Percussion

PERCUSSION, one of the most important methods for examining internal organs. Percussion consists of the fact that when tapping the area being examined, a sound is produced, based on the properties of which conclusions are drawn about the condition of the organ located under the percussed area. History. The method of percussion was proposed by the Viennese physician Auenbrugger (Joseph Leopold Auenbrugger), who in 1761 published a booklet "Inventum novum ex percussione thoracis humani ut signo abstrusos interni pectoris morbos detegendi" (Vindobana). This method did not become widespread until 1808, when Corvisart published it in French, accompanied by a number of observations from his own practice. The further development and consolidation of the method in medical practice followed as a result of a large number of works. Among the authors of these works, it is necessary to mention Piorry - the inventor of the plessimeter, Barry - the inventor of the percussion hammer, Skoda, Traube, Wintrich. The modern theory of percussion was created by the works of A. and R. Geigel, Th. Selling, and Edelmaim, who developed on the basis of modern physiological knowledge the question of the percussive sound. Theory of percussion. For a correct understanding of percussive sound phenomena, it must be remembered that all sound phenomena represent the movement of sound waves. The simplest form of sound wave movement, perceptible to the ear, is formed by tones. They are caused by periodic regular vibrations of a sounding body. But sounding bodies can produce not only a simple tone, but also a mixture of tones, where together with the main tone there are more or less numerous partial tones, or overtones. The emergence of overtones can be easily imagined from the following example: a string of a certain length can vibrate in such a way that nodes of vibration are formed only at its ends. In this case, it gives a simple tone. But in addition, a node of vibration can also form in the middle of the string, and then an octave of the main tone is obtained. Three or four nodes of vibration can form with the appearance of corresponding partial tones, or overtones. In reality, each string gives, in addition to the main tone, more or less multi-tonal overtones. Our hearing has the property of perceiving such a mixture of tones, which we call ringing, as something unified, without paying attention to the overtones. Only with a certain skill and attention is it possible to perceive overtones separately. When there are very high overtones, far removed from the main tone, their distinction becomes easy. They have a characteristic metallic character and are often observed during percussion and auscultation. In addition to ringing, there is another mixture of tones - noise. It represents a fundamentally different composition of tones. The constituent parts of ringing either do not change or change insignificantly during their sounding in height and strength, and the number of vibrations of the individual constituent parts of ringing stands in direct relation to the number of vibrations of the main tone. With noise, the number, strength, height, and duration of the constituent parts of the tone mixture change quickly and non-periodically. With a graphical recording of ringing, a regular periodic curve is obtained, and with a recording of noise - an irregular aperiodic curve. The sound obtained during percussion approaches in its character either to ringing or to noise. In the stomach and intestines, air or gas that has been set into vibration entirely under the influence of a percussive blow provides conditions for the occurrence of periodic vibrations with the dominance of the main tone. It is tympanic, resembling the sound of a drum. Air in a normally tense lung gives interrupted vibrations, and here overtones predominate, the main tone recedes into the background, and a sound with characteristic properties of noise is obtained. Conversely, in a completely relaxed lung that is vibrating during percussion, there are conditions for the occurrence of a dominant main tone, and the percussive sound begins to resemble the percussive sound of the stomach or intestines, becoming tympanic. With increased tension of gases in the intestines, vibrations from the percussive blow become interrupted. The sound loses its musicality and becomes similar to the sound during percussion of the lung - it becomes noise. With very strong tension of gas in cavities, for example in many cases of pneumothorax, the overtones are especially high, due to which a metallic tint of the percussive sound is obtained. This emergence of continuous and interrupted vibrations has special significance for the analysis of the percussive sound. A non-tense lung sounds throughout, while a tense one sounds in separate places. Hence the exceptional importance of percussion of the lung, because in a normally tense lung, depending on the strength of the primary impact of the percussive blow, larger or smaller areas are set into vibration, and therefore it is possible to get an idea of the volume and boundaries of the percussed part. To the question of what sounds during percussion, A. Geigel answers in his works, proving that the body giving the sound is the entire collection of lung tissues at the percussed place. The chest cage as a sounding body does not have great significance. Basically, the chest wall conducts the shaking waves of the sound impact to the sounding body and conducts back from the sounding body the sound vibrations caused by these shaking waves. Part of the energy of the impact is converted into heat along the path through the chest wall and is lost for causing sound, and the thicker the chest wall, the greater this loss. Weakening and shortening of sound phenomena, i.e., decrease in amplitude and more rapid attenuation of sound waves, are combined in the general concept of dullness. Depending on the purpose, two fundamentally different types of percussion can be distinguished. Percussion can aim to: compare anatomically identical areas and delimit anatomically different areas. In the first case, it is necessary during percussion to set large areas into vibration as a whole, in the second case it is necessary to set as small areas as possible into vibration. In the first case, continuous vibrations are caused, in the