Vessel
Pulmonary veins
Return pathway from lung capillaries to the left atrium
High-yield
The right middle lobe usually drains through the right superior pulmonary vein. Four atrial openings are common, but counting four is not a reliable rule for every person.
Overview
Pulmonary venous tributaries gather blood after gas exchange and converge toward the lung roots. The usual arrangement has a superior and an inferior vein on each side opening into the left atrium. Common trunks and additional veins are normal anatomical variants.
Reference facts
- Origin
- Venules collecting blood from pulmonary capillaries
- Course
- Tributaries converge at each hilum; the superior vein is anterior and the inferior vein occupies the lower part of the root
- Branches
- Intersegmental tributaries; the right middle lobe commonly joins the superior vein, while separate ostia or a shared left trunk may occur
- Supplies
- No arterial supply territory: these vessels return oxygenated pulmonary blood
- Drains to
- Left atrium, most often through four openings in its posterior region
Clinical correlation
Myocardial sleeves extending into pulmonary veins can generate impulses that initiate atrial fibrillation. Partial anomalous return to a systemic vein recirculates some oxygenated blood through the right heart, producing a left-to-right shunt.
Frequently asked questions
Where do the pulmonary veins originate?
The pulmonary veins arise from the venules collecting blood from pulmonary capillaries.
What do the pulmonary veins supply?
No arterial supply territory: these vessels return oxygenated pulmonary blood.
Where do the pulmonary veins drain to?
The pulmonary veins drain to the left atrium, most often through four openings in its posterior region.
What are the branches of the pulmonary veins?
Intersegmental tributaries; the right middle lobe commonly joins the superior vein, while separate ostia or a shared left trunk may occur.