cm above the collarbone. Pleural sinus - the place of transition of one part of the parietal pleura to another. Costophrenic The sinus is located at the level of attachment of the diaphragm in the form of a semicircle from the cartilage of the sixth rib to the spine. On the back right it reaches the azygos vein, on the left it reaches the aorta. When you inhale, it does not fill with the lungs. The mediastinal-diaphragmatic, anterior and posterior costal-mediastinal ones are smaller and, when inhaling, are filled with the lungs entirely. Pulmonary ligament- a fold of the mediastinal pleura that forms below the hilum of the lungs and connects the parietal and visceral pleura. When mobilizing the lower lobe of the lung, it is usually divided.

LECTURE 17. TOPOGRAPHIC ANATOMY OF THE LUNG

1. Topography of the lungs. Lungs- paired organs occupying most of the thoracic cavity. They are separated from each other by the mediastinum. There is a top and three surfaces:

External ( costal), adjacent to the ribs and intercostal spaces

Lower ( diaphragmatic), adjacent to the diaphragm;

Internal ( mediastinal), adjacent to the mediastinal organs.

The left lung has two beats(top and bottom), and on the right - three beats(top, middle and bottom). The oblique fissure in the left lung separates the upper lobe, and in the right, the upper and middle lobes from the lower. An additional horizontal fissure in the right lung separates the middle lobe from the upper lobe. Skeletotopy of the lungs. The anterior and posterior boundaries of the lungs almost coincide with the boundaries of the pleura. Anterior border of the left lung, due to the cardiac notch, starting from the cartilage of the IV rib, it deviates towards the left midclavicular line. Lower limits lungs correspond on the right along the sternal line, on the left along the parasternal line to the cartilage of the VI rib, along the midclavicular line to the upper edge of the VII rib, along the anterior axillary line to the lower edge of the VII rib, along the middle axillary line to the VIII rib, along the scapular line to the X rib, along the paravertebral lines – XI rib. When inhaling, the border of the lung descends.

2. Segments- areas of lung tissue ventilated by the segmental bronchus and separated from adjacent segments by connective tissue. Each lung consists of 10 segments.

Right lung:

upper lobe – apical, posterior, anterior segments

middle lobe – lateral, medial segments

lower lobe – apical, medial basal, anterior basal,

lateral basal, posterior basal segments.

Left lung:

Upper lobe – two apical-posterior, anterior, upper lingular, lower lingular

Lower lobe - apical, medial-basal, anterior basal, lateral basal, posterior basal segments... On inner surface the lung has a gate. Root right lung:

Above is the main bronchus,

Below and anteriorly is the pulmonary artery,

Even lower is the pulmonary vein.

Root left lung:

Above is the pulmonary artery,

Below and posteriorly is the main bronchus.

The pulmonary veins are adjacent to the anterior and inferior surfaces of the main bronchus and artery.

The projection of the hilum onto the anterior chest wall corresponds to the V–VIII thoracic vertebrae in the back and the II–IV ribs in the front.

