Percussion and auscultation as diagnostic aids. A manual for students and practitioners of medicine

Front matter

I

I

I ^y "<*i I

Chapter II. Height Of The Sound

There are fewer conditions or qualifications in the height of the sound than in its intensity.

(1) The smaller the vibrating mass that is the volume of the air-containing parenchyma, the higher is the sound; the greater the mass, the deeper the sound. A part of a lung gives a much higher sound than a whole lung. If, in case of extensive pleuritic exudation, the apex only of the upper air-containing lobe can still vibrate, then the sound over it is muffled, non-tympanitic, and higher than on the other side. Small, superficially situated air-containing parts of the lung, which are found in the midst of the parenchyma emptied of air, also give a muffled, high sound. Over thin layers of lung-substance, under which lie non-air-containing organs, like the liver and heart, the sound is likewise deadened and higher.

Scoda considered the only cause of his full and

empty, deep and high sounds, to be the volume

of air contained in the thorax. "Wintrich has

shown that there is still another condition, viz.,

(2) The degree of tension of the parenchyma of the lungs, or of the walls containing the air. The greater this tension, the higher is the sound; the less the tension, the deeper is the sound. When the walls vary in size but have the same tension, the smaller has a higher sound than the larger. For example, he adduces : let the healthiest person after deep inspiration cough strongly, with the glottis closely contracted, and percussion meanwhile be made, we shall be astonished to hear how much more muffled, shorter, weaker, and higher the non-tympanitic sound appears in those parts of lung-structure thereby greatly compressed in comparison with that heard in undisturbed respiration. He proved this by placing weights upon a portion of lung, and thus producing different degrees of tension. This condition also admits of pathological proof. In pleuritic exudation the muffling of the sound begins behind and below, and reaches higher there than hi front, which circumstance is the result of the horizontal position of the patient. The lower parts contain no air, the upper parts but little. In this condition the sound from below the clavicle of the affected side, which was at first loud, deep, and tympanitic, is rendered dull in a downward and lateral direction. The question arises, Whence this depth of sound ? On the affected side the volume and tension of the lung have decreased. Diminution of the volume increases the height of the sound, diminution of tension increases the depth of the sound.

Since it is deeper now, the diminution in tension must be the greater. The longer the sound-wave, the deeper the note produced. The longer the sound-wave, the less frequently are its vibrations repeated in a second, and consequently the smaller is the number of vibrations. The number of vibrations, or the height of the sound, is equal to the tension divided by the volume, or h = |. If the diminution in volume is greater than the diminution in tension, the sound becomes higher. This finally occurs where the exudation increases. Then the sound underneath the clavicle of the affected side is higher. The same is true in pneumonia. In the later stages of pneumonia, since it is usually located behind and below, the larger posterior part of one lobe becomes hepatized, but only the smaller anterior part; anteriorly, the greater part is still air-containing. We hear, then, over the affected lobe, anteriorly, a loud, high, tympanitic sound. The air-cells, posteriorly, become distended by fibrinous exudation, and so cause, anteriorly, through compression, diminution of volume and decrease of tension. The former surpasses the latter, therefore the sound is higher. In the earlier stages of pneumonia, when the exudation is not yet so abundant, the diminution of tension is in excess of the diminution of volume. Hence in this stage the sound is deep. The dependence of the height of the sotfnd upon the degree of tension also shows itself in dry catarrh. In deep inspiration the sound is also higher than in expiration. In inspiration the volume as well as the tension is increased. By the increase in volume the sound ought to become deepened; but, since it becomes higher, the increase of tension must be greater.

From the two named conditions of the height of the sound we deduce the following diagnostic aids :

(1) It cannot be decided with certainty that there is increase in size because there is deepening of sound ; there may even be diminution in size.

(2) It can be decided with certainty that there is diminution in size, if the high sound remains constant and is at the same time muffled. This is the case in tuberculosis.

(3) Further, the height of the sound depends upon the length of the vibrating column of air. The longer the column of air, the deeper is the sound; the shorter it is, the higher is the sound. Therefore, in pneumothorax the sound on the affected side is tympanitic and deep, and the deeper it is the more extensive is the pneumothorax.

