A proposed alveolar model for adult human lungs: the regular dodecahedron.

In an endeavor to delineate an alveolar configuration that would reasonably mirror the natural state, polygonal shapes of normal alveoli were tabulated in histological sections from inflation-fixed specimens of 16 men aged 16-48 years. The resulting alveolar population varied from three- to ten-sided polygons with a preponderance of tetragons, pentagons, and hexagons. These observations were compared with the possible combinations of polygonal sections through various polyhedral models proposed by other workers and the five classical regular polyhedrons. The potential types of sections through the regular dodecahedron, i.e., a twelve-sided shape with faces consisting of pentagons, seemed to fit best with present findings, and this is suggested as an idealized configuration that might be useful in various geometric determinations, e.g., estimates of alveolar surface area and volume.