Subepithelial Superficial Lymph Vessels in the Airway: A Histological Study Using Human Fetuses and Elderly Cadavers

This histological study examined the morphology of lymph vessels (LVs) in the airways using specimens from 20 cadavers and 10 human fetuses. The study found that LVs exhibited site-dependent differences, with the highest density in the upper pharynx and the lowest at the mucocutaneous junction of the nose. In the nose, ciliated epithelia had a denser network of LVs compared to squamous epithelia. However, site-dependent specificity, particularly in the pharynx, overshadowed epithelial type-dependent differences. In fetuses, distinct site-dependent features were observed, such as a well-developed venous plexus in the nasal wall and palate, which might affect LV development. After birth, these site-dependent differences in LVs appeared to change significantly based on functional demands, making epithelia-dependent differences less clear.