(4) The greater the opening of the sounding space, the higher is the sound. When we percuss a column of air in a vessel, the greater the opening it may Save, the higher is the sound produced. If orifices are made in the vessel, the tympanitic sound becomes higher. ( Wintrich.) In case of tuberculous caverns the sound becomes much higher if the patient holds his mouth open during percussion. By means of the trachea and glottis the caverns are in free communication with the opening of the mouth ; the opening of the mouth is also, to a certain degree, the outlet of the same. Wintrich diagnosticated caverns from this circumstance, but yet he himself cites cases in which the tympanitic sound is sometimes high and sometimes deep. "When the superior anterior part of the lung is completely hepatized, or when the lung-tissue becomes strongly compressed by a pleuritic exudation situated anteriorly around the apex of the lung, the trachea is in the exact condition of a cavern, since the lung-tissue no longer controls the sound ; but probably it propagates the shock of the percussion. He says, further, that this difference manifests itself even in the extremely rare case when a circumscribed pneumothorax stands in connection with the trachea and oral cavity by means of a large fistulous orifice.

Chapter III. The Timbre Or Quality Of The Sound

A. The Tympanitic Timbre.

The tympanitic timbre may be distinguished by means of a ringing sound, which, approaches to, or resembles, a musical tone. The difference between intensity and highness is most readily to be distinguished in this sound. This tympanitic sound may be represented by holding the pleximeter over a tube filled with air and percussing upon it with the percussing hammer. Scoda found that a distended stomach gives a tympanitic sound when its walls have a slight degree of tension, but that this timbre disappears in proportion as the tension of the walls is increased by inflation. He maintained that the percussion sound is, without exception, tympanitic if the walls which inclose the air are not tense; but in increased tension of these walls the percussion sound appears less or not at all ty mpanitic, and also more dull. Thus, when the tympanitic sound can be heard on the thorax, we can infer that the tension of the parenchyma is lessened. In a normal condition the tympanitic

36 THE TIMBRE OR QUALITY

sound can be heard in the crescentic space of the thorax (of which hereafter), and on the abdomen over the stomach and intestinal canal, so long as the gas within the walls does not make them too tense. If over this part the tympanitic sound cannot be heard, there must exist an abnormal condition. There is then either a great tension of the walls, on account of gaseous contents, as in meteorism, or there is fluid in the abdomen, or the stomach and intestines are filled with fluid or solid matters.

In an abnormal condition the tympanitic sound is heard on the thorax in the following cases :

(1) In pleuritic exudation the sound below the clavicle of the affected side is loud, deep, and tympanitic. The diminution of tension, which, as cited in regard to height of sound, is the cause of the deepness of the sound, also produces the tympanitic timbre.

(2) When in pneumonia the posterior part of the lower lobe is hepatized, a loud, deep, tympanitic sound is heard, beginning anteriorly. Here, too, we find diminution of tension. The volume of hepatized lung becomes so enlarged by fibrinous exudation in the air-cells, that, for example, the upper lobe of the right lung, which, in its normal state, reaches only to the third intercostal space, when hepatized may be found reaching even to the sixth rib. Through this

OF THE SOUND. 37

enlargement of the posterior half the anterior part becomes compressed, and hence the parenchyma loses its tension.

(3) Over hollow cavities and caverns, which contain air and are situated superficially, as in dilatation of the bronchial tubes, the tympanitic sound likewise appears; that is, the sound of the air contained within them, in case there be diminished tension of their walls and of the surrounding parenchyma. In case this parenchyma is normally filled with air, the tympanitic timbre is absent. In tuberculous caverns the neighboring tissue is generally infiltrated and void of air, therefore the tympanitic sound may usually be heard over them. Still, these caverns must be of a certain extent, which cannot be exactly computed. When small caverns of the size of a bean or hazel-nut exist in the apex, then the sound, in consequence of the infiltration of the surrounding tissue, frequently becomes muffled and non-tympanitic. If several small cavities lie near one another, then the non-tympanitic sound may be normally just as loud as on the healthy side, or even louder. In such cases the certainty of diagnosis is aided by auscultation.

