Percussion is a technique used during a clinical examination to elicit sounds while tapping on the body surface. These sounds can give clues to physicians as to the state of the underlying structures. Percussion can be utilized during well checks or during development of the physician’s differential diagnosis. Percussion was introduced to distinguish between empty and filled barrels of liquor until Dr. Leopold Auenbrugger introduced the technique to medicine.
How the Method is Performed
The physician will take the middle finger of one hand and tap on the middle finger of the other hand using a wrist action. The non-striking fingers are placed firmly over the area of examination. When percussing boney areas such as the clavicle the non-striking hand can be omitted and the bone is tapped directly.
What is Heard
This technique elicits four types of sound that give answers to the physician. Resonant, hyper-resonant, stony dull or dull sounds mean different things in different parts of the body. A resonant sound is indicative of hollow or air-containing structures. In a case where a physician was trying to determine if a hollow organ was infected, they could percuss to listen for resonant sounds. If there was a non-resonant sound, then the hollow organ could be filled with infection byproduct. A dull sound could indicate the presence of a solid mass under the surface. Each sound has different tones so it is not just to see whether the sound is present or not.
Listening Section by Section
Percussion of the chest wall is used to diagnose pneumothorax, emphysema, trauma damage, and many other diseases. Hyper-resonance might indicate bleeding in areas where it should be hollow.
Percussion of the abdomen can give different tones that outline the organs. This is used to find whether any organ is enlarged or tender.