LECTURE 18. OPERATIVE SURGERY OF THE LUNG AND PLEURA

1. Lung resection– removal of part of the lung. The stages of the operation are separation of the lung from adhesions, treatment of blood vessels and bronchi, drainage of the pleural cavity. In cases of adhesions between the parietal and visceral pleura, the isolation of the lung should be complete, which makes it possible to clarify the volume and nature of the lesion and straighten the remaining parts of the lung after lobectomy or segmentectomy. The adhesions are cut with an electric knife, a thermal cautery, or sutured and bandaged. When removing a lung that is firmly fused with the parietal pleura over its entire surface, it is isolated together with the pleura - extrapleurally. This will reduce blood loss, prevent the opening of superficially located abscesses and cavities, and in the presence of pleural empyema, it will allow the lung to be removed along with the purulent sac without opening it. At extrapleural After isolating the lung, the dense parietal pleura is separated from all walls of the chest cavity. Near the anterior and posterior edges of the lung, the parietal pleura is dissected and root of the lung fit intrapleurally. Intersection of blood vessels and bronchi carried out after their separate processing. First - the pulmonary arteries, so that after ligation of the veins it can be removed part of the lung did not overflow with blood. In patients with lung cancer, the pulmonary veins are first ligated, which prevents cancer cells from being released into the bloodstream. The vessels are exposed after dissection of the visceral pleural layer and separation of the fiber. The adventitia is dissected and pulled apart. The vessel is dissected between piercing ligatures. The bronchus is transected so that the length of its remaining stump does not exceed 5–7 mm. The stump is sutured through all layers. Sutures are placed so that the membranous part of the bronchus is pulled towards the cartilaginous part. First, the central suture is applied, and 2-3 more sutures are placed on the sides. After tying all the threads, the stump takes on a crescent shape. The bronchial stump is additionally covered with pleura - pleurisy. To cover the stump of a lobar or segmental bronchus, adjacent lung tissue is used. Isolated removal of one or more segments of the lung is carried out after intersection of the segmental artery and bronchus. Suturing the lung reduces its volume and impairs ventilation. Atypical resections are carried out by applying one or two UO devices to the lung, with the help of which the lung tissue is sutured with tantalum staples. If necessary, additional interrupted or U-shaped sutures are applied.

Drainage of the pleural cavity performed during all lung operations before suturing the chest wall. After pneumonectomy, a valve drain is placed through the 8th intercostal space along the posterior axillary line; after partial removal of the lung, two drains with multiple lateral holes are inserted into the pleural cavity. One of them is placed along the back wall, the other along the front wall of the chest cavity, connecting them to the system for constant suction.

2. Pneumonectomy– removal of the entire lung. Thoracotomy performed by lateral access along the fifth intercostal space, posterior access along the sixth, or anterior access along the fourth or fifth intercostal space. The lung is completely isolated, the pulmonary ligament is ligated and dissected. Dorsal to the phrenic nerve and parallel to it, the mediastinal pleura is dissected above the root of the lung.

At right pneumonectomy after dissection of the mediastinal pleura, the anterior trunk of the right pulmonary artery is discovered in the upper part of the lung root. In the mediastinal tissue, the right pulmonary artery is found and isolated, processed, ligated with suturing, and transected. The superior and inferior pulmonary veins are also treated and divided. The right main bronchus is isolated to the trachea, sutured with a UO apparatus and transected. The suture line is pleurized with a mediastinal pleura flap.

At left pneumonectomy After dissection of the mediastinal pleura, the left pulmonary artery and then the superior pulmonary vein are immediately isolated, processed and transected. Pulling the lower lobe laterally, the inferior pulmonary vein is isolated, treated and transected. The bronchus is pulled out from the mediastinum and isolated to the tracheobronchial angle, processed and transected. There is no need to pleurize the stump of the left main bronchus, since it goes into the mediastinum under the aortic arch.

3. Pneumotomy– opening of the lung cavities, performed for fibrous-cavernous tuberculosis ( cavernotomy) and very rarely in acute lung abscess. For cavities in the upper lobes of the lung, pneumotomy is performed from the side of the axillary fossa (vertical incision), and for cavities in the lower lobes - slightly below the angle of the scapula (incision along the ribs). 2-3 ribs are exposed and subperiosteally resected over a distance of 10–12 cm, corresponding to the projection of the cavity in the lung. The posterior layer of the periosteum, intrathoracic fascia and parietal pleura are dissected. If the pleural cavity is closed, a test puncture of the lung is performed with a thick needle connected to a syringe. To avoid air embolism the syringe should be partially filled with saline solution. When pus is obtained, the cavity in the lung is opened with an electric knife, necrotic and purulent masses are removed. The outer wall of the cavity is excised as widely as possible. The cavity is packed. The edges of the skin are rolled into the wound and sutured to the edges of the periosteum and thickened parietal pleura.

