Pulmonary vein
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left atrium of the heart. The pulmonary veins are part of the pulmonary circulation.
Pulmonary vein
venae pulmonales
Clinical significance[edit]
As part of the pulmonary circulation they carry oxygenated blood back to the heart, as opposed to the veins of the systemic circulation which carry deoxygenated blood. By definition, a vein is a blood vessel that carries blood to the heart, whether oxygenated or deoxygenated.
On chest X-ray, the diameters of pulmonary veins increases from upper to lower lobes, from 3 mm at the first intercoastal space, to 6 mm just above the diaphragm.[3]
A rare genetic defect of the pulmonary veins can cause them to drain into the pulmonary circulation in whole or in part, this is known as a total anomalous pulmonary venous connection (or drainage), or partial anomalous pulmonary connection, respectively.
Bronchial anatomy
Transverse section of thorax, showing relations of pulmonary artery.
Pulmonary vessels, seen in a dorsal view of the heart and lungs.
