Материал: General propedeutics of internal diseases_Nemtsov-LM_2016

the underlying organs. The organs or tissues lying beneath the percussing area begin vibrating and these vibrations are transmitted to the surrounding air whose vibration is perceived by our ears as sounds. Liquids and airless tissues give dull sounds which can be heard with difficulty, such as the sound of a percussed femur (femoral sound). Airless organs and also liquids cannot therefore be differentiated by percussion. The properties of each particular sound obtained by percussion of the chest or the abdomen, and differing from the femoral sound, depend on the amount of air or gas enclosed within the chest or abdomen. The difference in the sounds of percussed lungs, liver, spleen, heart, stomach and other organs depends on (a) the different amount of gas or air inside or round the percussed organ; (b) tension of the tissue; and (c) different strength of the percussion stroke transmitted to this gas or air.

Mediate percussion is done by tapping with a plexor (hammer) on a pleximeter placed on the body, or by a finger on another finger. In immediate percussion the examined part of the body is struck directly by the soft tip of the index finger. To make tapping stronger, the index finger may be first held by the side of the middle finger and then released. This method was proposed by Obraztsov. Its advantage is that the striking finger feels the resistance of the examined part of the body.

Percussion is done with a slightly flexed middle finger on the dorsal side of the second phalanx of the middle finger of the opposite hand, which is pressed tightly against the examined part of the body. Percussion should be done by the movement of the wrist alone without involving the forearm into the movement. Striking intensity should be uniform, blows must be quick and short, directed perpendicularly to the intervening finger. Tapping should not be strong.

Sounds obtained by percussion differ in strength (clearness), pitch, and tone. Sounds may be strong and clear (resonant) or soft and dull; they may be high or low, and either tympanic or non-tympanic (and with metallic tinkling).

Resonance (clearness, loudness, sound volume) of the percussion sound largely depends on the vibration amplitude: the stronger the tapping the louder is the sound; uniform strength of tapping is therefore required. A louder sound will be heard during percussion of an organ containing greater amount of air. In healthy persons resonant and clear sounds are heard in percussion of thoracic and abdominal organs filled with gas or air (lungs, stomach, and intestine).

Soft or dull sound is heard during percussion of the chest and the abdominal wall overlying airless organs (liver, heart, spleen), and also during percussion of muscles (femoral sound). Resonant and clear sound will become soft if the amount of air decreases inside the lung or if liquid is accumulated between the lungs and the chest wall (in the pleural cavity).

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The pitch of the sound depends on the vibration frequency: the smaller the volume of the examined organ, the higher the vibration frequency, hence the higher the pitch. Percussion of healthy lungs in children gives higher sounds than in adults. The sound of a lung containing excess air (emphysema) is lower than that of a healthy lung. This sound is called bandbox (box sound). Normal vibration frequency of a healthy lung during percussion is 109-130 per second, while in emphysema the frequency decreases to 70-80 c/s. Quite the opposite, if the pulmonary tissue becomes more consolidated, the frequency increases to 400 c/s and more.

Tympanic sound resembles the sound of a drum (hence its name: Gk tympanon drum). Tympany differs from a non-tympanic sound by higher regularity of vibrations and therefore it approaches a musical tone, while a non-tympanic sound includes many aperiodic vibrations and sounds like noise. A tympanic sound appears when the tension in the wall of an aircontaining organ decreases. Tympany can be heard during percussion of the stomach and the intestine of healthy people. Tympany is absent during percussion of healthy lungs, but if the tension in the pulmonary tissue decreases, tympanic sounds can be heard. This occurs in incomplete compression of the lung by the pleural effusion, in inflammation or edema of the lung (the percussion sound then becomes dull tympanic). A tympanic sound can also be heard if air cavities are formed in the lungs or when air penetrates the pleural cavity. Tympany is heard over large caverns and in open pneumothorax (the sound is resonant). Since air filled organs produce resonant percussion sounds and airless organs give dull sounds, the difference between these sounds helps locate the borders between these organs (e.g. between the lungs and the liver, the lungs and the heart, etc.).

Topographic percussion is used to determine the borders, size and shape of organs. Comparison of sounds on symmetrical points of the chest is called comparative percussion.

Tapping strength can vary depending on the purpose of the examination.

Loud percussion (with a normal force of tapping), light (quite), and lightest (quitest, threshold) percussion are differentiated. The heavier the percussion stroke, the greater is the area and depth to which the tissues are set vibrating, and hence the more resonant is the sound. In heavy or deep percussion, tissues lying at a distance of 4- 7 cm from the pleximeter are involved. In light or surface percussion the examined zone has the radius of 2—4 cm. Loud percussion should therefore be used to examine deeply located organs, and light percussion - for examining superficial organs. Light percussion is used to determine the size and borders of various organs (liver, lungs and heart).

Main rules of percussion.

1. The patient should be in a comfortable posture and relaxed. The best position is standing or sitting. Patients with grave diseases should be

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percussed in the lying position. When the patient is percussed from his back, he should be sitting on a chair, his face turned to the chair back. The head should be slightly bent forward; his arms should rest against his lap. In this position muscle relaxation is the greatest and percussion thus becomes more easy.

2.The room should be warm and protected from external noise.

3.The physician should be in a comfortable position as well.

