Anatomy of the bronchial tree

Anatomy of the bronchial treeAnatomical features of the bronchial tree. Functions of the bronchial tree. Blood supply and innervation of bronchial tree
~ 5 min

The bronchial tree is a part of the lower respiratory tract that begins at the level of tracheal bifurcation and ends with small bronchioles that pass into the alveolar sacs.

Holotopy

They are projected onto the sternal and nipple areas of the anterior thoracic wall.

Skeletotopy

They are located at the level of the thoracic 5th and 6th vertebrae.

Syntopy

The azygos vein (v. azygos) passes through the right main bronchus in the form of an arch from behind to the front, and the aortic arch lies above the left main bronchus. In the hilum of the lungs behind the right bronchus lies the pulmonary artery and pulmonary veins, the right vagus nerve; anteriorly and superiorly, there is the azygos vein; inferiorly, there are the lymphatic nodes of the bifurcation; the pulmonary artery is located anteriorly to the left bronchus, pulmonary veins are located posteriorly, the aortic arch is located superiorly, the descending aorta, the left vagus nerve, and esophagus are located posteriorly, and the lymph nodes of the bifurcation are located inferiorly.

Let’s start with the trachea (trachea)

ТTrachea (trachea)
ТTrachea (trachea)
Trachea (trachea)
Trachea (trachea)

It is divided into two main bronchi, namely the left bronchus (bronchus principalis sinister)

Left main bronchus (bronchus principalis sinister)
Left main bronchus (bronchus principalis sinister)
Left main bronchus (bronchus principalis sinister)
Left main bronchus (bronchus principalis sinister)

and the right bronchus (bronchus principalis dexter)

Right main bronchus (bronchus principalis dexter)
Right main bronchus (bronchus principalis dexter)
Right main bronchus
(bronchus principalis dexter)
Right main bronchus<br />
(bronchus principalis dexter)

At the level of the 5th thoracic vertebra, they flow into the right and left lungs in the area of their hilum (hilum pulmonis).

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

The root of the lung (radix pulmonis).

It consists of the main bronchus, pulmonary artery, two pulmonary veins, bronchial arteries and veins, lymphatic vessels, and nerves. In the right lung, going from top to bottom, lie the main bronchus, right pulmonary artery, and pulmonary veins (BAV).

Right main bronchus
Right main bronchus
Right main bronchus
Right main bronchus
Right main bronchus
Right main bronchus

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 pulmonary artery
Left pulmonary artery
Left pulmonary artery
Left pulmonary artery

Skeletotopy: the roots of the lung are located at the level between the 5th and the 7th thoracic vertebrae

Syntopy: the azygos vein, which passes from behind forward, the left bronchus and the arch of the aorta circumflex the root of the right lung superiorly, while the descending aorta, the esophagus, and the left vagus nerve circumflex it posteriorly.

Their structure is similar to that of the trachea, except that their cartilaginous rings are almost completely closed.

The mucous membrane of the main bronchi is a continuation of the mucous membrane of the trachea and consists of the ciliated epithelium.

The bronchial tree consists of the following structures:

  1. Main bronchi
  2. Extrapulmonary lobar bronchi
  3. Intrapulmonary lobar bronchi
  4. Segmental bronchi
  5. Subsegmental bronchi
  6. Interlobular bronchi
  7. Terminal lobular bronchioles
  8. Terminal bronchioles
  9. Primary respiratory bronchioles
  10. Secondary respiratory bronchioles
  11. Tertiary respiratory bronchioles
  12. Alveolar ducts
  13. Alveolar sacs and alveoli

The right main bronchus (bronchus principitalis dexter) is a direct continuation of the trachea. Therefore, foreign bodies from the trachea usually fall into its lumen. Its length is 3 cm, and its diameter is up to 2.5 cm. It is wider and shorter than the left bronchus.

Right main bronchus (bronchus principitalis dexter)
Right main bronchus (bronchus principitalis dexter)
Right main bronchus (bronchus principitalis dexter)
Right main bronchus (bronchus principitalis dexter)
Right main bronchus (bronchus principitalis dexter)
Right main bronchus (bronchus principitalis dexter)

The azygos vein, pulmonary artery, and aortic arch adhere to the right bronchus.

