20. 



LUNG WEIGHT AND VOLUME INCREMENTS DURING FIRST YEAR: MAN 

 Figures in parentheses are total number of observations. 



P g 



O 

 > 



275 



250 



225 



200 



175 



150 



125 



100 



75 



50 



25 







E3 Lung weight (600) 

 CH Lung volume (360) 



^ 



Birth 



^ 



2-3 



3-6 

 Month 



9-12 



Reference : Krogman. W. M. , Tabulae Biologicae 20:669, 1941 (adapted from Scammon, R. E., Radiology 9:101 , 1927). 



21. DIMENSIONS OF TRACHEOBRONCHIAL TREE: MAN, ADULT 



Values tabulated below represent average dimensions of the adult tracheobronchial tree, computed by Findeisen and 

 Landahl, according to a functional concept of structure rather than a strictly anatomical description. Here, the 

 major bronchi are listed according to their order of generation rather than to lobar or segmental distribution. This 

 table serves two purposes: First, it permits listing bronchi of similar size in the same category, and second, it 

 serves as a tool for the functional description of airflow characteristics at various points of the tracheobronchial 

 tree. However, the user of these values must recognize that there is considerable overlapping of the various 

 orders of branching. 



Contributor : Ross, B. B. 



Referenc es: [ l] Findeisen, W., Pflugers Arch. 236:367, 1935. [2] Landahl, H. D., Bull. Math. Biophys. 12:43, 

 1950. 



22. DIAMETER OF RESPIRATORY ALVEOLI: MAN 

 Values are in millimeters. 



Contributor: Boyd, E. 



Reference : Scammon, R. E. 

 1923. 



'Pediatrics," (Abt, 1. A., ed.), vol I, p 257, Philadelphia: W. B. Saunders Co. 



17 



