Cardiopulmonary dimensions: stability over a long period.

The transverse diameter of the heart, diameters of the basal arteries, lung height and width, and diaphragm level were measured from two radiographs obtained 10-34years apart in 100 normal subjects. No difference was found in basal artery diameters, lung height, or diaphragm level. Lung width increased slightly. Transverse diameter of the heart increased slightly (0.43 cm) but significantly. This increase was not related to the age of the subject and had a low linear correlation with the interval between radiographs. In eight subjects, the heart diameter increased by more than 1.5 cm. Age is not an important factor in judging heart size from the transverse diameter on chest radiographs.