A manual of physical diagnosis

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Preface To The Sevei^th Edition

Recent advancements in the laboratory side of diagnosis have discouraged the acquisition of that thoroughness and skill in the employment of simpler methods which were so essential to the earlier masters of clinical medicine. Even among instructors the disposition to subject every difficulty in diagnosis to the a:-ray, polygraph, electrocardiograph, etc., before the older means of examination have been exhausted, is daily developing. This tendency to adopt the dramatic, and slight the direct use of his unaided senses, doubly appeals to the student, for he naturally fails to foresee how often in practice he will lack the advantages of such apparatus.

The particular need which this manual was intended to fill, and which it is expected that it will again fill, is the demand of the student and of many graduates in medicine, for simplicity, directness, exactness, and skill in dealing with physical signs in health and diseases.

In preparing the present edition it has been the purpose of the Editor to retain, and as far as possible to augment, by his additions and modifications, those features which have heretofore so strongly appealed to the student and the general reader. To this end a iv PREFACE

chapter on the Physics related to the subject has been introduced. It is hoped that it will assist the student to correlate the phenomena of auscultation and percussion with the principles he learned during his academic courses. Certain minor methods of examination, as Inspection, Palpation, etc., have been brought into greater prominence than the distinguished Author originally accorded them. /

Our knowledge in ^no phase of internal medicine has progressed more rapidly during recent years than in Cardiac Disorders. Hence, special effort has been exerted to bring the chapters devoted to examination of the Heart into accord with modern ideas. The subject of Arrhythmia has been rewritten and its usual types diagrammatically presented. On page 297 a diagram has been introduced which should enable and encourage the student to visualize the auscultatory signs of cardiac disease.

Finally, the Editor would allude to the satisfaction he has felt in associating his name w^ith a work that bears the vital impress of Professor Flint's genius.

Henry C. Thacher.

New York, 1917.

Chapter I. The Physical Basis Of Auscultation And Percussion Of The Lungs

Physics of sound — Simple sounds or tones — Intensity — Pitch — Noises — Quahty or timbre — Action of resonators — ^Transmission of sounds— Percussion of bones — Soft tissues — ^Tissues containing large collections of air — Open and closed cavities — Tissues containing air in minute subdivisions — Auscultation — Transmission of sounds from bronchi through solid lung — Through alveolar tissue — Breath sounds over normal lung — Solid tumors — Pulmonary cavities and pneumothorax — Pleural effusions — ■ Adventitious sounds — Moist rales — Modification due to condition of parenchyma — Consonating rales — Dry rales — Crepitant rales — Pleural friction and pleural splashing sounds.

PHYSICAL BASIS OF PERCUSSION AND AUSCULTATION.

The more important methods of physical examination of the lungs depend upon alterations of the sounds elicited by striking upon the chest wall (percussion) and upon alterations of the sounds normally heard at the chest wall when the patient breathes, speaks or 2 whispers (auscultation). It may be worth our while, therefore, to sketch briefly the characteristics of sounds in general, and also to give particular attention in the main principles governing and modifying sounds under similar conditions than those met with in the thorax.

PHYSICS OF SOUND.

Sound is a sensation produced when vibrations reach and stimulate the ear. The human organ of hearing is sensitive to vibrations occurring at a rate of between 16 and 40,000 per second, provided they be transmitted to it with reasonable intensity. Whenever we set up vibration in a tuning-fork, drum, string, vocal cord, or what you will, these are propagated by the surrounding air in the form of rapidly alternating waves of condensation and rarefaction, which * radiate away with great velocity — in air at a rate of 11,000 to 12,000 feet per second. Should the sounding body be in contact with a solid elastic substance, the sound waves may be transmitted even better by the solid than by the air, as along the railroad tracks or iron water-pipes. The ability of solids to transmit sound waves varies Avith the mass and elasticity — the latter meaning their ability to resume their original form, when that force which altered that form ceases to act. Sound waves may also pass with varying loss of intensity from air to solid, and solid to air again — for example, through the walls from one closed room to another. The quality of the

PHYSICS OF SOUND 19

transmitting substance and the distance are as important in determining the sounds we hear as the intensity of the original vibrations.

