X-rays of the abdomen are important in diagnosing the presence of small bowel obstruction. When obstruction occurs, both fluid and gas collect in the intestine. They produce a characteristic pattern called "air-fluid levels". The air rises above the fluid and there is a flat surface at the "air-fluid" interface.
Review Date 5/4/2022
Updated by: Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.