Anatomy of the lungs

Anatomy of the lungsAnatomical features of the lungs. Functions of the lungs. Blood supply and innervation of the lungs
~ 3 min

Lungs (pulmones)

Lungs (pulmones)
Lungs (pulmones)

Lungs are paired respiratory organs located in the thoracic cavity, on the left and right sides, separated by the central mediastinum (mediastinum)

Mediastinum (mediastinum)
Mediastinum (mediastinum)

Holotopy

They are projected onto the anterior thoracic wall in the sternal, nipple, and subcostal regions; onto the posterior thoracic wall in the scapular and infrascapular regions.

Skeletotopy

The apices of the lungs are located 3-4 cm above the clavicle, the apex of the right lung is slightly higher than the apex of the left one. Posteriorly, they are projected onto the 7th cervical vertebra.

The anterior border of the right lung is directed downward from the apex and is projected at the middle of the symphysis of the manubrium of the sternum. Then it goes behind the body of the sternum slightly to the left of the median line, and at the 6th rib, it passes into the inferior border. It departs from the sternum at the height of the 6th rib and descends steeply downwards

Anatomical lineRightLeft
Anterior median lineNear the edge of the VI rib , it passes into the lower borderRounding the heart, from the level of cartilage of the VI rib, deviates to the left to the parasternal line. At the cartilage of the VI rib, the anterior border of the left lung passes into the inferior one
Midclavicular lineRib VIForms the сardiac notch
Anterior axillary lineRib VIIRib VII
Midaxillary lineRib VIIIRib VIII
Posterior axillary lineRib IXRib IX
Scapular lineRib XRib X
Paravertebral line (paraspinal line)At the level of the spinous process of the XI vertebraAt the level of the spinous process of the XI vertebra

Syntopy

The internal surface of the thoracic cavity is attached to the costal surface, and the diaphragm is located below. The subclavian artery lies in front of the apices, the esophagus adheres to the mediastinal surface of the right lung behind the root, and the superior vena cava and azygos vein lie below. The aorta (the arch and the descending part) adheres to the left lung behind its root, the brachiocephalic veins are at the top, and the heart adheres to the anterior part.

Each lung is covered with the pleura, which consists of two sheaths, namely the visceral pleura (pleura visceralis), which adheres tightly to the lung,

Visceral pleura (pleura visceralis)
Visceral pleura (pleura visceralis)

And the parietal pleura (pleura parietalis), which lines the thoracic cavity from the inside.

Parietal pleura (pleura parietalis)
Parietal pleura (pleura parietalis)

Between the sheaths, there is the pleural cavity (cavitas pleuralis), which is filled with a small amount of pleural fluid.

Pleural cavity (cavitas pleuralis)
Pleural cavity (cavitas pleuralis)

In the lung, the following parts are distinguished:

The base of the lung (basis pulmonis)

Base of the lung (basis pulmonis)
Base of the lung (basis pulmonis)

The apex of the lung (apex pulmonis)

Apex of the lung (apex pulmonis)
Apex of the lung (apex pulmonis)
Apex of the lung (apex pulmonis)
Apex of the lung (apex pulmonis)

The apices are located about 2-4 cm above the 1st rib and the clavicle. Subclavian arteries adhere to the apices.

There are also three surfaces in the lung:

The diaphragmatic surface (facies diaphragmatica)

Diaphragmatic surface (facies diaphragmatica)
Diaphragmatic surface (facies diaphragmatica)
Diaphragmatic surface (facies diaphragmatica)
Diaphragmatic surface (facies diaphragmatica)

The costal surface (facies costalis)

Costal surface (facies costalis)
Costal surface (facies costalis)
Costal surface (facies costalis)
Costal surface (facies costalis)

The medial surface (facies medialis), which adheres to the mediastinum.

Medial surface (facies medialis)
Medial surface (facies medialis)

On the medial surface of the organ, there is the hilum of the lung (hilum pulmonis) through which the root of the lung (radix pulmonis) passes

Hilum of the lung (hilum pulmonis)
Hilum of the lung (hilum pulmonis)

It includes the main bronchus, artery, and veins.

In the right lung, going from top to bottom, lie the right main bronchus, right pulmonary artery, and pulmonary veins (BAV).

Right main bronchus
Right main bronchus
Right pulmonary artery
Right pulmonary artery
Right pulmonary veins
Right pulmonary veins

In the left lung, the left pulmonary artery is located above all, the left bronchus is lower, and the pulmonary veins are even lower (ABV).

Left pulmonary artery
Left pulmonary artery
Left main bronchus
Left main bronchus
Left pulmonary veins
Left pulmonary veins

The surfaces of the lung have their proper borders:

The inferior border (margo inferior)

Inferior border (margo inferior)
Inferior border (margo inferior)
Inferior border (margo inferior)
Inferior border (margo inferior)

The anterior border (margo anterior)

Anterior border (margo anterior)
Anterior border (margo anterior)

The pulmonary groove (sulcus pulmonalis)

The right lung is 10% larger than the left one. It is somewhat wider and shorter since the diaphragm adheres to it from below. The liver, in turn, presses on the diaphragm. The main bronchi also differ from each other. The right bronchus is slightly wider and shorter than the left one.