If the nose and the mouth of the patient be tightly closed, and at the same time the diaphragm be caused to contract, the tension of the walls becomes much increased, and the tympanitic sound over the caverns disappears. When

4*

38 THE TIMBRE OR QUALITY

a mass of mucus, pus, or blood shuts off a cavern from a bronchus, this immediately causes an increased tension of the walls, which destroys the tympanitic sound. If the cavities are filled with mucus, or other substance, then of course the tympanitic sound disappears, but it returns again as soon as the fluids are removed by expectoration.

(4) In pneumothorax the tympanitic sound of the air is heard when the wall of the thorax has not too much tension. But if the intercostal spaces are closed by the pressure of air in the pleural cavity, the tympanitic sound disappears. In extensive distention of the abdomen from meteorism, for the same reason, that — is, from too great tension of the walls, — the previous tympanitic sound disappears.

(5) In acute oedema of the lungs the tympanitic sound also occurs occasionally, even when the lung is emphysematous, because a diminution of the tension of the parenchyma is combined with the watery infiltration.

Caverns and pneumothorax excepted, the tympanitic sound leads us to the general conclusion that the tension of the parenchyma of the lungs is diminished. The cause of the diminution of tension or of the tympanitic sound, in any given case, can only be determined by the help of other physical symptoms.

OF THE SOUND. 39

B. The Metallic Timbre.

The metallic sound can be heard very distinctly in the percussion of empty vessels, either open or closed with a cover. That this sound differs from the tympanitic sound, may be proved by this, that a tensely distended bladder no longer gives the tympanitic sound, but it may give the metallic sound, which, a partially distended bladder may also give. Wintrich was the' first to state the conditions of the metallic sound. (1) The walls of the sounding space must be so smooth that there may be a uniform reflection of sound from wall to wall. Still, an absolute smoothness of surface is not necessary. But irregular surfaces of unequal thicknesses prevent the formation of the metallic sound. (2) The greatest diameter of the sounding space cannot be less than about 1J inches. This is the principal reason that caverns do not emit the metallic or ringing sound. For the smaller the sounding space, the higher and weaker is the metallic sound ; for instance, in quite small elastic balls it is only perceptible when they are'held close to the ear.

The reason that in pneumothorax the metallic sound is often heard only in percussion on certain spots, arises from the fact that only by percussion over these places can the column of air in its greatest diameter be set in motion.

40 THE TIMBRE OR QUALITY

When the walls are thick, the metallic sound produced within is not distinctly heard from without, and the sound is louder from unobstructed than from closed passages.

In addition to this, Traube has discovered that the metallic sound is not heard when the tension of the. air becomes too great. In pneumothorax the metallic sound is always to be heard post-mortem ; but if the tension of the air in the thorax be made greater by the upward pressure of the diaphragm, this sound disappears. It is not in reality the air which destroys the metallic sound, but the tension of the soft parts, resulting from the presence of the air. This is also the reason that the metallic sound is heard on the cadaver, but, on the contrary, seldom on the living body. After death, the temperature being lessened, the tension of the air and of the soft parts also becomes diminished. Hence it follows, too, that intercostal spaces, which in life were full, after death become depressed.

On the living body the metallic sound is seldom heard, because usually one of the conditions named is not filled. It can be perceived:

(1) In pneumothorax. But it is usually necessary during percussion to auscultate at the same time with the stethoscope ; first, because the cavity of the pneumothorax is usually closed, and also because the walls of the thorax are for the most part too thick to allow much of the sound produced within to pass through them.

OF THE SOUND. 41

(2) In case of caverns in the lungs. If these are closed, they cannot have a diameter of less than six centimetres, or about 2| inches, in order to produce the sound. Open caverns, that is, such as have free communication through a bronchus with the atmospheric air, still give the metallic sound even with a smaller diameter.

