The diaphragm, located below the lungs, is the major muscle of
respiration. It is a large, dome-shaped muscle that contracts
rhythmically and continually, and most of the time, involuntarily.
Upon inhalation, the diaphragm contracts and flattens and the chest
cavity enlarges. This contraction creates a vacuum, which pulls air
into the lungs. Upon exhalation, the diaphragm relaxes and returns
to its domelike shape, and air is forced out of the lungs.
Review Date: 05/25/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of
General Medicine, Department of Medicine, University of Washington
School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical
Director, A.D.A.M., Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
