Posterior Segmental Artery of the Left Lung, Anterior View

Description

Arising from the left pulmonary artery, the posterior segmental artery (A2) tracks laterally and posteriorly toward the superior lobe of the left lung, running in close company with the posterior segmental bronchus (B2) and the accompanying pulmonary veins that course more anterior and inferior in the intersegmental planes. From an anterior perspective, the vessel’s origin is appreciated near the pulmonary trunk bifurcation, with the left main bronchus lying posterior to the pulmonary artery and the left atrium positioned posteriorly as the venous confluence returns via the left superior pulmonary vein. Proximal cardiac structures, including the right and left ventricles, atria, and the ascending aorta, provide fixed landmarks that clarify how the pulmonary circulation arches toward the hilum while the trachea and main bronchi remain superior and posterior. Segmental arterial anatomy matters when you are trying to divide the left upper lobe along anatomical, rather than arbitrary, planes. During VATS segmentectomy of the posterior segment (S2), identifying A2 at the hilum and following it distally helps separate arterial branches from adjacent A1 and A3 branches, reducing the risk of leaving an ischemic remnant or injuring an intersegmental vein that marks the true boundary. It also supports interpretation of CT pulmonary angiography when emboli or congenital variants alter expected branching patterns. Small branch, high consequence. Ideal use cases include thoracic surgery atlases illustrating left upper lobe segmentectomy, radiology teaching files correlating bronchopulmonary segments with pulmonary arterial branches, and cardiopulmonary anatomy modules that integrate the heart, pulmonary arteries, pulmonary veins, trachea, and bronchi in one coherent anterior view. Anatomical accuracy verified by SciePro's Medical Advisory Board.