The Juxta-Alveolar Lymphatics in the Human Adult Lung
The lymphatics of the human lung studied in 15 adults who died of drowning were unusually prominent and often dilated in histologic sections. Two main sets of lymphatics were distinguished in the adult lung: the superficial or pleural set and the deep or parenchymatous (peribronchovascular) lymphatic plexus. Regarding the disputed occurrence of alveolar lymphatics, a sharp distinction was made in this study between the air-blood barrier, the interalveolar septum, and the alveolar wall. No lymphatic capillaries were observed at the level of the air-blood barrier or the interalveolar septum, but characteristic lymphatic capillaries were present between the alveolar walls and the interlobular, pleural, peribronchial, or perivascular connective sheets. These were defined as “juxta-alveolar” lymphatic capillaries, because of their close topographic and probable functional relationship to the alveolar lumina without being a part of the interalveolar septa themselves. These lymphatics assist in the removal and c...