Morphometric variability of the human upper bronchial tree.

Available morphometric models of the human tracheobronchial tree are based on measurements of a small number of individuals from a few laboratories. In order to determine the degree of intersubject variability, and its relationship to intrasubject variability, analysis of airway lengths, diameters and branching angles was performed using solid casts of the upper bronchial trees from a series of human lungs. The results indicate that there are significant differences between subjects. Inter- and intrasubject variabilities should be considered in occupational and environmental hazard evaluation, and when extrapolating and modeling inhalation toxicologic data.