Left inferior pulmonary vein
Vena pulmonalis sinistra inferior
Definition
The left inferior pulmonary vein is one of the four major pulmonary veins that drains oxygenated blood from the left lung into the posterior wall of the left atrium. It collects blood from the lower lobe of the left lung and enters the left atrium through an oval-shaped ostium located on the posteroinferior aspect of the chamber.
In the typical anatomical pattern (present in approximately 71-86% of individuals), the left inferior pulmonary vein exists as a separate vessel with its own distinct ostium entering the left atrium, formed by the confluence of:
The mean ostial diameter is approximately 13.3-14.8 mm, making it the smallest of the four major pulmonary veins. The ostium surface area averages 136 mm², which is significantly smaller than the other pulmonary vein ostia.
The vein has a relatively short course from its ostium to its first tributary branch, averaging 13.5 mm, which is longer than the right inferior pulmonary vein but shorter than the superior pulmonary veins. The left inferior pulmonary vein is typically positioned more superior than the right inferior pulmonary vein. On the left side, the mean distance between the superior and inferior pulmonary veins is approximately 4.02 mm.
An important anatomical variant occurs in approximately 4-14% of cases, where the left superior and left inferior pulmonary veins share a common ostium (common left pulmonary vein trunk) before entering the left atrium.
The vein is surrounded by myocardial sleeves that extend from the left atrium onto the venous wall, which are clinically significant as they can serve as sources of ectopic electrical activity triggering atrial fibrillation.
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