rising or falling of the chest-wall during respiration, various instruments have
been invented. The thoraco-meter of Sibson (Fig. 108) measures the elevation in
different parts of the sternum. It consists of two metallic bars placed at right
angles to each other; one of them, A, is placed on the vertebral column. On B
there is placed a movable transverse bar, C, which carries on its free-end a toothed
rod, Z, directed downwards. The lower end of this rod is provided with a pad
which rests on the sternum, while its toothed edge drives a small wheel which
LIMITS OF THE LUNGS.
moves an index, whose excursions are indicated on a circle with a scale attached
The Cyrtometer of
Woillez is very useful. A
brass chain, composed of
movable links, is applied in
a definite direction to part
of the chest-wall, e.g., trans-
versely on a level with the
nipple, or vertically upon
the mammillary or axillary
lines anteriorly. There are
freely movable links at two
parts which permit the chain
to be easily removed, so that
as a whole it still retains its
form. The chain is laid
upon a sheet of paper, and
a line drawn with a pencil
around its inner margin gives
the form of the thorax (Fig.
Limits of the Lungs. The extent and boundaries of the lungs are
ascertained in the living subject by means of Percussion, which consists
in lightly tapping the chest- wall by means of a hammer (percussion-
hammer). A small ivory or bony plate (pleximeter), held in the
left-hand, is laid on the chest, and the hammer is made to strike this
plate, whereby a sound is emitted, which sound varies with the con-
dition of the subjacent lung-tissue. Wherever the lung substance in
contact with the chest-wall contains air, a clear resonant tone or sound
such as is obtained by striking a vessel containing air, a clear
percussion sound is obtained. Where the lung does not contain air,
a dull sound like striking a limb is obtained. If the parts containing
air be very thin, or are only partially filled with air, the sound is
Fig, 109, along with Fig. 31, indicate the relations of the lungs to
the anterior surface of the chest. The apices of the lungs reach 3-7
centimetres (I'l 2'7 inches) above the clavicles anteriorly, while
posteriorly they extend from the spines of the scapula as high as the
seventh spinous process. The lower margin of the right lung in the
passive position (moderate expiration) of the chest, commences at the
right margin of the sternum at the insertion of the sixth rib, runs under
the right nipple, nearly parallel to the upper border of the sixth rib,
and descends a little in the axillary line, to the upper margin of the
seventh rib. On the left side (apart from the position of the heart), the
lower limit reaches as far down anteriorly as the right. In Fig. 109
the line, a, t, 6, shows the lowest limit of the passive lungs. Posteriorly,
LIMITS OF THE LUNGS.
both lungs reach as far down as the tenth rib. During the deepest
inspiration, the lungs descend anteriorly as far as between the sixth and
seventh ribs, and posteriorly to the eleventh rib whereby the
diaphragm is separated from the thoracic "wall (Fig.' 105). During the
deepest expiration, the lower margins of the lungs are elevated almost
as much as they descend during inspiration. In Fig. 109, m, n, indicates
the margin of the right lung during deep inspiration ; h, I, during deep
It is important to observe the relation of the margin of the left lung
Topography of the lungs and heart during inspiration and expiration (v. Dusch) .
A, I, upward limit of margin of lung during deepest expiration; m, n, lower
limit during deepest inspiration; t, t', t", triangular area where the heart is
uncovered by lung, dull percussion sound; d, d', d", muffled percussion
sound; i, i', anterior margin of left lung reaches this line during deep inspira-
tion, and during deep expiration it recedes as far as e, e'.
to the heart. In Fig. 109, a somewhat triangular space, reaching from
the middle of the point of insertion of the fourth rib to the sixth rib on
the left side of the sternum, is indicated. In the passive chest, the heart
lies in contact with the thoracic wall in this triangular area. This area
is represented by the triangle, t, t', t", and percussion over it gives a
dull sound (superficial dulness).
In the area of the larger triangle, d, d", d", where the heart is
244 PATHOLOGICAL VARIATIONS OP THE PERCUSSION SOUNDS.
separated from the chest-wall by the thin anterior margins of the lung,
percussion gives a muffled sound, while further outwards a clear lung
percussion sound is obtained. During deep inspiration, the inner
margin of the left lung reaches over the heart as far as the insertion
of the mediastinum, whereby the dull sound is limited to the smallest
triangle, t, i, i f . Conversely, during very complete expiration, the
margin of the lung recedes so far that the cardiac dulness embraces
the space, /, e, e.
115. Pathological Variations of the Percussion
The normal clear resonant percussion sound of the lungs becomes muffled when
infiltration takes place into the lungs, so as to diminish the normal amount of air
within them, or when the lungs are compressed from without, e.g., by effusion of
fluid into the pleura. The percussion sound becomes clearer when the chest-wall
is very thin, as in spare individuals during very deep inspiration, and especially
in emphysema, where the air-vesicles of certain parts of the lung (apices and
margins) become greatly dilated.