4.A pleximeter or the middle finger of the left hand, which is normally used in the finger-to-finger percussion, should be pressed tightly to the examined surface. The neighbouring fingers should be somewhat set apart and tightly pressed to the patient's body. This is necessary to delimit propagation of vibrations arising during percussion. The physician's hands should be warm.

5.The percussion sound should be produced by the tapping movement of the hand alone. The sound should be short and distinct. Tapping should be uniform, the force of percussion strokes depending on the object being examined (see above).

6.In topographic percussion, the finger-pleximeter should be placed parallel to the anticipated border of the organ. Organs giving resonant note should be examined first: the ear will better detect changes in sound intensity. The border is marked by the edge of the pleximeter directed toward the zone of the more resonant sounds.

7.Comparative percussion should be carried out on exactly symmetrical parts of the body.

Percussion of lungs

Depending on the object of examination, various methods of percussion are used to examine the lungs. The examination begins with comparative percussion.

Comparative percussion of lungs

Comparative percussion is performed to a comparison of the percussion sound (resonance) on the symmetrical points of the appropriate topographical lines of the chest (Table 1).

The certain sequence is followed in comparative percussion. Percussion sounds over the lung apices (in the front) on the symmetrical points of the chest are first compared; the pleximeter finger is placed parallel to the clavicle. The plexor finger is then used to strike the clavicle which is used as a pleximeter in this case. During percussion of the lungs below the clavicle, the pleximeter finger is placed in the interspace at the strictly symmetrical points of the left and right sides of the chest.

The percussion sounds are compared only to the level of the 3th rib along the parasternalis line and to the level of 4th rib along the

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medioclavicular line (further the percussion is continued only on the right side of the chest to hepatic dullness). The heart lying below this level changes the percussion sound. For comparative percussion of the axillary region, the patient should raise his arms and clamp the hands at the back of the head. Comparative percussion of the lungs on the back begins with suprascapular areas. The pleximeter finger is placed horizontally, while during percussion of the regions between the scapulae, the pleximeter should be vertical. The patient should cross his arms on the chest to displace the scapulae anteriorly (away from the backbone). During percussion of the points lying below the scapulae, the pleximeter should again be horizontal; in the interspace it should be placed parallel to the ribs.

Percussion sounds of the lungs of a healthy person cannot be of equal strength, length or pitch even if the percussion blows are uniform at symmetrical points. This depends on the mass and thickness of the pulmonary layer and also on the influence of the adjacent organs on the percussion sound. It is softer and shorter (1) over the right upper lobe because it is located somewhat below the left (due to the shorter right upper bronchus) and also because of the better development of the muscles of the appropriate

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side of the shoulder girdle; (2) in the second and third interspace on the left, because of the closer location of the heart; (3) over the upper lobes of the lung (compared with the lower lobes) because of the varying thickness of pneumatic pulmonary tissue; (4) in the right axillary region (compared with the left one) because of the closer location of the liver. The difference in percussion sounds here depends on the fact that the diaphragm and the lung border on the left with the stomach whose bottom is filled with air and gives a loud tympanic sound during percussion (Traube's semilunar space). The percussion sound in the left axillary region is therefore louder and higher (with tympanic character) because of the resonant effect (“air bladder”) of the stomach.

The percussion sound can change in pathological processes because of the decreased content or full absence of air in a part of the lung, and because of the pleural fluid (transudate, effusion, blood), increased airiness of the lung tissue, and the presence of air in the pleural cavity (pneumothorax).

The amount of air in the lungs decreases in (1) pneumosclerosis, fibrous-focal tuberculosis, (2) pleural adhesion or obliteration of the pleural cavity which interferes with normal distention of the lung during inspiration; the difference in the percussion sound will be more pronounced at the inspiration level and weaker during the expiration; (3) lobular and especially confluent pneumonia, in which pulmonary tissue alternates with consolidations; (4) considerable edema of the lungs, especially in the inferiolateral regions due to insufficient contractility of the left ventricle; (5) compression of the pulmonary tissue by the pleural fluid (compression atelectasis) above the fluid level; (6) complete obstruction of the large bronchus with a tumour and gradual resorption of air from the lungs below the closure of the lumen (obstructive atelectasis). Clear pulmonary sounds become shorter and higher (i.e. duller) in the mentioned pathological conditions. If these conditions are attended by decreased tension in the elastic elements of the pulmonary tissue, e.g. in the presence of compression or obstructive atelectasis, the sound over the atelectatic zone becomes dull with a tympanic tone. This sound can also be heard during percussion of a patient with acute lobar pneumonia at its first stage, when the alveoli of the affected lobe, in addition to air, contain also a small amount of fluid.

A complete absence of air in the entire lobe of the lung or its part (segment) is observed in the following cases: (a) acute lobar pneumonia at the consolidation stage, when the alveoli are filled with the inflammatory exudate containing fibrin; (b) formation in the lung of a large cavity, which is filled with the inflammatory fluid (sputum, pus, echinococcous cysts, etc.), or heterogeneous airless tissue (tumour); (c) accumulation of fluid in the pleural cavity (transudate, exudate, blood). Percussion over airless parts of the lung or over fluid accumulated in the pleural cavity gives a soft short and high sound which is called dull or, by analogy with the percussion sounds of

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