5. Pleurectomy– radical removal of the pleura in chronic empyema with decortication of the lung. Resection of the 5th or 6th rib is performed from the lateral approach. The pleural sac is bluntly peeled off from the dome to the diaphragm. Dorsally, the bag is peeled off to the spine, ventrally - to the root of the lung. Next, the transition points between the parietal wall of the sac and the visceral wall are dissected and the lung is exposed. The next stage is the separation of the empyema sac from the lung. Dense adhesions are cut with scissors. The entire bag with purulent contents is removed. The lung is inflated and for better expansion decortication– removal of fibrous deposits. Two drains with multiple holes are inserted into the chest cavity from the dome to the diaphragm.

Thanks to the development and improvement of modern equipment, widely used for various types of diagnostics, it is possible to successfully examine the condition of the internal organs of the human body. With the help of quite popular computed tomography, whose work is based on the body through x-rays, without much effort, the condition of the body’s lungs is studied. How does this happen?

To perform a computed tomography scan of the lungs, a specially trained technologist is invited who can work on a special scanner that displays the resulting image on a computer monitor.

Thanks to computed tomography of the lungs, it is possible to detect various oncological changes in their structure in the early stages of their occurrence.

Before the topographic examination, the patient is asked to undress and remove all possible jewelry. This also applies to earrings and piercings. If a person ignores this rule, then during examination the equipment will definitely react to metal, which can cause unforeseen situations. The patient is then asked to lie down on a special table and not move for a certain period of time. The technologist leaves the room where the patient and topographic equipment are located and observes what is happening through a special window. The patient and the technologist communicate this or that information to each other through the use of a special selector.

The image obtained as a result of a topographic scan of the lungs is carefully studied by a team of doctors, which includes: a pulmonologist, a surgeon, a radiologist and a family doctor.

Topography of the lungs in children

To determine the child’s health, they often resort to the method of topographic examination of the lungs. Thanks to this method, it is possible to identify different respiratory systems on early stages their development.

In childhood, abdominal breathing predominates. Therefore, the topography of the lungs is very necessary. With the development of various types of diseases in the body, the lungs begin to change the boundaries of their location due to changes in their structure. Typically, the lower boundaries with this arrangement begin to fall somewhat due to an increase in the volume fraction of the lungs. This is observed when these organs are affected by emphysema or are acutely swollen. The reason for this may be a low position of the diaphragm or its paralysis.

Thanks to a topographic examination of the child’s lungs, it is possible to find their lower border of the lungs by feeling the mid-axillary or posterior axillary line.

In this case, the child must take a deep breath and hold his breath for a while. This position is used to determine the location of the lower lung boundaries. The doctor relies on data obtained from the sound and sensation of his fingers.


Mature people also need topographical lungs. Such a study is also very important for confirming the diagnosis of a particular disease. This type of study is called topographic percussion.

Using this method you can determine:

  • Location of the inferior borders of each lung
  • Location upper limits lungs
  • The degree of mobility of their lower

Due to the development of various diseases in the lung cavity, the volume of each of them can change significantly. At the same time, it only increases, but also decreases. Such changes can be detected due to the changes that occur in the positions of the pulmonary edges. The doctor compares the changes obtained with normal ones and draws appropriate conclusions.

To determine the position of the edges of the lungs, normal human breathing is sufficient.

Some fluctuation is allowed in the position of the lower edge of one of the lungs. The reason for this is the height of the diaphragmatic dome, which depends on the gender of the person, his physique and age limits. For men, this parameter is slightly higher than for women.

A video from which you can learn the anatomical structure of the lungs in the human body.

Lungs(pulmones) - a paired organ located in the chest cavity that carries out gas exchange between inhaled air and blood.

