Side branches of the pulmonary artery in the hilar region.

The pulmonary air space between the large bronchi at the hilum is supplied by small daughter bronchi that stem from axial main branches. In this study, we evaluated the morphological appearance of the pulmonary artery which corresponds to the daughter bronchus using an inflated-fixed lung specimen. In contrast to the relationship in the subpleural area, the pulmonary artery did not follow the corresponding airway in the area supplied by the daughter bronchus. Only at the tip of the terminal bronchiole was a close association found. Each terminal bronchiole showed a tendency to receive its blood supply from the nearest parent branch of the pulmonary artery.