Percussion is a method of tapping body parts with fingers, hands, or small instruments as part of a physical examination. The purpose is to evaluate the size, consistency, and borders of body organs, and the presence or absence of fluid in body areas.
Percussion of a body part produces a sound -- like playing a drum -- that indicates the type of tissue within the body part or organ:
Lungs sound hollow on percussion because they are filled with air.
Bones, joints, and solid organs such as the liver sound solid.
The abdomen sounds like a hollow organ filled with air, fluid, or solids.
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.