As the pendulum is the simplest form of a slowly oscillating body, so an elastic rod fixed at one end and free at the other gives us the least complicated rapid vibrator. When two such rods of equal proportions are fixed side by side on a common base, as by clamping in a hand vise, their oscillations strengthen one another, so that they continue much longer in motion, and are therefore best suited for the production and analysis of simple sounds of a fixed uniform wave length. Such a pair of parallel rods constitutes a tuning-fork. The sound produced by them, when their regular rapid oscillation is transmitting its uniform series of waves to the ear, is called a tone. Tones are sounds of definite uniform wave length.

Intensity of Sound. — ^\^^hen we examine such a tuning-fork we find that, like a pendulum of given length, its oscillations may vary greatly in size, depending upon the force with which it is set in motion, but the number per minute is an inherent fixed characteristic of the individual instrument; and with one or one hundred tuning-forks of the same elasticity, mass and proportions, tones can be produced which may differ in quantity, but in that alone. Such differences in quantity or intensity depend merely upon the violence with which the sound waves reach the ear, and may be brought about on the one hand by altering the force with which the tuning-fork is set in motion; and on the other hand by varying the distance of the ear from the instrument, or the character of the transmitting medium. The intensity of a sound is simply the loudness with which it is heard.

Pitch. — ^With tuning-forks of different sizes the tones produced, even though they be equally loud or intense, are not alike, but differ in another attribute called pitch. We find that the smaller the forks, the more rapid the vibrations and the higher the pitch, no matter whether the intensity of the tones be great or small. Pitch depends upon the rate with which vibrations of definite periodicity or rhythm reach the ear, and is a characteristic of every such rhythmical sound or tone.

Noises. — ^When several or many tones of unrelated wave length are simultaneously produced, the resulting sound waves are irregular vibrations without periodicity or rhythm. Such non-musical sounds have no definite pitch and are called noises. Although noises have, strictly speaking, no true pitch, in physical diagnosis we are constantly comparing them in regard to this quality. In so doing we are really referring to the pitch of the predominating or of the lowest tone present in these compound sounds.

Quality or Timbre. — Sound waves of equal rate and intensity can be produced from a great number of vibrating bodies and yet even then they are not entirely alike. This is due to differences in what is called quality (or timbre) which are so great that the same notes produced on different instruments are

PHYSICS OF SOUND readily distinguished by even the most untrained ear. These striking, though indefinable, differences in quality (or timbre) depend upon the fact that our sonorous bodies do not confine themselves to the production of their single fundamental tone, but

Fig. 1. — Vibration waves of a simple tone (tuning-fork).

Fig. 2. — Vibration waves of intense fundamental tone with faint overtones (violin).

Fig. 3. — A complete musical instrument.

Fig. 4. — Human voice.

Vibration waves in which the overtones are intensified, giving a very distinct individuality to the sound.

Figs. 1-4. — Diagram of musical sound waves composed of a simple tone and of fundamental plus overtones.

add to this secondary regular tones, two, three, four, etc., times the rate of the fundamental. The violin string thus vibrates not merely as a whole but also in parts of one-half, one-third, one-fourth, etc., and the sound produced consists of not only the fundamental but also the superimposed overtones. It is the latter that give quahty to sounds; and it is on their faculty of producing overtones that musical instruments depend for their individuality.

Resonators. — Overtones and fundamental tones are magnified by the presence of a sonorous body or resonator whose wall or air-content takes up and vibrates in unison with the original tones, adding greatly to their intensity and quality. The resonator, according to its ability to intensify these overtones, is indeed far more important in contributing quality than is the vibrator itself. This is perhaps best emphasized in the case of violin bodies which vary so extraordinarily in value, although their strings are so insignificant in cost. Overtones accompany the fundamental tone of most musical sounds.

