Anterior segmental artery of right lung

The anterior segmental artery of the right lung (A3), is a branch of the right pulmonary artery that supplies the anterior segment (S3) of the right upper lobe.

Origin and course: The right pulmonary artery divides at the hilum into a superior trunk (also called the truncus anterior) and an inferior trunk (the interlobar artery). The truncus anterior is the first branch of the right pulmonary artery and typically gives rise to two segmental branches: the apical segmental artery (A1) and the anterior segmental artery (A3). The posterior segmental artery (A2) usually arises separately, distal to the truncus anterior.

Territory: A3 supplies the anterior segment of the right upper lobe (S3), which occupies the anterolateral portion of the upper lobe, extending from the hilum toward the anterior chest wall. This segment is bordered superiorly by the apical segment (S1) and posteriorly by the posterior segment (S2).

Anatomical variations: The branching pattern of the right upper lobe arteries is subject to considerable variation. In some individuals, A3 may arise independently from the right pulmonary artery rather than from the truncus anterior. Additional arterial supply to the anterior segment may come from ascending branches of the interlobar artery (so-called "recurrent" or "ascending anterior" arteries).