The lungs are shaped like halves of a vertically dissected cone; they are covered with a serous membrane - the pleura. With a long and narrow chest, the lungs are elongated and narrow; with a wide chest, they are shorter and wider. The right L. is shorter and wider than the left and larger in volume. Each L. has an apex, a base, three surfaces (costal, medial, diaphragmatic) and two edges (anterior and inferior). On the costal surface of the apex of the lung there is a groove corresponding subclavian artery, and in front of it is the groove of the brachiocephalic vein. On the costal surface there is also a variable imprint of the first rib - the subapical groove. The costal and diaphragmatic surfaces of the flap are separated by a pointed lower edge. When inhaling and exhaling, the lower edge of the lung moves in the vertical direction by an average of 7-8 cm. The medial surface of the L. is separated from the costal surface in front by a pointed anterior edge, and from below from the diaphragmatic surface by the lower edge. On the anterior edge of the left lung there is a cardiac notch that passes down into the uvula of the lung. On the medial surface of both lungs, a distinction is made between the vertebral and mediastinal parts and the cardiac depression. In addition, on the medial surface of the right L., in front of its gate, there is an impression from the junction of the superior vena cava, and behind the gate there are shallow grooves from the junction of the azygos vein and the esophagus. Approximately in the center of the medial surface of both L. there is a funnel-shaped depression - the gate of the L. Skeletotopically, the gate of the L. corresponds to the level of the V-VII thoracic vertebrae in the back and the II-V ribs in the front. The main bronchus, pulmonary and bronchial arteries and veins, nerve plexuses, and lymphatic vessels pass through the portal of the lungs; Lymph nodes are located in the hilum area and along the main bronchi. The listed anatomical formations together make up the root of L. Upper part The portal of the lungs is occupied by the main bronchus, the pulmonary artery and lymph nodes, bronchial vessels and the pulmonary nerve plexus. The lower part of the portal is occupied by the pulmonary veins. The root of L. is covered with pleura. Below the root of the lung, a triangular pulmonary ligament is formed by the duplication of the pleura.

The lungs consist of lobes separated from each other by interlobar fissures, which are 1-2 cm do not reach the root of the lung. In the right L. there are three lobes: upper, middle and lower. The upper lobe is separated from the middle lobe by a horizontal fissure, the middle lobe from the lower lobe by an oblique fissure. In the left L. there are two lobes - upper and lower, separated by an oblique fissure. L.'s lobes are divided into bronchopulmonary segments - sections of the lung, more or less isolated from the same neighboring sections by connective tissue layers, in each of which a segmental bronchus and the corresponding branch of the pulmonary artery branch; the veins draining the segment drain blood into the veins located in the intersegmental septa. In accordance with the International Nomenclature (London, 1949), 10 bronchopulmonary segments are distinguished in each lung. In the International Anatomical Nomenclature (PNA), the apical segment of the left L. is combined with the posterior one (apical-posterior segment). The medial (cardiac) basal segment of the left L. is sometimes absent.



In each segment, several pulmonary lobes are distinguished - sections of the lung, within which the branching of the lobular bronchus (small bronchus with a diameter of about 1 mm) up to the terminal bronchiole; the lobules are separated from each other and from the visceral pleura by interlobular septa made of loose fibrous and connective tissue. There are about 800 lobules in each lung. Ramifications bronchi (including terminal bronchioles) form the bronchial tree, or airways of the lungs.

The terminal bronchioles are dichotomously divided into respiratory (respiratory) bronchioles of the 1st-4th order, which, in turn, are divided into alveolar ducts (passages), branching from one to four times, and ending in alveolar sacs. On the walls of the alveolar ducts, alveolar sacs and respiratory bronchioles, the alveoli of the lungs open into their lumen. The alveoli, together with the respiratory bronchioles, alveolar ducts and sacs, make up the alveolar tree, or the respiratory parenchyma of the lung; its morphofunctional unit is the acinus, which includes one respiratory bronchiole and associated alveolar ducts, sacs and alveoli.