In the construction of sounding boxes or resonators for musical instruments the maker's skill is directed to producing a sounding body that will covibrate with sounds of many degrees of pitch. All elastic structure, however, have their own vibration times, and when oscillations are transmitted to them at that rate they are set in motion. This is daily seen in the laboratory when, as an ill-balanced centrifuge is gradually increased in speed, now one, and now another pipette rack, beaker or burette begins to rattle, and subsides only when the centrifuge's vibrations have altered to become more or less rapid. It is this which makes it necessary that marching troops break step while crossing bridges, and upon this same fundamental law depends the fact that, if the sound waves

PHYSICS OF SOUND 23

of one tuning-fork reach a fork, string or ball or other sonorous body of similar pitch, the latter is set in action. This law is made of practical use in analyzing sounds composed of several tones by exposing a series of resonators to the compound vibration, and noting which resonators are set in co vibration. It is also of great importance in the construction of stethoscope bells. When dealing with faint murmurs of low pitch, the old Gannet type of stethoscope not infrequently settled an argument; because the large resonating cavity of its bell intensified murmurs of that pitch. On the other hand, soft murmurs of aortic insufficiency are notorious for occasionally being far better heard by the direct ear than with the popular small-bell stethoscopes. While the complex resonators of musical instruments strengthen sounds of many degrees of pitch, the simpler resonating body strengthens a limited set of sound vibrations.

The Transmission of Sounds. — This demands the presence of an elastic medium between the point of production and the ear. In ordinary daily life the tendency of the waves to be transmitted in a straight line and the distance are the more essential factors in modifying the intensity with which they are heard. In physical diagnoses, however, we are chiefly interested in the quality of the intervening substance, for it is chiefly to determine abnormal physical conditions of this substance that we listen to the sounds at all. Transmission through any uniform medium varies with the elasticity coefficient, mass, and density of the individual substance, and in the body we may simply note that bones transmit well and that soft tissues transmit poorly, though do somewhat better if compressed, as when the stethoscope bell is applied with considerable force. Where the intervening substance is not uniform, however, a most important though less obvious factor enters — dispersion. Sound waves, like the waves of light, radiate in straight lines, decrease in intensity with the square of the distance and traverse certain substances better than others. This similarity is further emphasized by the fact that sound waves may be projected to a given spot when the point of production is at the focus of a parabolic resonator, and that they may be concentrated and focussed by properly constructed lenses of hydrogen. In such experiments the facility with which waves enter or are reflected back from the surface of the second medium depends on the quality of the said medium, and the angle of its surface. And just as a ray of light may be more diminished by passing it through a little ground glass than through many times as thick a layer of clear glass, so sounds that would be readily transmitted a considerable distance in wood are stopped by a thin layer of sawdust. The lack of penetration in each case depends upon the fact that with each change of transmission medium some of the waves are reflected backward or diverted laterally, and the intensity suffers accordingly. To limit the intensity of light the absorbing power of colors is so much more practical that the method of

PHYSICS OF PERCUSSION 25

dispersion, as in the use of ground glass, is seldom employed. In the ease of sound, however, dispersion is constantly employed, and underlies the use of carpets, padded walls, felt partition, and the like.

PHYSICS OF PERCUSSION.

With these more important laws of physics in mind, we turn now to see how they may explain the sounds obtained by auscultation and percussion.

• Percussion consists in tapping upon the chest wall and noting the sounds produced. If we strike any series of miscellaneous objects the sounds evoked depend upon the nature of the substance thus thrown into vibration, and also upon the violence with which, it is struck. As the object of percussion is to determine the physical nature of the underlying tissues, it is essential that variations due to differences in the strength of the percussion stroke must he avoided.

From a physical stand-point animal tissues may he divided into hones, soft tissues, and soft tissues containing air. On tapping, or to use the technical term, "percussing" a bone, we find that it can be made to vibrate and to give forth sounds of an intensity which varies with the force with which it is struck; of a pitch which varies with its size and shape, and of a quality which is sufficiently typical to be recognized from sounds obtained by percussion over other parts of the body. Bones are resonating hodies, and their percussion yields a fairly typical sound which we call a bony note or osseous resonance.

Percussion of soft tissue, whether muscle, fat, liver, etc., on the other hand, yields no resonance. This absence of resonance, called flatness, is because such tissues have considerable mass but very poor elasticity. Collections of fluid are equally devoid of resonance to percussion. Not only do soft tissues yield no resonance, but they also impede transmission of the percussion stroke to an underlying resonating body, and impede the return of sound waves from the resonator to the ear. A layer of rubber will mufile the loudest drum.

