Percussion

Overview
Percussion is a method used by a healthcare provider to find out about the changes in the thorax or abdomen. It is done by tapping on a surface to determine the underlying structure. It is one of the four methods of clinical examination: inspection (medicine), palpation, percussion and auscultation. It is done with the middle finger of right hand tapping on the middle finger of the left hand, which is positioned with the whole palm on the body.

There are two types of percussion: direct percussion, which uses only 1 or two fingers, and indirect percussion, utilizing the middle/flexor finger. The method was initially used to distinguish between empty and filled barrels of liquor.

There are four different percussion sounds:


 * Sonorous
 * Hypersonorous
 * Relatively dull sound
 * Completely dull sound

The presence of a solid mass underneath the surface will produce a dull sound. Hollow, air-containing structures will lead to a more sonore sound.

Percussion of the thorax
It is used to diagnose pneumothorax, emphysema and other diseases. It can be used to access the respiratory mobility of the thorax.

Differential Diagnosis of Abnormalities in Percussion of the Lung
In alphabetical order:

Dullness

 * Foreign body
 * Lobar pneumonia
 * Lung abscess
 * Lung tumor
 * Pleural Effusion
 * Pleural tumor
 * Pulmonary edema
 * Pulmonary infarction
 * Tuberculosis infiltrate
 * Tumor

Flatness

 * Large Pleural Effusion

Resonance

 * Chronic Bronchitis

Hyperresonance

 * Emphysema
 * Pneumothorax
 * Status asthmaticus

Tympany

 * Intestinal loop
 * Large pneumothorax
 * Lung caverns
 * Lung cyst

Percussion of the abdomen
It is used to find whether any organ is enlarged and similar. It is based on the principle of setting tissue and spaces in between at vibration. The sound thus generated is used to determine if the tissue is healthy or pathological.