second - interrupted vibrations. Therefore, it is obvious that the method in comparative percussion must be different than in delimiting percussion. In comparative percussion - a large surface of impact, a prolonged impact, in delimiting percussion - a small surface of impact, a short impact. The possibility of such different adaptation of the percussive impact for these different purposes exists only with indirect percussion and explains its superiority over direct percussion. The bones of the percussing finger, the plate of the plessimeter are much harder than the chest wall, the percussing finger or hammer retreats back more quickly, the time of impact becomes shorter. By pressing the plessimeter more strongly, one can change the tension of the underlying parts of the chest wall. With increasing tension, there is an increasing tendency for local limitation of the impact, an increasing inclination of the body to give interrupted vibrations. With the limitation of the local action of the impact and the consequent increase in the development of interrupted vibrations, it becomes possible to determine the boundaries. Methods and technique of percussion. Due to all that has just been said, direct percussion is almost never used. Of the indirect methods, the following are usually used: 1) Percussion of the finger on the finger, 2) Percussion of the finger on the plessimeter and 3) Percussion of the hammer on the plessimeter. Of these methods, the most technically difficult to master is percussion of the finger on the finger, but in practice it gives in a number of cases more accurate results than percussion on the plessimeter, because it combines with the auditory sensation the sensation of resistance during the percussive impact; the point is that where percussion gives dullness, there is also an increase in resistance during percussion. The technical execution of percussion requires great attention, and mastery of it can be obtained only as a result of systematic exercises. A small difference in the curvature of the chest, in the height of the shoulders, in the development of musculature, a slight curvature of the spine can lead to a clear difference in sound, and without paying attention to the mentioned deviations from the normal structure of the body, this difference in sound can be interpreted as a lung disease. In comparative percussion, it is necessary to be at the same distance from the percussed places, since the strength of sound changes in proportion to the square of the distance. In general, it is necessary to pay great attention to the uniformity of conditions: equal strength of the percussive impact, equal position, equal pressure of the finger on which percussion is performed. In percussion of the finger on the finger, the part of the finger serving as a plessimeter must lie completely against the chest wall in order to transmit the percussive impact over a wide area. The strength of the impact depends partly on the thickness of the soft parts of the chest wall, partly on the intention of the examiner to achieve a more or less deep action. Small superficial foci with weak percussion still give a difference in sound, while they are not revealed at all with stronger percussion. In all doubtful dullnesses, it is necessary to consequently try weak, moderate, and strong percussion.

The percussion stroke should be performed only with the movement of one hand and should not be too short. It is necessary to pay close attention to percussing from both sides or along the intercostal spaces or along the ribs, and moreover, at the same phase of respiration. In restrictive percussion, based on the doctrine of continuous and interrupted vibrations, the fundamental condition is a short stroke, a small striking surface. The percussion stroke is therefore light, short, the plessimeter stands on its edge, and the percussing finger touches the chest only with its tip. Delimiting percussion has as its task to delimit areas of different sound, usually more air-containing from less air-containing or airless ones. Experience shows that the difference in sound is best revealed when percussing from air-containing parts to less air-filled and airless ones. It is important above all not to finish percussion too early, but to be advisable to first cross the boundary, then go back and repeat this until the boundary appears definitely. Besides these usual methods in medical practice of delimiting percussion, the exceptionally great importance in clinical practice for determining the normal boundaries of organs and delimiting pathological changes constantly prompted researchers to seek new methods. Of all the proposed methods, the following deserve mention: the Goldscheider method (quiet percussion with a percussive sound at the lower limit of perception), the Goldscheider method-orthopercussion, the tactile percussion of Ebstein, and auscultatory percussion. The Goldscheider method of percussion at the boundary of perception of the percussive sound is based on the universally accepted position that in delimiting percussion the percussion stroke should be light and short, and the resulting sound should be quiet. This circumstance - the quiet percussive sound - has been put forward by Goldscheider as the most important requirement in delimiting percussion. Proceeding from the position that it is easier to distinguish small from nothing than larger from smaller, he proposes in delimiting percussion to percuss so quietly that when percussing airless parts nothing is heard. The evaluation of this method in the literature is varied, but one must join the opinion of Sahli that even with somewhat stronger percussion, when properly performed, the same results are obtained. Orthopercussion according to Goldscheider consists in determining the deep cardiac dullness by percussing not perpendicular to the surface of the body, but perpendicular to the frontal surface of the heart, i.e., percussing sagittally. According to Goldscheider, the sagittal sound rays sent at this time pass through the chest wall, and thanks to this it is possible to project the true size of the heart onto the anterior surface of the chest regardless of its curvature, as is possible in orthodiagraphy by the Moritz method. According to the research of Sahli, with the help of orthopercussion approximately correct results are