Percussion of Air-containing Tissues. — Percussion yields its greatest information in dealing with soft tissues containing air. Over a large air-containing cavity the percussion note varies in intensity with the force employed and with the amount of intervening tissue. Therefore when constant force is used, the intensity enables us to estimate the amount of tissue intervening. Thus in percussion upward on the abdomen the edge of the liver is detected by the decreased intensity over that part of the stomach, or colon, which it overlies. With very light percussion, just sufficient to produce resonance over the exposed portion of the gut or stomach, the muffling effect of a very thin layer of liver may be detected. In ordinary work, however, the percussion of the lower liver margin is usually made out 2 or 3 cm. higher than the true edge.

On the other hand, the pitch over such cavities depends

PHYSICS OF PERCUSSION 27

entirely upon their size. The difference between small intestine and a colon is detected by the abrupt fall of pitch on passing to the larger cavity. Ordinarily the air collections within the body are surrounded by elastic walls under moderate tension, and the sounds obtained by percussion are due to both air content and containing wall vibrating in unison. Should the air, however, be under high tension, the elasticy of the wall is impaired so that it has little resonance of its own and also even fails to transmit the vibrations of the air within. Thus, rare cases of pneumothorax in which a valve-like perforation of the lung allows air to enter but not to leave the pleural cavity, may give a dull note, instead of the usual increased resonance. This decreasing resonance, as the pressure within a cavity rises, can be illustrated by percussing the moderately and then the forcibly distended cheek; or better still, a pneumatic tire during inflation.

Another factor occasionally enters into consideration in percussion over cavities. An organ pipe with open ends produces tones of twice the number of vibrations as that of the same pipe with the end closed. The leather bottle of the pool table on percussion is thus found to give a note of lower pitch when its neck is corked. Percussion of the cheek with the lips alternately opened and closed yields the same result. And where a pulmonary cavity communicates freely by a widely open bronchus, this change of pitch may again be frequently demonstrated by having the patient alternately open and close his mouth during percussion.

On percussing a beaker filled with effervescing liquid we obtain a beautiful drum-like (tympanitic) sound; while from a beaker of plain water no note is elicited. The difference is evidently due to the presence of numerous, though minute, air bubbles in the former. Similarly a pan of raised dough ready for baking gives a tympanitic note, quite like that obtained over a moderately tense, inflated bladder of similar size. With this in mind we might expect the J normal lung to yield sounds on percussion of the same drum-like, musical character. On examining the relaxed lung removed from the body this tympanitic note is found, but on percussing the normal chest a sound of good intensity but entirely different character, called pulmonary resonance (vide p. 74), is obtained. That the difference is not due to the chest wall is readily demonstrated by the percussion of a lung removed from the body and then inflated to its original size. This inflated lung gives, not a tympanitic note, but the peculiar sound called normal pulmonary resonance. This is because the tissue fibers of the relaxed lung are no more capable of maintaining a vibration than are the slackened strings of a violin; and merely follow the vibrations of the air contained within them. The note obtained over a relaxed lung is therefore identical with that found over the air-containing water or dough — tympanitic and varying in pitch with the size of the organ. On inflation, however, the stretched

PHYSICS OF PERCUSSION 29

lung fibers add their own vibrations to those of the air content; and the composite sound elicited is now no longer a drum-like tone, but a non-musical noise, to which, in the absence of any descriptive term, the name normal pulmonary resonance is applied.

It is interesting to note that when the pan of risen dough is baked, the loaf of bread yields no longer a tympanitic note, but a sound very similar to normal pulmonary resonance; because its air content is now subdivided by elastic partitions capable of maintaining vibrations of their own.

