Percussion of the lungs, along with auscultation, is considered the most important method of clinical examination of patients with respiratory diseases. Percussion is still widely used in clinical practice, despite the emergence of new diagnostic methods of instrumental research.
The method of percussion or percussion was proposed by the Austrian physician Auenbrugger in 1761, and was introduced into clinical practice by the French physician Corvisar. Percussion of the lungs, like other organs, is carried out by hand, does not require the use of additional tools, is simple and highly informative.
The method is based on the fact that internal organs when tapping produce sounds of different heights. The qualities of these sounds, called percussion sounds, depend on the content and density of the organ tissue. During percussion of body parts that do not contain air, a dull percussion sound is formed. A similar sound is formed, for example, with percussion of the liver. When percussing organs containing a lot of air, the sound is sonorous. Thus, by a change in the percussion tone, one can judge the changes in the internal organs, their location.
Normally, a sonorous sound is determined over the entire surface of the lungs due to the high air content. This sound is called clear pulmonary. With the development of various diseases, the air content in the lungs can increase or decrease, and percussion sound changes accordingly.
Changes in percussion sound occur in the direction of blunting or in the direction of tympanitis, that is, an increase in voicing. The nature of the sound depends on the amount of air and the density of the underlying tissues.
Dullness of percussion sound occurs when collecting exudate in the pleural cavity, reducing the amount of air in the lung tissue due to pneumosclerosis, with the development of inflammation of various origins, the growth of the tumor.
An increase in voicing during percussion is observed when excess air is accumulated in the lungs, which happens with emphysema or bronchial asthma. High percussion sound is determined over large cavities in the lungs filled with air (tuberculous caverns, opened lung abscess , pneumothorax).
Topographic percussion of the lungs is used primarily for determining the boundaries of the lungs. First, the boundaries of the apices of the lungs are determined. Normally, the height of the tops is determined above both clavicles by 3-5 cm. Then they find the lower border, starting from the right half. With the expansion of the lungs, their lower border drops, and with a high standing of the diaphragm, which occurs during pregnancy, ascites, flatulence, on the contrary, rises. Topographic percussion of the lungs makes it possible to determine the respiratory excursion of the lungs, that is, their active mobility, which is the difference between the lower border of the lungs during maximum inhalation and exhalation. In healthy people, the lung excursion is 4-8 cm. In severe inflammatory processes in the lungs, emphysema, pleurisy, pneumosclerosis, lung excursion is reduced. This occurs as a result of a decrease in the elasticity and ability of the lung tissue to expand during inspiration.
Comparative lung percussion is successfully used to diagnose pathological processes in any part of these organs. In this case, the percussion tone is compared with normal in symmetrical areas. In healthy people, it is the same in the right and left half of the chest.
Thus, lung percussion, carried out in combination with other basic methods of clinical examination of the patient, allows you to quickly identify changes in the lung tissue and make a preliminary diagnosis of the disease.