Still, such communication is unfrequent; the bronchus often becomes obstructed, so that the metallic timbre can only appear temporarily. The presence of fluids in the caverns does not prevent the production of the metallic sound, nor, according to Piorry, are they necessary to it. Still, of course, the sounding space must not be too much diminished by the quantity of fluid. In the case of small caverns, the metallic sound can be better heard by bringing the ear close to the thorax (that is, in superficial caverns) or near the mouth of the patient.

The height of the metallic sound, unlike that of the tympanitic, is not varied by opening and closing the mouth, but is always in proportion to the height of the vibrating column of air. The smaller this is, the higher is the sound.

The Sound of a Cracked Kettle {Bruit de potfele). — The Sound of Clinking Coin.

The term " Sound of a Cracked Kettle" is used by Laennec, because there is a resemblance

42 THE CRACKED-KETTLE SOUND.

to the sound produced by striking a cracked kettle. It was formerly considered as a pathognomonic sign of caverns; but it is not so. It is but seldom heard over caverns, because in such a case the conditions necessary to its production are usually wanting. This arises from the fact that by the force of the percussion the thoracic wall is pressed a little inward, and the space of the cavern made smaller. The sudden passage of the air out of the cavern into the much narrower bronchus produces this sound. For the production of this sound, it is also necessary that the thoracic wall be thin and yielding, the cavern tolerably large and situated superficially and in free communication with the bronchus. Of course these conditions are fulfilled in the case of the smallest caverns. When the percussion is feeble and the ear is held at some distance from the thorax, a feeble clanging sound can easily be heard, which becomes more perceptible if the patient open the mouth.

The cracked-kettle sound appears occasionally in the case of superficially situated caverns ; in pneumonia in the region of the tympanitic sound; in pleuritic exudation in the region of the large bronchi; even in simple bronchitis and in completely healthy persons, particularly with children. According to Traube, it is produced by the passing of the air out of a larger space through a narrow opening. In children the air-containing

THE CRACKED-KETTLE SOUND. 43

space is represented by the whole lung, and the narrow opening by the glottis. The clanging sound is heard most frequently under the clavicle, and with it usually a dull, high sound. If the latter appears with it, it is safe to decide that there are caverns. A strong, short percussion stroke is best adapted to bring out the clanging sound. A quite similar sound arises, besides, from the unskillful placing of the pleximeter when a little air remains under it,

Wintrich introduces still another modification of the cracked-kettle sound (bruit de pot fele), which may be heard by striking on the thorax of any individual when singing, speaking, or crying. His explanation is this : that the regular vibrations of the vocal chords in speaking, singing, and crying, which by the pressure of the compressed air become disturbed and irregular, do not, properly speaking, give a tone, but a sort of clinking noise. In the same way he explains the ringing sound, like that of coin, entirely similar to that of the above-named clinking sound, which may make its appearance in hollow cavities, and which yields a metallic sound whether the cavities be caverns or the lower part of the trachea. The latter produces the metallic sound under the same conditions as the tympanitic. (Williams's Tracheal Sound.) Thus both sounds are a modified metallic ring, resembling that of the clinking sound, but of momentary duration.

44 THE RELATIONS OF PERCUSSION

The hydatid trill, which Piorry laid down as characteristic of the sac of the Echinococcus, is probably a feeling of fluctuation produced during percussion. It can be perceived in the same manner when one shakes such a sac back and forth in the hand.

The Relations of Percussion to the Normal Thorax.

In the infra-clavicular region, between the clavicle and the third rib, the percussion sound is loud and deep ; it is louder here than anywhere else on the thorax. This is chiefly to be explained by the greater thinness of the thoracic wall; for this reason it also appears less loud when there is good development of the pectoralis major in the outer parts of this region. In the fossa supra-clavicularis the sound is likewise loud, and, indeed, somewhat louder than in the outer part of the infra-clavicular region ; in respect to depth, it is not quite so deep as in the latter case. But, if the sound in the fossa supra-clavicularis seems dull in comparison with that in the infra-clavicular region, the former must be considered in an abnormal state. In this region it is necessary to place the pleximeter close to the clavicle, over the outer edge of the sterno-cleido-

TO THE NORMAL THORAX. 45

mastoideus, otherwise the sound becomes accompanied by a weak tympanitic sound.