The bronchioles are lined with single-layer cuboidal ciliated epithelium; they also contain secretory and brush cells. The wall of the terminal bronchioles lacks glands and cartilaginous plates. The connective tissue surrounding the bronchioles passes into the connective tissue basis of the respiratory parenchyma of the lung. In the respiratory bronchioles, cuboidal epithelial cells lose cilia; upon transition into the alveolar ducts, the cuboidal epithelium is replaced by single-layer squamous alveolar epithelium. The alveolar wall, lined with single-layer squamous alveolar epithelium, contains three types of cells: respiratory (scaly) cells, or type 1 alveolocytes, large (granular) cells, or type 2 alveolocytes, and alveolar phagocytes (macrophages). On the air space side, the epithelium is covered with a thin non-cellular layer of surfactant - a substance consisting of phospholipids and proteins produced by type 2 alveolocytes. Surfactant has pronounced surface-active properties, prevents the collapse of the alveoli during exhalation, the penetration of microorganisms from the inhaled air through their walls, and prevents the transudation of liquid from the capillaries. The alveolar epithelium is located on the basement membrane with a thickness of 0.05-0.1 µm. Outside the basement membrane there are blood capillaries running along the interalveolar septa, as well as a network of elastic fibers entwining the alveoli.

The apex of the lung in an adult corresponds to the dome of the pleura and protrudes through the upper aperture of the chest into the neck to the level of the apex of the spinous process of the VII cervical vertebra behind and 2-3 cm above the collarbone in front. The position of the borders of the l. and parietal pleura is similar. The anterior edge of the right L. is projected onto the anterior chest wall along a line drawn from the apex of the L. to the medial end of the clavicle, continuing to the middle of the manubrium of the sternum and further down to the left of the sternum line until the attachment of the VI costal cartilage to the sternum, where the lower border of the L. begins. The anterior edge of the left L. at the level of the connection of the IV rib with the sternum deviates in an arcuate manner to the left and down to the intersection of the VI rib with the parasternal line. The lower border of the right L. corresponds on the sternum line to the cartilage of the 5th rib, along the midclavicular line to the 6th rib, along the anterior axillary line to the 7th rib, along the scapular line to the 10th rib, and along the paravertebral line to the spinous process of the 11th thoracic vertebra. The lower border of the left L. differs from the same border of the right L. in that it begins on the cartilage of the VI rib along the parasternal line. In newborns, the apexes of the lungs are at the level of the first ribs; by the age of 20-25 they reach a level normal for an adult. The lower border of the lungs of newborns is one rib higher than that of adults; in subsequent years it falls. In people over 60 years of age, the lower limit of L. is 1-2 cm lower than that of 30-40 year olds.

The costal surface of the L. is in contact with the parietal pleura. At the same time, intercostal vessels and nerves are adjacent to the L., separated from them by the pleura and intrathoracic fascia. The base of the lens lies on the corresponding dome of the diaphragm. The right L. is separated by the diaphragm from the liver, the left - from the spleen, left kidney with adrenal gland, stomach, transverse colon and liver. The medial surface of the right L. in front of its gate is adjacent to the right atrium, and above - to the right brachiocephalic and superior vena cava, behind the gate - to the esophagus. The medial surface of the left L. is adjacent in front of the gate to the left ventricle of the heart, and above - with the aortic arch and the left brachiocephalic vein, behind the gate - with the thoracic part of the aorta. The syntopy of the roots of L. is different on the right and left. Anterior to the root of the right lung are the ascending aorta, the superior vena cava, the pericardium, and partly the right atrium; above and behind - azygos vein. The aortic arch is adjacent to the root of the left lung from above, and the esophagus is located behind it. Both roots are crossed in front by the phrenic nerves, and in the back by the vagus nerves.

Blood supply carried out by pulmonary and bronchial vessels. The pulmonary vessels included in the pulmonary circulation primarily perform the function of gas exchange. Bronchial vessels provide nutrition to the lungs and belong to the systemic circulation. There are quite pronounced anastomoses between these two systems. Outflow venous blood occurs through intralobular veins flowing into the veins of the interlobular septa. The veins of the subpleural connective tissue also drain here. From the interlobular veins, intersegmental veins, veins of segments and lobes are formed, which at the hilum of the lungs merge into the upper and lower pulmonary veins.