Each bronchus, starting from the main one, divides and decreases in diameter. The right bronchus divides into three large lobar bronchi, namely the superior lobar bronchus (bronchus lobaris superior)

Superior lobar bronchus (bronchus lobaris superior)
Superior lobar bronchus (bronchus lobaris superior)
Superior lobar bronchus (bronchus lobaris superior)
Superior lobar bronchus (bronchus lobaris superior)

the middle lobar bronchus (bronchus lobaris medius)

Middle lobar bronchus (bronchus lobaris medius)
Middle lobar bronchus (bronchus lobaris medius)
Middle lobar bronchus (bronchus lobaris medius)
Middle lobar bronchus (bronchus lobaris medius)

and the inferior lobar bronchus (bronchus lobaris inferior), which correspond to the lobes of the right lung.

Inferior lobar bronchus (bronchus lobaris inferior)
Inferior lobar bronchus (bronchus lobaris inferior)
Inferior lobar bronchus (bronchus lobaris inferior)
Inferior lobar bronchus (bronchus lobaris inferior)

The left main bronchus (bronchus principitalis sinister) is longer and narrower than the right one. It is virtually a branch of the trachea. Its length averages 6 cm, and its diameter rarely exceeds 1.5 cm.

Left main bronchus (bronchus principitalis sinister)
Left main bronchus (bronchus principitalis sinister)
Left main bronchus (bronchus principitalis sinister)
Left main bronchus (bronchus principitalis sinister)
Left main bronchus (bronchus principitalis sinister)
Left main bronchus (bronchus principitalis sinister)

It divides into two lobar bronchi: the superior lobar bronchus (bronchus lobaris superior)

Superior lobar bronchus (bronchus lobaris superior)
Superior lobar bronchus (bronchus lobaris superior)
Superior lobar bronchus (bronchus lobaris superior)
Superior lobar bronchus (bronchus lobaris superior)

and the inferior lobar bronchus (bronchus lobaris inferior), which correspond to the superior and inferior lobes of the left lung.

Inferior lobar bronchus (bronchus lobaris inferior)
Inferior lobar bronchus (bronchus lobaris inferior)
Inferior lobar bronchus (bronchus lobaris inferior)
Inferior lobar bronchus (bronchus lobaris inferior)

The aortic arch adheres to the left main bronchus anteriorly. It circumflexes it from front to back. Also, the esophagus and vagus nerve adhere to the posterior surface.

Lobar bronchi divide into segmental bronchi (bronchi segmentales), which correspond to the anatomical structures of the lungs called segments. They also belong to the large bronchi and have their own names.

Segmental bronchi (bronchi segmentales)
Segmental bronchi (bronchi segmentales)

The following segmental bronchi arise from the right superior lobar bronchus:

1. The apical segmental bronchus

Apical segmental bronchus (bronchus segmentalis apicalis)
Apical segmental bronchus (bronchus segmentalis apicalis)

2. The posterior segmental bronchus

Posterior segmental bronchus (bronchus segmentalis posterior)
Posterior segmental bronchus (bronchus segmentalis posterior)

3. The anterior segmental bronchus

Anterior segmental bronchus (bronchus segmentalis posterior)
Anterior segmental bronchus (bronchus segmentalis posterior)

From the middle right lobar bronchus:

1. The lateral segmental bronchus

Lateral segmental bronchus (bronchus segmentalis lateralis)
Lateral segmental bronchus (bronchus segmentalis lateralis)

2. The medial segmental bronchus

Medial segmental bronchus (bronchus segmentalis medialis)
Medial segmental bronchus (bronchus segmentalis medialis)

From the inferior right lobar bronchus:

  1. The apical segmental bronchus
  2. The medial basal segmental bronchus
Medial basal segmental bronchus (bronchus segmentalis basalis medialis)
Medial basal segmental bronchus (bronchus segmentalis basalis medialis)