Near the sternum the clavicular region gives a less loud and deep sound than the infra-clavicular region ; on the acromial half of the clavicle the sound is duller than on the sternal portion. For percussion in this region, it is especially necessary, as almost everywhere else, to compare corresponding points; that the shoulders stand upon the same level, and that the hammer be made to strike the pleximeter in the same direction on both sides.

These three regions always deserve special attention, because tuberculosis generally begins on the apices and upper parts of the lungs, and there first becomes of diagnostic significance, often, indeed, at a time when Therapeutics can still effect much.

The mammillary region, extending from the infra-clavicular region to the fourth rib, inclusive, gives a deep, non-tympanitic sound, somewhat less loud than beneath the clavicle. The small degree of dullness in sound may be accounted for by the stronger development of the lower part of the pectoralis major, and by the skin being somewhat thickened by adipose structure, — the female breast not being at all considered. Under the fourth rib the sound becomes still a little less loud and high, and, from the sixth rib downward, intensely dull. The bound-

46 THE RELATIONS OF PERCUSSION

ary between the lesser and greater dullness marks the margin of the lung. At the left the perceptible dullness of sound commences at the third rib, and proceeds thence downward, attaining its greatest breadth in the fifth intercostal space (cardiac dullness). The dullness is greatest near the sternum. In deep inspiration and in emphysema this dullness becomes less, and in emphysema may wholly disappear.

Under the sixth left rib the sound, a little dulled by the left lobe of the liver, is high and clearly tympanitic. The tympanitic sound is derived from the air-containing stomach, which influences the sound. This space of tympanitic timbre, the only one in the whole thorax, is called the crescent-shaped region. It has normally a breadth of three inches ; by contraction of the left lung it becomes greater, by hepatization and pleuritic exudation less. Exudation not merely presses the diaphragm downward, but it also presses the stomach downward and to the right. Then the tympanitic timbre disappears, and the zone shows a strong degree of dullness. The beginning of absorption is first indicated by 'increase in the breadth of this space.

The sternal region can be divided into four different sections : the sound of the manubrium is loud and deep, but less loud than on the sternal part of the infra-clavicular region. No lung-substance lies under the manubrium, but only

TO THE NORMAL THORAX. 47

the anterior edges of the lungs reach clownward along its lateral margins until they almost touch each other on a level with the second costal cartilage. On account of the nearness of the edges of the lungs, the sound of the manubrium is not wholly dull.

On the upper part of the body of the sternum the sound is more or less loud than on the manubrium, because the anterior edges of the lungs on a level with the second rib, the boundary between the manubrium and corpus sterni, almost touch each other. Cardiac dullness begins at the third rib. On the xiphoid process, under which the left lobe of the liver lies, the sound shows a great degree of dullness ; the stomach occasionally imparts to it a tympanitic tone.

The marginal regions of the sternum impart a loud and deep sound as far as the fourth rib ; between the fourth and eighth ribs it is higher and a little less loud. In the right marginal region the dullness of sound produced by the liver begins at the seventh or eighth rib. On the left, under the seventh rib, a slightly tympanitic sound occurs, which at the ninth rib is rendered dull by the spleen. Between the sixth and seventh ribs, on the left, lies the lower margin of the lung ; it is, therefore, to be inferred that with this margin the high tympanitic sound ceases.

The percussion sound is in general much duller on the back than on the front of the body,

48 THE RELATIONS OF PERCUSSION, ETC.

on account of thick muscular layer. It indicates the greatest degree of dullness over the shoulder-blades, and next in the supra-spinous regions, where it is also higher.- These regions have the same importance as the clavicular region in diagnosis of tubercular disease. Especially must attention be paid to the shoulders being held on a level, and to the percussion of exactly corresponding points : for near the acromion the dullness is much more perceptible than near the spinous processes. The inter-scapulary region gives a less dull sound than the scapulary region ; the greatest degree of dullness is indicated on the vertebral column. The sound of the percussion is louder and deeper in the infra-scapulary region than anywhere else on the back, but not so loud and deep as on the front of the body. Towards the lower edges of the lungs, near the eleventh rib, the percussion sound is accompanied by a slight tympanitic sound, produced by the air-containing organs in the abdomen. In what manner the mobility of the edges of the lungs can be investigated by the sound of percussion in inspiration and expiration, has been already mentioned.