The Strength of the Percussion Stroke. — This may influence the sound elicited not only in intensity but also in quality. This does not apply in such simple resonating bodies as tuning-forks or strings. But if a thick-walled box is very lightly struck, we may only set in vibration the immediate superficial layers of the wood, and would therefore be unable to recognize the presence of the cavity within. To detect the latter, sufficient force to set it in vibration must be employed. Therefore in determining the height of the liver dome (liver dulness), where we are contrasting the sound produced by chest wall and a thin layer of lung with that produced by chest wall plus a much deeper layer of lung, the percussion stroke should be forcible enough to arouse vibrations in the deeper tissue. On the other hand, a heavy stroke sets in motion not only tissues deeper beneath it, but also those over a wider surface. Even 1 or 2 inches below the right pulmonary border a sufficiently heavy stroke may spread its vibrations to the distant lung or colon, yielding dull pulmonary resonance or tympany instead of flatness. For this reason in determining the physical condition of superficial tissues light percussion, just sufficient to arouse vibrations in those tissues, is essential.

PHYSICS OF AUSCULTATION OF THE LUNGS.

Transmission of Voice, Whisper, and Breath Sounds Through Solid Tissues. — On listening over the larynx when the patient speaks, loud, clear-cut voice- sounds are heard with the words perfectly recognizable. Behind over the cervical vertebrae the same clearspoken words are audible, though less intense. In either case the sounds are conducted well by the intervening tissue, and differ only in intensity, depending on how great a distance they have had to traverse, but not in any other respect. If we listen over an area of consolidated lung we find that the voice sounds are much the same; still less intense, perhaps, but still clear. The same would be true of whispered w^ords, and of the breath sounds. The sound vibrations are in all three instancss produced at the glottis; and are transmitted either directly, hy the tissues of the neck, or downward first by the air icithin the trachea, bronchi and bronchioles, and then by the tissue of the consolidated lung, and chest wall. Although the distance which must be traversed by those vibrations passing downw^ard to the chest wall is much greater, still their inten-

PHYSICS OF AUSCULTATION OF THE LUNGS 31

sity is surprisingly well maintained. This is because of the particularly good transmission in their course within the bronchial tubes.

In ordinary cases of consolidated lung the large bronchi remain open so that the vibrations have but a relatively short distance of solid lung to traverse. Should the bronchi be closed with fibrinous exudate, however, as is the case in so-called massive pneumonia (vide p. 136), conduction through a much longer distance of solid tissue is necessary and tremendous loss of intensity results.

According to the thickness of the chest wall the intensity of the sounds is altered for the same reason — because solid tissue is not a particularly good conductor. On the other hand, the sounds may be heard unexpectedly well at the outer end of the clavicle, since bones transmit much better than soft tissue.

Transmission of Glottis-bronchial Sounds through Normal Lung. — The normal alveolar tissue of the lung offers a great obstacle to the transmission of sound waves. The vibrations must pass successively through layer after layer of alternate air and solid. Great loss of intensity through dispersion results. The sounds lose in intensity just as if they had to traverse a layer of felt.

Over normal lung the whisper sounds are practically absent — their relatively weak vibrations being completely blocked by the alveolar tissue. Voice sounds are far more intense than whisper to start with, and so are able to penetrate to the chest w^all, though modified in two respects. Voice sounds heard over normal lung are less intense and also have a muffled, humming quality, quite distinct from the clear-cut sounds heard over a consoHdated area. The latter modification is due to secondary vibrations set up in the taut-drawn elastic fibers of the alveolar walls, which blur the distinctness of the original sound waves. They may be compared to the added secondary sounds heard on speaking through a paper-covered comb, or on talking into a piano.

The breath sounds over normal lung are very different from those heard at the trachea, cervical spines, or over an area of consolidation. What these differences are will be considered in great detail later {vide p. 114). Over consolidated lung we hear the same breath sounds that we hear at the trachea, though less intense because of the distance which the vibrations, produced chiefly at the glottis, must travel in reaching the chest wall. The normal alveolar tissue, on the one hand, muffles and partially obliterates these glottis and bronchial breath sounds, just as it blocks off the sound waves of the whispered voice. On the other hand, the air entering and leaving the alveolar vesicles, and particularly the alternate stretching and relaxing of the elastic framework of those cells, produce the main sound vibrations which we hear over normal lung. In inspiration the sounds contributed by the alveoli are far more intense. The string that is being stretched is the string that complains. In vesicular breathing the greater intensity of the inspiratory sound seems

PHYSICS OF AUSCULTATION OF THE LUNGS 33

wholly of alveolar origin. In expiration, however, the sounds produced in the alveoli are much fainter, and a little of the glottis-bronchial vibrations is frequently audible, particularly when the patient breathes forcibly, or pants.