obtained as long as the percussed surface of the chest is approximately frontal, which is usually the case in percussion of the heart, normal or moderately enlarged. In other words, this method also does not give any advantages over the usual method of percussion. Tactile percussion of Ebstein consists in using only touch in percussion. It is performed either directly with the terminal phalanges of the fingers or by tapping on the finger or on the plessimeter, "shortly and gently," "more like palpating and probing in depth." In this case, instead of a percussive stroke, something like a percussive thrust should be obtained, which does not cause any sound phenomenon. According to Edens, with this method it is undoubtedly possible to determine the boundaries of organs, but the usual methods of delimiting percussion are more productive than tactile percussion according to Ebstein. Auscultatory percussion, used by Laennec to determine the size of cavities and pneumothorax, was first recommended for determining the boundaries of organs (see Auscultation). Quality of the percussive sound. When percussing different places on the surface of the body, a percussive sound of different quality is obtained. Based on the research of Zelling, Edens, and Ewald, the following properties of the percussive sound can be considered firmly established: loud and quiet, long and short, low and high, tympanic and non-tympanic. An example of a loud sound is the sound obtained when percussing normal lungs; an example of a quiet sound is the sound obtained when percussing a large mass of muscle, e.g., the thigh (femoral sound). Experience shows that a loud sound corresponds to organs containing air, and a quiet sound to airless organs, regardless of whether they are compact or filled with fluid. Thanks to this, first, there is the possibility of delimiting organs of different anatomical structure, and second, an increase or decrease in the air content in organs can influence the change in sound. The less the air content in the percussed organ under equal conditions, the quieter the sound in general, and vice versa. In addition, the occurrence of a more or less loud sound is also determined by the depth of the air-containing organ in the direction of the percussion stroke: the thicker the air-containing layer, the louder the sound. With an increase in the air content in the lungs, e.g., in emphysema, an abnormally loud and low sound is obtained, called boxy or pillow-like, i.e., resembling the sound when percussing a box or pillow. The expression "clear" is often used synonymously with "loud," and "dull" with "quiet." Between loud and quiet sounds there exist innumerable transitional forms. A sound that is not quite loud and not quite quiet is called dull. Dulling of the percussive sound is explained by the presence of resistance that muffles the sound vibrations. Since all resistances that interrupt sound vibrations simultaneously must reduce the amplitude of the vibration, it can be said that as a result of each dulling the sound becomes shorter and higher. Clinical observations coincide with these physical data. In practice one speaks of dulling, e.g., of the lung apex, when the sound has only become quieter, or only shorter, or only higher, but it may also show at the same time two or all three of the mentioned changes. Besides these differences depending on the amplitude of the sound wave, it is necessary to take into account changes depending on the difference in the form of vibration and in the number of vibrations. This above all refers to the distinction between tympanic and non-tympanic loud sounds. An example of the first is the sound over the air- and gas-filled abdominal viscera, and an example of the second is the lung sound. In the physical sense, tympanic and non-tympanic loud percussive sounds are noises, but in the tympanic percussive sound the vibrations are so periodic that the ear can recognize the number of vibrations in relation to other tones or the height of its pitch. It should be noted that there is no definite sharp difference between tympanic and non-tympanic loud sounds. The non-tympanic sound of an air-containing organ, as has already been indicated above, passes into a tympanic sound or back again when the tension under which the air or the wall of the air space is located decreases or increases. An essential characteristic of the tympanic sound is the possibility of relatively clearly distinguishing a certain pitch. From this, low tympanic and high tympanic sounds are distinguished. Since the height of the percussive sound depends on the tension of the membrane enclosing the air space and on the size of the air space, and a decrease in the size of the air space not only affects the height of the percussive sound but also makes it quieter, the combination often observed in clinics of a dull tympanic sound can frequently result. Besides the described qualities of the percussive sound, two more are observed in percussion: the so-called metallic sound and the crack-of-the-pot sound (bruit de pot fele) or coin sound. The metallic character of the percussive sound consists in its peculiarly high tone, only descriptively called a metallic resonance, perceived either throughout the entire sensation of the sound or only at its end. In the latter case one speaks of a metallic resonance. It can be most easily imagined if one percusses a moderately inflated cheek, preferably with a hammer on a plessimeter. The metallic sound was first described by Laennec. The correct explanation now universally accepted for the metallic sound was given by A. Haegel, who sees its cause in the predominance of high overtones. It is most often observed in the accumulation of air in the pleural space, in pneumopericardium, in cavities, and according to Wintrich the cavity should have a diameter of at least 6 cm in the smallest transverse dimension. Only as an exception is the metallic sound obtained in smaller cavities. In such cases it is always a matter of cavities with smooth walls and with considerable tension of their walls. The metallic sound becomes particularly clear when percussing with a stick on a plessimeter according to Heubner. Its appearance is explained by the fact that where interrupted vibrations predominate, the fundamental tone recedes, and the overtones can sharply come forward.

