Anterior basal segmental artery of right lung

The anterior basal segmental artery of the right lung (A8), is a branch of the Inferior lobar artery of right lung that supplies the anterior basal segment (S8) of the right lower lobe.

Origin and course

The right main pulmonary artery divides at the hilum into a superior trunk (truncus anterior) and an inferior trunk (interlobar artery). The interlobar artery descends within the oblique fissure alongside the bronchus intermedius and, after giving off branches to the middle lobe and the superior segment (A6) of the lower lobe, continues as the basal trunk. From this basal trunk, A8 arises as one of the basal segmental arteries typically alongside the medial basal (A7), lateral basal (A9), and posterior basal (A10) arteries. A8 courses anteriorly and inferiorly, closely accompanying the anterior basal segmental bronchus (B8), to supply the anterior basal segment of the right lower lobe.

Anatomical relationships

Within the segment, the artery generally lies toward the lung periphery relative to its corresponding bronchus (i.e., anterior or lateral to B8), while the segmental veins run more centrally (posterior or medial to the bronchus), draining into the inferior pulmonary vein. The segmental artery closely accompanies the segmental bronchus in approximately 90% of pulmonary segments. Anatomical variations in the basal segmental arteries are common, occurring in up to 20% of cases; A8 may be single, duplicated, or even triplicated, and may share a common trunk with A7 or other basal segmental arteries.