Infiltration or Partial Consolidation of the Lungs. — This gives so-called bronchovesicular breathing, because the consolidated patches, on the one hand, conduct the glottis-bronchial sounds; while on the other hand, such areas as are normal contribute vesicular sounds to the respiratory murmur which is heard.

Solid Tumor, Cyst or Abscess. — The presence of either of these in the lung modifies the breath sounds, first, by the fact that it replaces the normal lung tissue and therefore prevents the production of vesicular sounds at that point; and second, because the glottis and bronchial vibrations have just so much added solid tissue to penetrate, through which they are not conducted by open bronchioles as in ordinary consolidation. Such conditions, therefore, resemble that of massive consolidation ; and, if sufficiently large, obliterate all breath sounds.

A Superficial Cavity in the Lung. — This condition similarly abolishes the alveolar element of the breath sounds at that point. If there is close contact or free communication with the bronchus, the glottis-bronchial voice, breath sound and whisper vibrations are well transmitted; but to them are added the overtones produced by the resonator action that any such air space possesses. According to the intensity of the 3 overtones the sounds heard are called cavernous or amphoric, depending on whether they are more or less musical.

Pneumothorax. — The presence of air within the pleura usually decreases the intensity of the breath sounds because the vibrations have one additional layer to traverse. They must suffer the dispersion incidental to passage from tissue to air, and air back to tissue again, before reaching the chest wall. Also the lung upon the affected side is more or less thrown out of function by collapsing against the mediastinum, so that less air is flowing to and fro within its bronchi. Frequently that chest is motionless.

In cases where the communication between the bronchi and the pleural cavity remains widely open, however, the sounds may be intense, consisting of the glottis-bronchial vibrations, which have now no need of passing through an alveolar layer; and also of vibrations produced at the point of connection between bronchus and pleural cavity. But more important than the intensity of breath sounds is the production of overtones by the resonator action of the air space, just as occurs in pulmonary cavities; so here extreme grades of amphoric or cavernous voice and breath sounds may be met.

Pleural Effusions. — The presence of fluid within the pleural cavity modifies the signs obtained by auscultation in rather contradictory ways. As will be considered later, the fluid does not lie in a flat layer at the bottom of the chest except in cases of hydro-

PHYSICS OF AUSCULTATION OF THE LUNGS 35

pneumothorax. In simple pleural effusions the fluid, though collecting somewhat beneath the lung, rises up laterally so as to also surround the lower portion of the lung, particularly posteriorly. As we cannot examine the diaphragmatic aspect of the thorax, we are especially interested with the effect of the layer of fluid which separates the lung from the chest wall. Moderate collections of fluid, which merely relax the adjacent lung, decrease the intensity of the breath sounds simply by hindering the passage of their vibrations. Larger collections, as they compress the adjacent lung, prevent the production of the vesicular element of the breath sounds, and in proportion as they convert the lung into a solid atelectatic state, they abolish the muffling action which normal alveoli exert upon the glottis-bronchial vibrations. Lung which is merely relaxed, but by no means atelectatic, conducts sounds far better than in the distended state; as may be readily verified by listening to a watch through a layer of relaxed and then through a layer of reinflated lung. Though fluid is not a good sound conductor, it is better than distended alveolar tissue, and the glottis-bronchial element of the breath sounds, though faint, are usually audible. The less common occurrence of intense bronchial breath sounds over fluid, more difficult of explanation, is perhaps due to the fluid being in direct contact with an unusually large area of exposed bronchus at the root of the lung, or to complete atelectasis.

ADVENTITIOUS SOUNDS.

Certain physical changes in the lungs caused by disease may merely manifest themselves by alterations of intensity and quality of the respiratory murmur. In two other pathological processes we find on auscultation a new set of so-called adventitious sounds.