The occurrence of interrupted vibrations is favored by a rapid blow, a small striking surface, and the elasticity of the body being struck. Therefore, it becomes clear why the wall of a cavity must be tense and why a percussion stick and plessimeter are used for percussion. Over small cavities, a metallic sound is not heard, because, according to R. Geigel, with small cavities that produce a high fundamental tone, the height of distant metallic overtones exceeds the limit of our hearing. Cavities must have smooth walls, because in this case, due to interference, fine-walled standing sound waves can form, which produce high and non-harmonic overtones, causing the metallic character of the sound. The metallic sound arises mainly due to the vibration of air and to a lesser extent due to the vibration of the tense wall. Therefore, the thinner the wall of the corresponding cavity, the more easily the metallic sound is perceived. The relationship of the metallic sound to the tympanic and non-tympanic sound is, according to R. Geigel, as follows: continuous vibrations-tympanic sound, interrupted vibrations-non-tympanic sound, a higher degree of interrupted vibrations-metallic sound. The sound of a cracked pot, or coin sound, was also first described by Laennec. It is a rattling percussion sound, similar to that obtained when tapping a cracked pot or shaking coins held between two palms. It can occur during percussion of the chest wall and under completely physiological conditions. It can be heard during percussion of a crying child or in an adult with a thin, pliable chest wall during speech and during forced expiration with the vocal cords semi-opened. The conditions for its occurrence are more favorable the closer the trachea and the stronger the percussion. It is particularly clear with the mouth open. It is then observed over relaxed or partially indurated lung tissue. Thus, the sound of a cracked pot appears at the border of pleural exudate and over infiltrates. However, under these conditions, it is a rare phenomenon. The sound of a cracked pot has certain diagnostic value for the diagnosis of pulmonary cavities. With superficially located cavities of several cm³ in volume, communicating with bronchi, the sound of a cracked pot is often observed with stronger percussion. It apparently arises because under the influence of suddenly arising pressure (percussion blow), a certain amount of air exits in spurts with a hissing sound through a narrow opening (bronchus).-The sound phenomena observed during percussion of the lungs can change their pitch depending on a number of accompanying phenomena. These phenomena are particularly often observed over cavities. These are: Vintrich's change of sound (see), in which the percussion sound with the mouth open becomes higher, and with the mouth closed-lower; Williams' tracheal tone; Bürmer's change of sound; and Gerhardt's change of sound (see). Percussion of the lungs. Percussion and all changes in the percussion sound have the greatest significance in the physical examination of the lungs, where both types of percussion are used, comparative and delimiting. When determining the boundaries of the lungs, one starts from the right anterior lower boundary, percussing from top to bottom. Already from the IV rib, the sound becomes shorter, higher, and quieter, because from here, due to the dome-shaped bulging upward of the liver, the layer giving sound of lung tissue is diminished. The elevation, shortening, and attenuation of the lung sound reach a maximum at the VI rib and indicate that the lower edge of the lung has been reached. The boundaries of the lungs (see Lungs-anatomy) are at the VIII rib according to other reference lines. The position of the boundaries changes with deep inspiration and expiration, which is why the boundary is always determined at restful breathing (see Lungs-anatomy). Some inspiratory clarification of the sound at the lower edge of the lungs can also occur when the lung is completely adhered, and it does not indicate a lowering of the boundaries, but an increase in the airiness of the lung edge. Determining the boundaries of the lung apices encounters certain difficulties, depending on the anatomical features of this area. The lung apex dome-shaped rises above the clavicle and is covered by soft parts which themselves to a certain degree participate in the formation of the dome. Here there are no sharp boundaries anywhere, as at the base of the lungs; therefore, the boundaries of the apices are less sharp and precise. The lung sound over the apices extends in the form of a band, widening forward and backward. Its narrowest point is on the anterior edge of m. cucullaris and is called the space of Krenig (Kronig). The percussion determination of the width of this space, which normally is at least 6 cm and the same on both sides, is of great importance for determining initial tuberculous changes in the lung apices. For determining difficult-to-access boundaries between both bellies of the sternocleidomastoid muscle, a special plessimeter is recommended. Percussion should be light and perpendicular to the boundary. The method of percussion of the apices according to Goldscheider has not found much practical application due to the difficulty of the technique. The boundaries of the lungs can expand and narrow under pathological conditions. Increase occurs mainly in emphysema, both general and vicarious. With incomplete obstruction of a bronchus by a foreign body, the resistance for the backward exit of air increases, and the corresponding lung lobe expands. A higher position of the lower lung boundaries is most often the result of all those changes that cause an increase in intra-abdominal pressure: meteorism, ascites, significant tumors of the abdominal cavity. In this case, due to the decrease in negative intrathoracic pressure, the lung not only moves upward but is retracted concentrically in all directions from front to back and toward the hilum to such an extent that the heart is more exposed. Enlargement of the heart, especially a fluid-filled pericard, can not only push the lungs apart and increase the superficial cardiac dullness, but also cause an upward displacement of the lower lung boundary due to the decrease in negative intrathoracic pressure. Finally, all those processes that cause shrinking