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Morphometry of Airways

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Abstract

The sections in this article are:

1 Definitions and Properties of Trees
2 Techniques of Airway Casting
2.1 Inflation
2.2 Fixation
2.3 Filling Pressure
2.4 Casting Material
3 Human Airway Morphometry
3.1 Definitions
3.2 Conducting Airways
3.3 Number of Conducting Airways
3.4 Variability of Airway Dimensions
3.5 Morphometric Parameters
3.6 Intra‐acinar Airways
3.7 Bifurcations
3.8 Branching Angle
3.9 Diameter Ratios
4 Determinants of Airway Size and Shape
4.1 Diameter Ratios, Length Ratios, and Branching Ratios
4.2 Branching Angles
5 Models of Airways
5.1 Symmetrical Model With Connectivity
5.2 Symmetrical Model Without Connectivity
5.3 Asymmetrical Models With Connectivity
5.4 Asymmetrical Models Without Connectivity
5.5 Merits and Demerits of the Models
6 Conclusion
Figure 1. Figure 1.

Terminology in branching trees. A, B, C: nodes and links in dichotomous branching. D: monopodial branching. E: generations in a symmetrical tree. F: generations in an asymmetrical tree. G: Horsfield orders in a symmetrical tree. H: Horsfield orders in an asymmetrical tree. I: Strahler orders, stage 1. J: Strahler orders, stage 2. K: symmetrical branching, delta = 0. L: asymmetrical branching, delta = 1. M: asymmetrical branching, delta = 4.

Figure 2. Figure 2.

Number, mean diameter, and mean length of branches in each Strahler order of a cast of the human bronchial tree. Straight lines represent the regression equations.

Figure 3. Figure 3.

Number, mean diameter, and mean length of branches in each Horsfield order of a cast of the human bronchial tree (same cast as in Fig. ). Straight lines represent the regression equations.

Figure 4. Figure 4.

Branching patterns in human pulmonary acini. A: Weibel's models. For simplicity only 1 alveolar duct system is shown. B: model from Ogawa . C: model from Parker, Horsfield, and Cumming . D: model from Hansen et al. . E: model from Pump . TB, terminal bronchiole; RBI, first‐generation respiratory bronchiole; AD1, first‐generation alveolar duct; ○, incomplete structure.



Figure 1.

Terminology in branching trees. A, B, C: nodes and links in dichotomous branching. D: monopodial branching. E: generations in a symmetrical tree. F: generations in an asymmetrical tree. G: Horsfield orders in a symmetrical tree. H: Horsfield orders in an asymmetrical tree. I: Strahler orders, stage 1. J: Strahler orders, stage 2. K: symmetrical branching, delta = 0. L: asymmetrical branching, delta = 1. M: asymmetrical branching, delta = 4.



Figure 2.

Number, mean diameter, and mean length of branches in each Strahler order of a cast of the human bronchial tree. Straight lines represent the regression equations.



Figure 3.

Number, mean diameter, and mean length of branches in each Horsfield order of a cast of the human bronchial tree (same cast as in Fig. ). Straight lines represent the regression equations.



Figure 4.

Branching patterns in human pulmonary acini. A: Weibel's models. For simplicity only 1 alveolar duct system is shown. B: model from Ogawa . C: model from Parker, Horsfield, and Cumming . D: model from Hansen et al. . E: model from Pump . TB, terminal bronchiole; RBI, first‐generation respiratory bronchiole; AD1, first‐generation alveolar duct; ○, incomplete structure.

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How to Cite

Keith Horsfield. Morphometry of Airways. Compr Physiol 2011, Supplement 12: Handbook of Physiology, The Respiratory System, Mechanics of Breathing: 75-88. First published in print 1986. doi: 10.1002/cphy.cp030307