The 'pulmonary veins' carry
oxygen-rich
blood from the
lungs to the left
atrium of the
heart. They are the only
veins in the post-
fetal human body that carry oxygenated (red) blood.
The pulmonary veins return the oxygenated blood from the
lungs to the
left atrium of the
heart.
Types
They are four in number, two from each lung, and are destitute of
valves. They are
★ right inferior
★ right superior
★ left inferior
★ left superior
Path
They commence in a
capillary net-work upon the walls of the
air sacs, where they are continuous with the capillary ramifications of the
pulmonary artery, and, joining together, form one vessel for each
lobule.
These vessels uniting successively, form a single trunk for each lobe, three for the right, and two for the left lung.
The vein from the middle lobe of the right lung generally unites with that from the upper lobe, so that ultimately two trunks from each lung are formed; they perforate the fibrous layer of the
pericardium and open separately into the upper and back part of the
left atrium.
Occasionally the three veins on the right side remain separate.
Not infrequently the two left pulmonary veins end by a common opening.
At the root of the lung, the superior pulmonary vein lies in front of and a little below the pulmonary artery; the inferior is situated at the lowest part of the
hilus of the lung and on a plane posterior to the upper vein. Behind the pulmonary artery is the
bronchus.
Within the
pericardium, their anterior surfaces are invested by the serous layer of this membrane.
The right pulmonary veins pass behind the
right atrium and
superior vena cava; the left in front of the descending
thoracic aorta.
Additional images
External links
★
★
Illustration at infomat.net