The beginning lymphatic ducts L. are superficial and deep networks of lymphatic capillaries. The superficial network is located in the visceral pleura. From it the lymph passes into the plexus of lymphatic vessels of the 1st, 2nd and 3rd orders. Deep capillary network located in the connective tissue inside the pulmonary lobules, in the interlobular septa, in the submucosa of the bronchial wall, around the intrapulmonary blood vessels and bronchi. Regional lymph nodes of L. are combined into the following groups: pulmonary, located in the parenchyma of the lungs, mainly at the sites of division of the bronchi; bronchopulmonary, located in the area of ​​​​branching of the main and lobar bronchi; upper tracheobronchial, located on the lower part of the lateral surface of the trachea and in the tracheobronchial angles; lower tracheobronchial, or bifurcation, located on the lower surface of the tracheal bifurcation and on the main bronchi; peritracheal, located along the trachea.

Innervation carried out by the pulmonary nerve plexus, which is formed by the vagus nerve, nodes of the sympathetic trunk and the phrenic nerve. At the gate of L. it is divided into anterior and posterior plexuses. Their branches form peribronchial and perivasal plexuses in L., accompanying the branches of the bronchi and blood vessels.

Topography of the mediastinum.

Mediastinum(mediastinum) - part of the thoracic cavity, bounded in front by the sternum and behind by the spine. Covered with intrathoracic fascia, on the sides - with mediastinal pleura. From above, the border of S. is the upper aperture of the chest, from below - the diaphragm. The mediastinum contains the heart and pericardium, large vessels and nerves, trachea and main bronchi, esophagus, thoracic duct.

The mediastinum is conventionally divided (along the plane passing through the trachea and main bronchi) into anterior and posterior. In the front are thymus , right and left brachiocephalic and superior vena cava, ascending part and arch aorta , its branches, heart And pericardium , in the posterior - the thoracic part of the aorta, the esophagus, the vagus nerves and sympathetic trunks, their branches, the azygos and semi-gypsy veins, thoracic duct . In the anterior S. there are upper and lower sections (the lower one contains the heart). Loose connective tissue surrounding organs, communicates at the top through the anterior S. with the previsceral cellular space of the neck, through the back - with the retrovisceral cellular space of the neck, at the bottom through the holes in the diaphragm (along the para-aortic and peri-esophageal cellular tissue) - with the retroperitoneal cellular tissue. Between the fascial sheaths of organs and vessels of the S., interfascial gaps and spaces are formed, filled with fiber, forming fiber spaces: pretracheal - between the trachea and the aortic arch, in which the posterior part of the thoracic aortic plexus is located; retrotracheal - between the trachea and the esophagus, where the paraesophageal nerve plexus and posterior mediastinal lymph nodes lie; left tracheobronchial, where the aortic arch, left vagus nerve and left upper tracheobronchial lymph nodes are located; right tracheobronchial, which contains the azygos vein, right vagus nerve, right upper tracheobronchial lymph nodes. Between the right and left main bronchi there is an interbronchial, or bifurcation, space with the lower tracheobronchial lymph nodes located in it.

Blood supply is provided by the branches of the aorta (mediastinal, bronchial, esophageal, pericardial); The outflow of blood occurs into the azygos and semi-amygos veins. Lymphatic vessels conduct lymph to the tracheobronchial (upper and lower), peritracheal, posterior and anterior mediastinal, prepericardial, lateral pericardial, prevertebral, intercostal, perithoracic lymph nodes. S.'s innervation is carried out by the thoracic aortic nerve plexus.

