Anterior trunk of right pulmonary artery

The anterior trunk of the right pulmonary artery (Truncus anterior; Superior trunk) is the first major branch of the right pulmonary artery. At the right lung hilum, the right pulmonary artery divides into two main trunks: the anterior trunk and the inferior trunk (interlobar artery). The truncus anterior courses anteriorly and superiorly and supplies the right upper lobe of the lung.

Branching pattern: The truncus anterior typically gives rise to the apical segmental artery (A1) and the anterior segmental artery (A3) of the right upper lobe. The posterior segmental artery (A2) usually arises separately, distal to the truncus anterior. The inferior trunk (interlobar artery) continues inferiorly, running parallel to the bronchus intermedius within the interlobar fissure, and supplies the middle and lower lobes.

This branching pattern is distinct from the left side, where the left main pulmonary artery does not divide into analogous superior and inferior trunks but rather continues as a single interlobar trunk, with a more variable branching pattern. On the left, the apical (A1) and posterior (A2) segments are often supplied by a common segmental artery (A1+2) arising directly from the left main pulmonary artery.

The difference between Anterior trunk of right pulmonary artery and Superior lobar artery of right lung may be unclear.