Inferior lobar artery of right lung

Caudal to the origin of the right middle lobe arteries, the interlobar artery becomes the right lower lobe artery. At about the same level as the origin of the right middle lobe arteries and opposite to them, the right lower lobe artery gives off the posteriorly oriented artery to the superior (apical) segment of the right lower lobe (A6).

However, in approximately 20% of individuals, A6 arises as two or very rarely three separate arteries from the right lower lobe artery.

Caudal to the origin of the artery to the superior segment of the right lower lobe, the right lower lobe artery is renamed as the pars basalis, or basal trunk.

In approximately one-half of individuals, the order of branching from the pars basalis is first the medial basal segmental artery (A7), then the anterior basal segmental artery (A8), and finally the lateral and posterior basal segmental arteries (A9 and A10).

An inconstant subsuperior pulmonary segment is seen in approximately 30% of individuals, located between the superior and basal segments of the lower lobes bilaterally (7). If present, its pulmonary arterial supply is denoted as A8 or A*, and this artery generally takes origin from the lateral aspect of the right pars basalis. It has a single stem in the majority of cases, although two and three stems are sometimes seen. 

Branches of right lower lobe artery:

• Basal part (basal trunk)

• Superior segmental artery of right lung (A6)

• Anterior basal segmental artery of right lung (A7)

• Lateral basal segmental artery of right lung (A8)

• Medial basal segmental artery of right lung (A9)

• Posterior basal segmental artery of right lung (A10)