Pectoral Fremitus.

By the term pectoral fremitus we are to understand certain sensible vibrations of the thorax, which are transmitted by the voice to the thoracic walls. There are also other loud sounds on the. thorax which may be felt, viz., rattling, wheezing, and frictional; but they do not belong under this head.

The fremitus is best tested by the points of the fingers. By using the whole hand one often touches points possessing different degrees of vibratory power.

The pectoral fremitus is much stronger in a deep than in a high voice, and in a whistling voice we can scarcely perceive it. The farther from the glottis palpation on the thorax be made, the weaker the fremitus appears, as may easily be conceived. But normally it is nowhere wanting except in weak or high voices, particularly those of women and children ; it may fail on the lower or even on the upper part of the left portion of the breast. In old people the fremitus is usually stronger, according to Scoda for this reason, that the bronchial cartilages increase in thickness and hardness with age. On the right side the fremitus is absolutely stronger than on the left. On the right side its weakening has much more significance than on the left. This difference is perhaps to be explained in this way :

5* that the right bronchus is wider and shorter, and passes off at a shorter angle, than the left one. The fremitus is very weak on the shoulder-blades, especially on the spine of the scapula, and also on the manubrium of the sternum, under which no lung-structure lies. Over the spleen, liver, and heart the fremitus is wholly wanting. When the patient is lying down, the fremitus is strongest; it usually changes with the position, and therefore he should always be examined in the same condition. It becomes weakened through everything which interferes with the transmission of the vibrations through the vocal chords.

(1) By the thickness of the thoracic wall ; on this account it is weak on the shoulder-blades and on the female mammary glands. (Edema, abscesses, extravasation beneath the skin of the thorax, also weaken the fremitus.

(2) By obstruction of the bronchi by matter, blood, or mucus.

(3) By pneumothorax.

(4) By large tumors, abscesses, and gangrenous destruction of the lungs, if these affect a large part of the lungs.

(5) By pleuritic exudation. Here, as in pneumothorax, it may increase above fluids or gases, where the tympanitic sound appears, but corresponding to the site of the fluids it is much weakened. The pectoral fremitus is of great importance in the diagnosis of limited pleuritic exudation, which is sometimes difficult to distinguish from pneumonia and induration of the connective tissue. When the fremitus is diminished or obliterated over the point of dullness, it is conclusive proof of pleuritic exudation ; if it manifests itself normally or augmented, it is proof of thickening of the lung-tissue by hepatization or induration of the connective tissue. In pleuritic exudation upon the right side it may, however, occur that, after absorption has commenced, the fremitus on the upper part of the region of dullness equals that upon the left side. The fremitus becomes stronger :

(1) When the parenchyma and walls of the bronchi are thickened either from hepatization, tubercular deposit, chronic induration, or from compression resulting from chronic collections of gas or fluid in the pleural cavity.

(2) Caverns strengthen the fremitus in the same way when their walls are thickened. But they must be situated tolerably near the periphery, contain air, and either communicate freely with the air in the trachea, or be cut off from the same by a moderate stratum of lung-structure.

In regard to the rhonchi which may be felt, as rattling, whistling, wheezing, and rubbing, it may be added, further, that these sounds arise from the vibration of viscid portions of mucus, not always existing in the place where the sound is to be heard or felt. It is often so strong as to transmit itself from the larynx over the whole thorax. A strong fit of coughing, which removes the mucus from the larynx, annuls the fremitus in it as well as in the thorax. A widely extended fremitus by no means proves a diffuse collection of mucus.

The pleuritic frictional sound is also often perceptible to feeling. It occurs when false membranes on the costal and pulmonary pleura glide over each other in breathing.

The gurgling in the abdomen is produced in the intestines by bubbles of air passing through fluids. It is mostly perceptible to touch, as in ileo-typhus in the ileo-caecal region.