Pulmonalvenen

Pulmonalvenen (pulmonary veins) are the vessels that drain oxygenated blood from the lungs back to the left atrium of the heart. In a typical adult, four main veins return blood from the lungs: the right superior, right inferior, left superior, and left inferior pulmonary veins. These veins are part of the pulmonary circulation, distinct from the pulmonary arteries, which bring deoxygenated blood to the lungs.

Anatomically, the pulmonary veins run within the bronchovascular bundles from the lungs toward the left atrium and merge into four ostia that open into the atrium. Variations are common: some individuals have additional accessory veins or different segmental drainage patterns. The veins generally lack valves along their course, but in some people small valve-like structures may be present near the ostia.

Embryology explains their typical arrangement. During development, a common pulmonary venous outflow connects with the left atrium and gradually incorporates the lung venous plexus. Failures or malformations of this process can result in congenital anomalies such as total anomalous pulmonary venous return (TAPVR), where pulmonary veins do not connect normally to the left atrium.

Clinical relevance includes conditions that affect the pulmonary veins or their drainage. Pulmonary vein stenosis, a narrowing of one or more veins, can cause pulmonary hypertension and right‑sided heart strain. Atrial fibrillation ablation procedures frequently target triggers near the pulmonary vein ostia, which can, in rare cases, lead to stenosis. Imaging modalities such as echocardiography, CT angiography, or MR angiography are used to assess vein anatomy and pathology, guiding diagnosis and treatment, which may involve catheter-based or surgical approaches depending on the condition.