of the lungs also cause narrowing of the lung boundaries. The percussion sound undergoes many qualitative changes over the lungs, because it is natural that any change in the structure of the lungs has a significant influence on the characteristics of the lung sound. The lung sound can be abnormally loud and low, tympanic, or finally more or less dull or completely dull. All these changes are most easily determined by comparing with each other symmetrical or neighboring, normally equally sounding areas. Therefore, comparative percussion has extremely great importance in the examination of the lungs. In order not to overlook more subtle changes in the percussion sound, it is necessary to make it a rule to perform comparative percussion sequentially with varying force. On the other hand, a slight difference in sound should be taken into account only with great caution. One must bear in mind that even in healthy individuals, the sound over both apices is rarely completely identical, because one shoulder or apex may be lower than the other, or one clavicle higher than the other, or the musculature of one shoulder thicker than the other. The sound over the lower lobe on the right side is often somewhat higher and shorter than on the left due to the proximity of the large mass of the liver. This is particularly noticeable in children with their relatively large liver and often occurring meteorism. When changing position from sitting to standing, these sound changes disappear. Over the left lower lobe, the sound is often tympanic due to the admixture of the sound of the gastric air bubble, which lies adjacent to the lung here. The sound is generally dull when a smaller amount of air-containing lung tissue falls within the sphere of action of the percussion blow. Conditions for the occurrence of such conditions arise: 1) when an airless mass is interposed between the lungs and the chest wall (exudate, adhesions, tumors), 2) when there is airlessness or decreased airiness of the lung parenchyma. The latter circumstance can occur in complete or partial atelectasis or collapse of alveoli due to compressions or bronchial obstruction with subsequent absorption of air in the communicating lung tissue, in complete or partial filling of alveoli with airless inflammatory exudate (pneumonia), or in more or less complete replacement of lung tissue by newly formed tumor tissue. The result of percussion varies depending on whether these changes form large, surface-extending foci, or small foci which partly reach the surface, partly are separated from the chest wall by air-containing lung tissue, or finally large foci lying in depth. Therefore, since it is not known in advance what is the cause of the dullness, it is useful to apply percussion of varying force sequentially. From the different results obtained sequentially, one can draw a conclusion about the nature of the cause that caused the dullness and determine whether the dullness is superficial or deep.

Experience teaches that isolated foci of consolidation, even when superficially located, must have at least several square centimeters of surface area and lie no deeper than 6-8 cm from the surface to produce dullness. When deeply situated, they must be considerably larger. Multiple foci, even small ones if densely arranged, can cause a reduction in clear sound. Conversely, in other cases, even very densely arranged small foci of consolidation may not produce dullness at all. This depends not only on the presence of a large amount of air-containing tissue, but also on the relaxation of this tissue, leading to increased resonance of the percussion sound, and also on phenomena of compensatory emphysema. The sound over effusion shows the greatest changes. It is very short and quiet, poorest in low tones, completely non-resonant, and is accompanied by a strong sensation of resistance. The sound over a completely infiltrated and exudate-filled lung is never as short and quiet, but is usually somewhat resonant and gives less sensation of resistance. Over adhesions, increased sensation of resistance is often observed first. The sound is usually less short and quiet, and also less poor in low tones than the sound over effusions and pneumonic foci. The location of fluid in effusions is very characteristic and gives a typical, important boundary for differential diagnosis, named after the authors who first described it, the Ellis-Damoiseau line (see Pleurisy). In pneumothorax, in most cases the percussion sound is abnormally loud and non-tympanic. A tympanic sound over pneumothorax is observed only in rare cases. This is because in the overwhelming majority of cases there is so-called valve pneumothorax, in which the air is under considerable pressure. The loud and low sound of pneumothorax is often revealed only with more careful percussion and attracts attention mainly by the fact that it sharply transitions beyond the normal boundaries of the lungs. In right-sided pneumothorax, the loud sound reduces the liver dullness from above and the cardiac dullness on the right. In left-sided pneumothorax, the splenic dullness disappears and the cardiac dullness decreases or even disappears. Additionally, there are usually signs of displacement of organs adjacent to the pneumothorax. As a very characteristic phenomenon to all these symptoms is added a metallic timbre to the sound, sometimes audible already with ordinary percussion and appearing especially distinctly when percussing with a stick over a plessimeter. In sero- and pyopneumothorax, the physical phenomena are the same, and pneumothorax with fluid accumulation presents the same symptoms as pure pneumothorax. Due to the increased loudness of the sound and the low position of the boundaries in pneumothorax, the dullness from fluid in the pleural cavity is often overlooked. Among the symptoms characteristic of fluid in pneumothorax, it is necessary to point out the extremely easy mobility of the dullness it produces when changing position. Then the height of the percussion sound in the upright position is lower, in the recumbent position higher, or vice versa—Biemer's change in sound. Percussion of the heart. The anatomotopographic position of the heart, surrounded on the right, above, and left by the lungs, and below by the liver, and directly adjacent only in a small part to the chest