Pulmonary veins

From the capillaries of the lungs, venules begin, which merge into larger veins and form two pulmonary veins in each lung.

Of the two right pulmonary veins, the upper one has a larger diameter, since it drains blood from two lobes of the right lung (superior and middle). Of the two left pulmonary veins, the lower vein has a larger diameter. At the gates of the right and left lungs, the pulmonary veins occupy their lower part. In the posterior upper part of the root of the right lung is the main right bronchus, in front of and below it is the right pulmonary artery. At the left lung, the pulmonary artery is located above, and behind and below it is the left main bronchus. At the right lung, the pulmonary veins lie below the artery, follow almost horizontally and on their way to the heart are located behind the superior vena cava, the right atrium and the ascending part of the aorta. Both left pulmonary veins, which are somewhat shorter than the right ones, are located under the left main bronchus and are directed to the heart also in a transverse direction, in front of the descending part of the aorta. The right and left pulmonary veins, piercing the pericardium, flow into the left atrium (their terminal sections are covered by the epicardium).

The right superior pulmonary vein (v.pulmonalis dextra superior) collects blood not only from the upper, but also from the middle lobe of the right lung. From the upper lobe of the right lung, blood flows out through three veins (tributaries): apical, anterior and posterior. Each of them, in turn, is formed from the fusion of smaller veins: intrasegmental, intersegmental, etc. From the middle lobe of the right lung, blood flows out through the vein of the middle lobe (v.lobi medii), formed from the lateral and medial parts (veins).

The right inferior pulmonary vein (v.pulmonalis dextra inferior) collects blood from five segments of the lower lobe of the right lung: the superior and basal ones - medial, lateral, anterior and posterior. From the first of them, blood flows out through the superior vein, which is formed as a result of the fusion of two parts (veins) - intrasegmental and intersegmental. From all basal segments, blood flows out through the common basal vein, which is formed from two tributaries - the superior and inferior basal veins. The common basal vein, merging with the superior vein of the lower lobe, forms the right inferior pulmonary vein.

The left superior pulmonary vein (v.pulmonalis sinistra superior) collects blood from the upper lobe of the left lung (its apical-posterior, anterior, and also upper and lower lingual segments). This vein has three tributaries: the posteroapical, anterior, and lingual veins. Each of them is formed from the confluence of two parts (veins): the posteroapical vein - from the intrasegmental and intersegmental; the anterior vein - from the intrasegmental and intersegmental; and the lingual vein - from the upper and lower parts (veins).

The left inferior pulmonary vein (v.pulmonalis sinistra inferior) is larger than the right vein of the same name and carries blood from the lower lobe of the left lung. The superior vein branches off from the upper segment of the lower lobe of the left lung, which is formed by the fusion of two parts (veins) - intrasegmental and intersegmental. From all basal segments of the lower lobe of the left lung, as in the right lung, blood flows out through the common basal vein. It is formed by the fusion of the superior and inferior basal veins. The anterior basal vein flows into the upper one, which, in turn, merges from two parts (veins) - intrasegmental and intersegmental. As a result of the fusion of the superior vein and the common basal vein, the left inferior pulmonary vein is formed.

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