"Krasnoyarsk State Medical University named after. Professor Voino-Yasenetsky

Ministry of Health and Social Development of the Russian Federation"

Department of Anatomy

Test on anatomy

Topic: “Lungs, their structure, topography and functions. Lobes of the lung. Bronchopulmonary segment. Light excursion"

Krasnoyarsk 2009


PLAN

Introduction

1. Structure of the lungs

2. Macro-microscopic structure of the lungs

3. Lung boundaries

4. Lung functions

5. Ventilation

6. Embryonic development of the lungs

7. Lungs of a living person (X-ray examination of the lungs)

8. Evolution of the respiratory system

9. Age-related characteristics of the lungs

10. Congenital lung malformations

Bibliography


Introduction

The human respiratory system is a set of organs that ensure external respiration in the body, or the exchange of gases between the blood and the external environment and a number of other functions.

Gas exchange is carried out by the lungs and is normally aimed at absorbing oxygen from the inhaled air and releasing carbon dioxide formed in the body into the external environment. In addition, the respiratory system is involved in such important functions as thermoregulation, voice production, smell, and humidification of inhaled air. Lung tissue also plays an important role in processes such as the synthesis of hormones, water-salt and lipid metabolism. In a richly developed vascular system blood is deposited in the lungs. The respiratory system also provides mechanical and immune protection against environmental factors.

The main organs of the respiratory system are the lungs.


1. Structure of the lungs

Lungs (pulmones) are paired parenchymal organs that occupy 4/5 of the chest cavity and constantly change shape and size depending on the phase of breathing. Located in the pleural sacs, separated from each other by the mediastinum, which includes the heart, large vessels (aorta, superior vena cava), esophagus and other organs.

The right lung is more voluminous than the left (by approximately 10%), at the same time it is somewhat shorter and wider, firstly, due to the fact that the right dome of the diaphragm is higher than the left (due to the voluminous right lobe liver) and, secondly, the heart is located more to the left, thereby reducing the width of the left lung.

Lung shape. Surfaces. The edges

The lung has the shape of an irregular cone with a base directed downward and a rounded apex, which stands 3–4 cm above the first rib or 2 cm above the collarbone in front, and in the back it reaches the level of the VII cervical vertebra. At the apex of the lungs a small groove is noticeable from the pressure of the subclavian artery passing here

There are three surfaces in the lung. The lower (diaphragmatic) is concave according to the convexity of the upper surface of the diaphragm to which it is adjacent. The extensive costal surface is convex according to the concavity of the ribs, which, together with the intercostal muscles lying between them, form part of the wall of the thoracic cavity. The mediastinal surface is concave, adapting for the most part to the contours of the pericardial sac, and is divided into an anterior part adjacent to the mediastinum and a posterior part adjacent to the spine.

The surfaces of the lung are separated by edges. The anterior edge separates the costal surface from the medial one. There is a cardiac notch on the anterior edge of the left lung. This notch is limited below by the uvula of the left lung. The costal surface behind gradually passes into the vertebral part of the medial surface, forming a blunt posterior edge. The lower edge separates the costal and medial surfaces from the diaphragmatic surface.

On the medial surface, above and posterior to the depression made by the pericardial sac, there are the gates of the lung, through which the bronchi, pulmonary artery, and nerves enter the lung, and two pulmonary veins and lymphatic vessels exit, all together forming the root of the lung. At the root of the lung, the bronchus is located dorsally, but the position of the pulmonary artery is different on the right and left sides. At the root of the right lung pulmonary the artery is located below the bronchus, on the left side it crosses the bronchus and lies above it. The pulmonary veins on both sides are located in the root of the lung below the pulmonary artery and bronchus. At the back, at the junction of the costal and medial surfaces of the lung, no sharp edge is formed; the rounded part of each lung is placed here in the recess of the chest cavity on the sides of the spine.

Lung lobes

Each lung is divided into lobes by means of grooves deeply protruding into it, of which the left lung has two, and the right lung has three. One groove, oblique, present on both lungs, begins relatively high (6 - 7 cm below the apex) and then obliquely descends down to the diaphragmatic surface, going deep into the substance of the lung. She separates on every upper lung share of the bottom. 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: upper, middle and lower. 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.