wall, determines the great importance of its examination by percussion in general and of special methods in particular. It is quite understandable that only restrictive percussion can be used to determine the boundaries of the heart and only for determining the right, upper, and left boundaries, since below the cardiac dullness merges with the liver dullness and percussion naturally cannot be delimited. The fact that the heart is directly adjacent to the chest wall only in a small part, and in its larger part is covered by the lungs, is reflected in the percussion sound, which at the point where the heart adjoins the chest wall gives a completely dull sound—the absolute dullness of the heart, while in the areas covered by the lungs gives dullness—the relative dullness of the heart. When considering these relationships from the point of view of the factor determining them, the absolute dullness of the heart is also called the superficial dullness of the heart, and the relative dullness—the deep dullness of the heart. It is clear that absolute cardiac dullness is much easier to determine by percussion and therefore it was exclusively used for a long time in determining the size of the heart. With enlargement of the heart or accumulation of fluid in the pericardium, the lung edges are pushed aside in both directions, and as a result, the superficial dullness of the heart increases. Therefore, often the size of the superficial dullness can be used to judge the size of the heart or the presence of fluid in the pericardium. It is clear that this can be done only with certain reservations. Thus, in emphysema or where the lung edge is fixed by pleural adhesions around the heart, the superficial cardiac dullness increases or decreases, although the size of the heart remains normal, because in essence when determining absolute cardiac dullness, the boundaries of the lungs are determined, not the boundaries of the heart. In more recent times, increasing importance is attached to determining the relative dullness of the heart, all the more so since the possibility of determining it with sufficient accuracy has been proven. Clinical experience teaches that one should never determine only the superficial dullness in cardiac diagnosis; it is always necessary to simultaneously determine the deep dullness as well. The relative dullness is located around the absolute one. Its right border is formed by the right atrium, the upper border by the right atrium and right ventricle, the left border by the left ventricle. Comparison with orthodiagraphic data shows that the boundary of the relative dullness of the heart should be considered the line where, with percussion towards the heart, the first significant changes in sound appear. Since the time of Laennec, who first recommended determining absolute dullness with weak percussion and relative dullness only with strong percussion, most researchers have adhered to this technique in cardiac percussion. But recently, indications have appeared that the relative dullness of the heart is determined equally or even better with weak percussion (Toldschneider and others). Thanks to the research of these authors and orthodiagraphic control, there can be no doubt that weak percussion determines the relative dullness of the heart more easily and accurately than strong percussion. In establishing the technique for determining the relative dullness of the heart, one proceeds from the position that the heart lies on the liver and its extreme points must be at the boundary of the lungs and liver. Therefore, one can begin to determine the boundaries of the heart only after the boundary of the lungs has been determined on the right and in front. Percussion is started from the right midclavicular line, and, observing all the rules of restrictive percussion technique, percussion is done towards the midline, going just above the boundary of the lungs. The rightmost point of cardiac dullness is determined at the right edge of the sternum or 1/2-1 cm short of it. From this rightmost point, the right border of the heart goes upward in the form of a steep arc and, at the lower edge of the left third costal cartilage, at its attachment to the sternum, reaches the highest point of cardiac dullness—the upper border of the heart. From here, the border of the heart again in an arc, but a flatter one, extends leftward downward, takes a vertical direction inward from the nipple line, and ends near the point where the apical impulse of the heart is felt. When determining the left border of the heart, one must always take into account the circumstance that the location of the left border is naturally determined by the location of the cardiac impulse. The left border is therefore always determined by percussing towards the cardiac impulse, and it is necessary to percuss not along a line going perpendicular to the impulse, but in the intercostal spaces, because transitions in the percussion sound, lower in the intercostal spaces and higher on the ribs, can lead to erroneous determination of the boundaries. In the absence of a cardiac impulse, percussion is done in the fifth left intercostal space. A certain difficulty in evaluating cardiac percussion when assigning its boundaries to reference lines of the body is presented by the significant variations in the size of the chest in different subjects, and therefore when assigning the boundaries of the heart only to reference lines of the body, especially the left border of relative dullness only to the nipple line, one can come to incorrect conclusions. Therefore, it is very appropriate to take into account the absolute size of the deep cardiac dullness. The greatest extent of relative dullness is measured from the midline and gives 2.5-3.5 cm to the right and 6.5-8.5 cm to the left. The total width of dullness is therefore 9-13 cm. These values of cardiac dullness are only average values, which in each individual case allow for a correct conclusion only when taking into account a number of factors: age, sex, height, weight, muscular development, and especially the ratio of chest dimensions—length, width, curvature, height of diaphragm position. In children, the upper border lies higher and the left border more outward, since first, the child's heart is relatively larger, and second, the diaphragm in children is higher.

