A hiatal hernia occurs when part of the stomach protrudes up into the chest through the sheet of muscle called the diaphragm. This may result from a weakening of the surrounding tissues and may be aggravated by obesity and/or smoking.
Review Date 4/24/2017
Updated by: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.