Pulmonary trunk and its branch

The pulmonary trunk (truncus pulmonalis) 30 mm in diameter emerges from the right ventricle of the heart, from which it is delimited by its valve. The beginning of the pulmonary trunk and, accordingly, its opening is projected onto the anterior thoracic wall above the site of attachment of cartilage III of the left rib to the sternum. The pulmonary trunk is located anterior to the other major vessels of the heart base (the aorta and the superior vena cava). On the right and behind it is the ascending part of the aorta, and to the left is the left ear of the heart. The pulmonary trunk located in the pericardial cavity is guided in front of the aorta to the left and back and at level IV of the thoracic vertebra (cartilage II of the left rib) is divided into the right and left pulmonary arteries. This place is called the bifurcation of the pulmonary trunk (bifurcdtio trunci pulmonalis). Between the bifurcation of the pulmonary trunk and the arch of the aorta is a short arterial ligament (ligamentum arteriosum), which is a overgrown arterial (botfull) duct (ductus arteriosus).

The right pulmonary artery (a.pulmonalis dextra) with a diameter of 21 mm should be to the right to the gates of the right lung behind the ascending part of the aorta and the terminal section of the superior vena cava and anterior to the right bronchus. In the area of the gates of the right lung in front and under the right main bronchus, the right pulmonary artery is divided into three lobar branches. Each lobar branch in the corresponding lobe of the lung is in turn divided into segmental branches. In the upper lobe of the right lung, the apical branch (r.apicalis), the posterior descending and ascending branches (rr.posteriores descendens et ascendens), the forward descending and ascending branches (rr.anteriores descendens et ascendens) that follow in the apical, posterior and anterior segments of the right lung.

The branch of the middle lobe (rr.lobi medii) is divided into two branches - lateral and medial (r.lateralis et r.medialis).

These branches go to the lateral and medial segments of the middle lobe of the right lung. The branches of the lower lobe (rr.lobi inferioris) include the upper (apical) branch of the lower lobe [r.superior (apicalis) lobi inferioris], directed towards the apical segment (upper) segment of the lower lobe of the right lung, and the basal part (pars basalis). The latter is divided into 4 branches: medial, anterior, lateral and posterior (rr.basales medialis, anterior, lateralis and posterior). They carry blood into the same basal segments of the lower lobe of the right lung.

The left pulmonary artery (a.pulmonalis sinistra) is shorter and thinner than the right, passes from the bifurcation of the pulmonary trunk along the shortest path to the gates of the left lung in the transverse direction in front of the descending part of the aorta and the left bronchus. On its way, the artery crosses the left main bronchus, and at the gates of the lung is located above it. Corresponding to two parts of the left lung, the pulmonary artery is divided into two branches. One of them breaks down into segmental branches within the upper lobe, the second - the basal part - with its branches blood supply segments of the lower lobe of the left lung.

To the segments of the upper lobe of the left lung, the branches of the upper lobe (rr.lobi superioris), which give the apical branch (r.apicalis), the front ascending and descending (rr.anteriores ascendens et descendens), the posterior (r.posterior) and the ligulum (r .lingularis) branches. The upper branch of the lower lobe (r.superior lobi inferioris), as in the right lung, follows the lower lobe of the left lung, to its upper segment. The second share branch - the basal part (pars basalis) is divided into four basal segmental branches: medial, lateral, anterior and posterior (rr.basales medialis, lateralis, anterior and posterior), which branch out in the corresponding basal segments of the lower lobe of the left lung.

In the lung tissue (under the pleura and in the region of respiratory bronchioles) small branches of the pulmonary artery and bronchial branches extending from the thoracic part of the aorta form systems of interarterial anastomoses. These anastomoses are the only place in the vascular system in which blood circulation can be made along a short path from the large circle of the circulation directly to the small circle.

[1], [2], [3]