It is then necessary to take into account that the boundaries of the heart can change during respiration and when the position of the subject changes. Therefore, the heart boundaries given above, as is generally accepted, are given with calm respiration and with the subject in the supine position. During deep inspiration, the superficial dullness of the heart decreases more or less significantly and may even completely disappear. On the contrary, during deep expiration, the superficial dullness of the heart increases and can sometimes extend to the right edge of the sternum. The deep dullness of the heart during inspiration is usually narrower, and its left border descends more steeply. During strong expiration, as research by Moritz and Dietlen shows, the right border maintains its position, while the left border moves upward and outward. When lying on the left side, there is an increase to the left of both deep and superficial cardiac dullness. When lying on the right side, there is a shift in the opposite order, and to the right of the sternum, not only a significant increase in deep dullness can be detected, but sometimes the appearance of superficial dullness as well, while the left-sided superficial dullness may completely disappear in this case. The absolute magnitudes of the displacement of superficial and deep cardiac dullness when lying on the side vary greatly among individuals. When transitioning from a lying to a sitting or standing position, no clear difference in the shape and size of cardiac dullness is determined by percussion. Under certain circumstances, deep percussion of the heart, even technically perfectly performed, does not give precise results, which depends on the abnormal covering of the heart by the lungs in emphysema, when cardiac dullness is easily determined in smaller dimensions than is actually the case. Very significant reduction and even complete disappearance of cardiac dullness can occur due to the covering of the heart by air in pneumothorax, especially left-sided, in pneumopericardium, and mediastinal emphysema. Then, the strong development of mammary glands in women and the significant development of the subcutaneous fat layer in obese individuals can in an insurmountable way hinder proper percussion of the heart. Also, deformities of the chest wall can naturally more or less hinder deep percussion of the chest. An increase in the dullness of the heart, both superficial and deep, can be observed with a normal heart size, primarily with significant displacement of the diaphragm upward, when the heart takes a more horizontal position and due to reduction of pulmonary boundaries becomes less covered by the lungs. Then, retraction of the lungs in the development of cicatricial processes in them can lead to both an increase in the entire cardiac dullness and of certain parts: for example, cicatricial contraction processes in the left upper lobe can lead to an increase in cardiac dullness upward. Infiltration or atelectasis of the parts of the lungs adjacent to the heart can also lead to an increase in dullness in the area of the heart. All these phenomena can be correctly interpreted only when taking into account not only the results of percussion but all other methods of investigation and the entire clinical picture of the disease. Especially significant increase in cardiac dullness, not depending on a change in the size of the heart itself, is caused by effusion into the pericardial sac (see Pericarditis). For differential diagnosis between effusion and heart enlargement, the disappearance of visible and palpable pulsation in the area of the heart and the distinct increase in the area of dullness in the sitting or standing position in effusive pericarditis is important. Then, the stretching pericardium displaces the lungs to the side and brings together or even coincides the absolute and relative dullness of the heart, which is also a characteristic sign of effusive pericarditis. An increase in cardiac dullness due to enlargement of the heart itself can depend on an increase in the volume of the entire heart or its individual chambers. Anatomically, the heart enlarges due to hypertrophy of its walls, due to dilation of its chambers, and finally these two factors very often combine together. But with percussion, pure hypertrophy does not give any definitely detectable increase in cardiac dullness, because the increase in size is too insignificant. Only when dilation is added to hypertrophy can percussion establish the expansion of the heart's borders. Thus, the degree of dullness determines the degree of dilation of the heart. When heart enlargement occurs, first an increase in relative dullness is detected, but since the enlarged heart lies closer to the chest wall, the borders of the lungs are displaced and an increase in absolute dullness also occurs. Enlargement of the left ventricle leads to expansion of cardiac dullness to the left, and with a more significant degree of enlargement, the borders of dullness along with the cardiac impulse spread not only to the left but also downward. The right border remains unchanged in this case, and the upper border shifts upward only in cases of very significant enlargement of the left ventricle. The effect of enlargement of the right ventricle on cardiac dullness can only be understood by taking into account a series of anatomical relationships. The right ventricle lies on the diaphragm, where it slopes from right behind to left forward, and with its anterior surface is adjacent to the chest wall. When its volume increases, it encounters some resistance on the right due to the aforementioned slope of the diaphragm and from the side of the right atrium fixed by the great veins, and from below from the side of the diaphragm supported by the liver. Due to all this, when the right ventricle enlarges, the heart border increases mainly to the left and upward. Exceptional or significant enlargement to the right is observed when the right atrium plays a significant part in the enlargement of the heart; this is quite understandable, since the right border of the heart is formed exclusively by the right atrium. The left atrium lies so far on the posterior surface of the heart that only with strong dilation does it protrude sufficiently forward to be detected