Published ahead of print on May 28, 2003, doi:10.1164/rccm.200208-876OC
© 2003 American Thoracic Society Sex Differences in Thoracic Dimensions and ConfigurationResearch Center and Departments of Pneumology and Anesthesiology, Hôtel-Dieu du CHUM, Montréal, PQ, Canada Correspondence and requests for reprints should be addressed to François Bellemare, Ph.D., Centre de Recherche, CHUM-Hôtel-Dieu, 3850 St-Urbain Montréal, PQ, Canada H2W 1T7. E-mail: francois.bellemare{at}umontreal.ca The volume of adult female lungs is typically 10–12% smaller than that of males who have the same height and age. In this study, we investigated how this volume difference is distributed between the rib cage and the diaphragm abdomen compartments. Internal rib cage dimensions, diaphragm position relative to spine, and diaphragm length were compared in 21 normal male and 19 normal female subjects at three different lung volumes using anterior–posterior and lateral chest radiographs. At all lung volumes examined, females had smaller radial rib cage dimensions in relationship to height than males, a greater inclination of ribs, a comparable diaphragm dome position relative to the spine, and a shorter diaphragm length. Female subjects exhibited a greater inspiratory rib cage muscle contribution during resting breathing than males, presumably reflecting an improved mechanical advantage conferred to these muscles by the greater inclination of ribs. Because of a greater inclination of ribs, female rib cages could accommodate a greater volume expansion. The results suggest a disproportionate growth of the rib cage in females relative to the lung, which would be well suited to accommodate large abdominal volume displacements as in pregnancy.
Key Words: chest wall • lung size • sex • rib cage • diaphragm This article has been cited by other articles:
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