The main bronchi of the lungs form the right and left halves of the bronchial tree. It is discussed in greater detail in a separate video.

Each lung is divided into lobes consisting of segments.

The right lung (pulmo dexter) has three lobes:

1. The superior lobe (lobus superior)

Superior lobe (lobus superior)
Superior lobe (lobus superior)

2. The middle lobe (lobus medius)

Middle lobe (lobus medius)
Middle lobe (lobus medius)

3. The inferior lobe (lobus inferior)

Inferior lobe (lobus inferior)
Inferior lobe (lobus inferior)

These lobes, in turn, are separated by two fissures. These are the oblique fissure (fissura obliqua)

Oblique fissure (fissura obliqua)
Oblique fissure (fissura obliqua)
Oblique fissure (fissura obliqua)
Oblique fissure (fissura obliqua)

and the horizontal fissure (fissura horisontalis)

Horizontal fissure (fissura horisontalis)
Horizontal fissure (fissura horisontalis)
Horizontal fissure (fissura horisontalis)
Horizontal fissure (fissura horisontalis)

The left lung (pulmo sinister) has two lobes:

1. The superior lobe (lobus superior)

Superior lobe (lobus superior)
Superior lobe (lobus superior)

2. The inferior lobe (lobus inferior)

Inferior lobe (lobus inferior)
Inferior lobe (lobus inferior)

They are separated by the oblique fissure (fissura obliqua)

Oblique fissure (fissura obliqua)
Oblique fissure (fissura obliqua)
Oblique fissure (fissura obliqua)
Oblique fissure (fissura obliqua)

There is the cardiac notch (incisura cardiaca) on the medial surface of the left lung, to which the heart adheres.

Cardiac notch (incisura cardiaca)
Cardiac notch (incisura cardiaca)
Cardiac notch (incisura cardiaca)
Cardiac notch (incisura cardiaca)
Cardiac notch (incisura cardiaca)
Cardiac notch (incisura cardiaca)

From below, the notch passes into the lingula (lingula pulmonis sinistri), which somewhat mimics the middle lobe of the lung

Lingula (lingula pulmonis sinistri)
Lingula (lingula pulmonis sinistri)
Lingula (lingula pulmonis sinistri)
Lingula (lingula pulmonis sinistri)
Lingula (lingula pulmonis sinistri)
Lingula (lingula pulmonis sinistri)

A segment is a structural element of the lung, which includes a part of the pulmonary parenchyma, a segmental bronchus, and an artery.

The segment consists of lobules, which are formed by pulmonary acini.

Pulmonary acinus
Pulmonary acinus

The acini consist of alveolar ducts (ductuli alveolares) and alveolar sacs (sacculi alveolares).

Alveolar ducts (ductuli alveolares)
Alveolar ducts (ductuli alveolares)
Alveolar sacs (sacculi alveolares)
Alveolar sacs (sacculi alveolares)

The ducts and sacs have protrusions in their walls called alveoli.

Alveoli
Alveoli

The alveoli are the terminal part of the respiratory system, where gas exchange takes place. From the inside, they are covered with a special substance called surfactant, which prevents them from collapsing and sticking together, maintaining their surface tension.

Between the alveoli and the bloodstream, there is the blood-air barrier, which regulates the gas exchange from the alveoli to the blood and vice versa.

It consists of the surfactant, type 1 pneumocytes, basal membrane, and endothelium.

Blood supply

The lungs are supplied with arterial blood by the bronchial branches of the thoracic aorta.

Venous drainage

Venous drainage is carried out by the bronchial veins into the tributaries of the pulmonary veins, as well as into the azygos and hemi-azygos veins.

Innervation

Innervation of the lungs is carried out by the vagus nerve, as well as by the sympathetic trunk, the branches of which form the pulmonary plexus (plexus pulmonalis) in the area of the root of the lung.

Dictionary

Anatomy of the lunges

Lungs
pulmones
Mediastinum
mediastinum
Visceral pleura
pleura visceralis
Parietal pleura
pleura parietalis
Pleural cavity
cavitas pleuralis
Base of the lung
basis pulmonis
Apex of the lung
apex pulmonis
Diaphragmatic surface
facies diaphragmatica
Costal surface
facies costalis
Medial surface
facies medialis
Hilum of the lung
hilum pulmonis
Root of the lung
radix pulmonis
Inferior border
margo inferior
Anterior border
margo anterior
Pulmonary groove
sulcus pulmonalis
Right lung
pulmo dexter
Superior lobe
lobus superior
Middle lobe
lobus medius
Inferior lobe
lobus inferior
Oblique fissure
fissura obliqua
Cardiac notch
incisura cardiaca
Lingula
lingula pulmonis sinistri
Pulmonary plexus
plexus pulmonalis
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