by percussion. It gives an increase in cardiac dullness mainly upward. When examining the great vessels, it must be remembered that the superior vena cava lies very deep and is completely inaccessible to percussion. The pulmonary artery arises from the right ventricle posteriorly, is covered by a significant layer of lung tissue, and moreover rarely gives a significant increase in its size, which is why it also little lends itself to determination by percussion. Only the aorta in its ascending part and in the area of the arch lies not far behind the sternum and is accessible to percussion. The descending part of the aorta is located deeply and is also inaccessible to percussion. Percussion of the aorta is performed in the lateral dimensions along the second intercostal space on the right and left toward the sternum, and with respect to its upward projection along the sternum from the jugular notch downward. Under normal conditions, the dullness of the aorta does not extend beyond the edges of the sternum laterally and upward beyond the angle of Louis. The transverse diameter of the aorta, determined by percussion, is normally 4 to 6 cm, depending on the individual's build. When percussing the abdominal cavity, it is necessary to take into account above all that the gastro-intestinal tract, occupying most of it, has the ability to give especially easily continuous vibrations on percussion. Therefore, even comparative percussion, and especially delimited percussion, should be performed very lightly and quietly. In this case, definite boundaries of dullness in the abdominal cavity are given only by its massive organs (see Abdomen-percussion of the abdomen, and Stomach-methods of investigation). Percussion of the liver. The upper border of the liver is at the same time the lower border of the right lung, so everything said about the lower border of the right lung directly applies to the upper border of the liver. The lower border of the liver is determined by percussion along four lines: along the midaxillary, midclavicular, median, and left parasternal lines. In the normal state, the border is at the tenth rib along the midaxillary line, coincides with the costal margin along the midclavicular line, is 5-6 cm below the xiphoid process along the median line, and is located at the attachment of the fifth left costal cartilage along the parasternal line. Dullness over the area of the liver can decrease and increase in its dimensions. A decrease in the size of dullness over the liver depends in only rare cases on a decrease in the size of the organ itself (acute yellow atrophy of the liver), but usually depends on the accumulation of gas in the abdominal cavity in perforative processes or most often in the intestine, because distended intestinal loops, penetrating between the abdominal wall and the liver, give a clear tympanic sound and often lead to the complete disappearance of hepatic dullness. An increase in dullness from the liver occurs either from its displacement downward, for example in pleurisy, emphysema, and right-sided pneumothorax, or from its enlargement, or from both causes together. Clarification of these various circumstances is often possible only with a detailed analysis of the entire symptom complex of the disease in each individual case. Percussion of the spleen. The technique of percussion of the spleen is determined by its anatomical position. The spleen lies in the left hypochondrium parallel to the course of the ribs, and its long axis in most cases coincides with the tenth rib. The anterior 2/3 of the spleen, directly adjacent to the ribs, are accessible to percussion.

The posterior third of the spleen is covered by the lungs and is inaccessible to percussion. Normally, the anterior edge of the spleen lies behind the costo-articular line, i.e., the line connecting the ribs with their costal cartilages, and is recognizable either by the tubercles often present at the junction of the ribs with their cartilages, or in their absence, by connecting the sterno-clavicular joint with the anterior end of the XI rib with a straight line. Percussion of the spleen is best performed in the diagonal position on the right side to cause the contents of the stomach to move away from the left hypochondrium, which in the supine position can alter the result of spleen percussion and be a source of erroneous conclusions. When performing the percussion itself, first the costo-articular line is drawn and percussion is begun, retreating 4-5 cm posterior to it from the VI-VII ribs, percussing from top to bottom along a line perpendicular to the ribs. After determining the upper border, percussion is begun in the same way from below from the left lumbar region parallel to the costo-articular line and perpendicular to the XI rib. After determining the transverse diameter of the spleen, its longitudinal diameter is percussed, going perpendicular to the middle of the transverse diameter from the front of the left hypochondrium and behind the posterior axillary line. Normally, under normal conditions, the dullness from the spleen extends from the IX-XI ribs and is located behind the costo-articular line. Due to the fact that the position of the spleen can easily change due to its displacement when the adjacent organs - the stomach and especially the intestine - change their filling, it is always necessary to determine the size of the spleen in centimeters - longitudinal diameter 6-8 cm and transverse diameter 5-7 cm. In normal conditions, the change in the position of the spleen can sometimes be so significant that it becomes completely inaccessible to percussion. Then with significant accumulations of fluid in the abdominal cavity and in the left pleural cavity, the dullness in the left hypochondrium makes the determination of the spleen by means of percussion completely impossible. -Percussion of the bladder. Finally, by means of percussion, it is possible to determine an abnormally distended bladder, which, according to Müller (F. Müller), gives an arched, upwardly limited dullness above the pubis in women with 500-600 cm³ of fluid, in men - 350-500 cm³. This dullness has decisive importance for determining the presence of overfilling of the bladder only when it disappears after spontaneous or artificial emptying of the bladder.