Branching of the bronchi. Bronchopulmonary segments

According to the division of the lungs into lobes, each of the two main bronchi, approaching the gates of the lung, begins to divide into lobar bronchi, of which there are three in the right lung and two in the left. The right upper lobar bronchus, heading towards the center of the upper lobe, passes over the pulmonary artery and is called supradarterial; the remaining lobar bronchi of the right lung and all the lobar bronchi of the left pass under the artery and are called subarterial. Lobar bronchi, entering the substance of the lung, they are divided into a number of smaller, tertiary bronchi, called segmental. They ventilate lung segments. The segmental bronchi, in turn, are divided dichotomously into smaller bronchi of the 4th and subsequent orders up to the terminal and respiratory bronchioles. Each segmental bronchus of the lung corresponds to the bronchopulmonary neurovascular complex.

A segment is a section of lung tissue that has its own vessels and nerve fibers. Each segment resembles a truncated cone in shape, the apex of which is directed towards the root of the lung, and the wide base is covered with visceral pleura. In the center of the segment there is a segmental bronchus and a segmental artery, and on the border with the adjacent segment there is a segmental vein. The pulmonary segments are separated from each other by intersegmental septa, consisting of loose connective tissue, in which intersegmental veins pass (pavovascular zone). Normally, the segments do not have clearly defined visible boundaries; sometimes they are noticeable due to differences in pigmentation. Bronchopulmonary segments are functional and morphological units of the lung, within which some pathological processes are initially localized and the removal of which can be limited to some sparing operations instead of resections of an entire lobe or the entire lung. There are many classifications of segments.

Representatives of different specialties (surgeons, radiologists, anatomists) highlight different number segments (from 4 to 12). Thus, for the purposes of X-ray diagnostics, D. G. Rokhlin drew up a diagram of the segmental structure, according to which there are 12 segments in the right lung (three in the upper lobe, two in the middle and seven in the lower) and 11 in the left lung (four in the upper lobe and seven - at the bottom). According to the International (Paris) Anatomical Nomenclature, 11 bronchopulmonary segments are distinguished in the right lung, and 10 in the left (Fig. 2).

2. Macro-microscopic structure of the lung

The segments are formed by pulmonary lobules separated by interlobular connective tissue septa. Interlobular connective tissue contains veins and networks of lymphatic capillaries and contributes to the mobility of the lobules during respiratory movements of the lung. With age, inhaled coal dust is deposited in it, as a result of which the boundaries of the lobules become clearly visible. The number of lobules in one segment is about 80. The shape of the lobule resembles an irregular pyramid with a base diameter of 1.5–2 cm. The apex of the lobule includes one small (1 mm in diameter) lobular bronchus, which branches into 3–7 terminal bronchioles with a diameter of 0.5 mm. They no longer contain cartilage and glands. Their mucous membrane is lined with single-layer ciliated epithelium. The lamina propria of the mucous membrane is rich in elastic fibers, which pass into the elastic fibers of the respiratory department, due to which the bronchioles do not collapse.

Acinus

The structural and functional unit of the lung is the acinus (Fig. 4). It is a system of alveoli that carry out gas exchange between blood and air. The acinus begins with a respiratory bronchiole, which is dichotomously divided 3 times; third-order respiratory bronchioles are dichotomously divided into alveolar ducts, which are also three orders. Each third-order alveolar duct ends in two alveolar sacs. The walls of the alveolar ducts and sacs are formed by several dozen alveoli, in which the epithelium becomes single-layer squamous (respiratory epithelium). The wall of each alveoli is surrounded by a dense network of blood capillaries.

Respiratory bronchioles, alveolar ducts and alveolar sacs with alveoli form a single alveolar tree, or respiratory parenchyma of the lung. They form its functional-anatomical unit, called the acinus, acinus (bunch).

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