Left Pulmonary Veins

The pulmonary veins carry oxygen-rich blood from the lungs to the left atrium. There are four pulmonary veins, two for each lung. The two pairs of pulmonary veins, superior and inferior, are located in the thorax. The left and right pulmonary veins originate from the left and right lungs respectively. Averaging 15 mm in length and 15 mm in diameter, they are valveless, with all four pulmonary veins running horizontally towards the posterior part of the left atrium. This path is slightly inclined downwards in the case of the superior veins. They pass through the fibrous pericardium, where they are partially covered by serosa, and terminate individually in the left atrium.