3. The anterior basal segmental bronchus

Anterior basal segmental bronchus (bronchus segmentalis basalis anterior)
Anterior basal segmental bronchus (bronchus segmentalis basalis anterior)

4. lateral basal segmental bronchus

Lateral basal segmental bronchus (bronchus segmentalis basalis lateralis)
Lateral basal segmental bronchus (bronchus segmentalis basalis lateralis)

5. The posterior basal segmental bronchus

Posterior basal segmental bronchus (bronchus segmentalis basalis posterior)
Posterior basal segmental bronchus (bronchus segmentalis basalis posterior)

The following segmental bronchi arise from the left superior lobar bronchus:

1. The apical segmental bronchus

Apical segmental bronchus (bronchus segmentalis apicalis)
Apical segmental bronchus (bronchus segmentalis apicalis)

2. The posterior segmental bronchus

3. The anterior segmental bronchus

Anterior segmental bronchus (bronchus segmentalis anterior)
Anterior segmental bronchus (bronchus segmentalis anterior)

4. The superior lingular segmental bronchus

Superior lingular segmental bronchus (bronchus lingularis superior)
Superior lingular segmental bronchus (bronchus lingularis superior)

5. The inferior lingular segmental bronchus

Inferior lingular segmental bronchus (bronchus lingularis inferior)
Inferior lingular segmental bronchus (bronchus lingularis inferior)

From the inferior lobar bronchus:

1. The apical segmental bronchus

Apical segmental bronchus (bronchus segmentalis apicalis)
Apical segmental bronchus (bronchus segmentalis apicalis)

2. The medial basal segmental bronchus

Medial basal segmental bronchus (bronchus segmentalis basalis medialis)
Medial basal segmental bronchus (bronchus segmentalis basalis medialis)

3. The anterior basal segmental bronchus

Anterior basal segmental bronchus (bronchus segmentalis basalis anterior)
Anterior basal segmental bronchus (bronchus segmentalis basalis anterior)

4. The lateral basal segmental bronchus

Lateral basal segmental bronchus (bronchus segmentalis basalis lateralis)
Lateral basal segmental bronchus (bronchus segmentalis basalis lateralis)

5. The posterior basal segmental bronchus

Posterior basal segmental bronchus (bronchus segmentalis basalis posterior)
Posterior basal segmental bronchus (bronchus segmentalis basalis posterior)

Segmental bronchi, in turn, divide into medium-caliber bronchi, which are called subsegmental bronchi (bronchi subsegmentales). They are intermediate bronchi and divide into small interlobular bronchi (bronchi interlobulares).

At this level, the bronchi divide into bronchioles, which are the final branches of the bronchial tree. Their walls are thin, and do not contain cartilaginous laminae.

The preterminal bronchioles are intermediate branches between the bronchi and the terminal bronchioles.

The terminal bronchioles give off the terminal branches of the bronchial tree and form the so-called primary, secondary, and tertiary respiratory bronchioles.

Three alveolar ducts arise from each respiratory bronchiole, which in turn form alveolar sacs (sacculi alveolares) at their ends

Alveolar sacs (sacculi alveolares)
Alveolar sacs (sacculi alveolares)

And the sacs consist of alveoli, which are covered from the inside with a special substance called surfactant that prevents the alveoli from collapsing and sticking together, maintaining their surface tension.

Alveoli (alveoli)
Alveoli (alveoli)
Dictionary

Anatomy of the bronchial tree

Main bronchus
bronchus principalis
Hilum of the lung
hilum pulmonis
Right main bronchus
bronchus principalis dexter
Superior, middle, and inferior lobar bronchi
bronchi lobares superior, medius et inferior
Segmental bronchi
bronchi segmentales
Subsegmental bronchi
bronchi subsegmentales
Interlobular bronchi
bronchi interlobulares
Terminal bronchioles
bronchioles preterminales
Terminal bronchioles
bronchioles terminals
Respiratory bronchioles
bronchioles respiratorius
Alveolar sacs
sacculi alveolares
Alveoli
alveoli
Pulmonary alveoli
alveoli pulmonales
Left main bronchus
bronchus principalis sinister
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