The pitch of the percussion sound ought also to be noted. It depends upon the
greater or less tension of the elastic pulmonary tissue, and on the elasticity of the
thoracic wall. The tension of the elastic tissue is increased during inspiration and
diminished during expiration, so that even under physiological conditions, the
pitch of the sound varies.
The sound is said to be tympanitic (Skoda) when it has a musical quality
resembling the timbre of a sound produced on a drum, and when it has a slight
variation in pitch. If a caoutchouc ball be placed near the ear, on tapping it
gently, a well-marked tympanitic sound is heard, and the sound is of higher pitch
the smaller the diameter of the ball. A tympanitic sound is always produced
on tapping the trachea in the neck. A tympanitic sound produced over the
chest is always indicative of a diseased condition. It occurs in cases of cavities
or vomicae within the substance of the lung (the sound becomes deeper when the
mouth, or, better, the mouth and nose, are closed), when air is present in one
pleural cavity, as well as in conditions where the tension of the pulmonary tissues
is diminished. The tympanitic sound resembles the metallic tinkling which is
heard in large pathological cavities in the lungs, or which occurs when the pleural
cavity contains air, and when the conditions which permit a more uniform reflec-
tion of the sound-waves within the cavity are present.
When percussing a chest, we may determine whether the substance lying under
the portion of the chest under examination presents great or small resistance to
the blow, either of the percussion-hammer or of the tips of the fingers, as the case
Phonometry. If the stem of a vibrating tuning-fork be placed on the chest -
wall over a part containing air, its sound is intensified; but if it be placed over a
portion of the lung which contains little or no air its sound is enfeebled (von
Historical. The actual discoverer of the art of percussion was Auenbrugger
(f!809). Piorry and Skoda developed the art and theory of percussion, while
Skoda originated and developed the physical theory (1839).
THE NORMAL RESPIRATORY SOUNDS. 245
116. The Normal Respiratory Sounds,
Normal Vesicular Sound. If the ear directly, or through the
medium of a stethoscope, be placed in connection with the chest-wall,
we hear over the entire area, where the lung is in contact with the
chest, the so-called "vesicular" sound, which is audible only during
inspiration. It is a fine sighing or rustling sound. It is said to be
caused by the sudden dilatation of the air-vesicles (hence " vesicular")
during inspiration, and it is also ascribed to the friction of the current
of air entering the alveoli.
The sound has, at one time, a soft, at another, a sharper character;
the latter occurs constantly in children up to 12 years of age. In
their case, the sound is sharper, because the air, in entering vesicles one-
third narrower, is subjected to greater friction. As the air passes out
of the air-vesicles during expiration, it gives rise to a feeble sighing
sound of an indistinct soft character.
Bronchial Respiration. Within the larger air-passages larynx,
trachea, bronchi during inspiration and expiration, there are loud
sounds like a sharp h or ch the " bronchial" the laryngeal, tracheal,
or " tubular" sound, or breathing. This sound is also heard between
the scapulae, at the level of the fourth dorsal vertebra (bifurcation of
trachea), and it occurs also during expiration, being slightly louder on
the right side, owing to the slightly greater calibre of the right
At all other parts of the chest, the vesicular sound obscures the
tubular or bronchial sound. If the air-vesicles are deprived of their
air, the tubular breathing becomes distinct. It is asserted that, when
lungs containing air are placed over the trachea, the tubular sound
there produced becomes vesicular. In this case, we must suppose
that the vesicular sound arises from the tubular breathing becoming
weakened, and being acoustically altered, by being conducted through
the lung alveoli (Baas, Penzoldt). A sighing sound is often produced
at the apertures of the nose and mouth during forced respiration.
117. Pathological Respiratory Sounds.
Historical. Although several abnormal sounds in connection with diseases of
the respiratory organs were known to Hippocrates (succussion-sound, friction, and
several catarrhal sounds), still, Laennec was the discoverer of the method of
auscultation (1816), while Skoda greatly extended our knowledge of its facts.
(1.) Bronchial breathing occurs over the entire area of the lung, either when
the air- vesicles are devoid of air, which may be caused by the exudation of fluid
or solid constituents, or when the lungs are compressed from without. In both
246 PATHOLOGICAL RESPIRATORY SOUNDS.
cases vesicular sounds disappear, and the condensed or solidified lung-tissue conducts
the tubular sound of the large bronchi to the surface of the chest. It also occurs
in large cavities, with resistant walls near the surface of the lung, provided these
cavities communicate with a large bronchus.
(2.) The amphoric sound is compared to that produced by blowing over the
mouth of an empty bottle. It occurs either when a cavity at least the size of
the fist exists in the lung, which is so blown into during respiration that a
peculiar amphoric-like sound with a metallic timbre is produced; or when the
lung still contains air, and is capable of expansion; as there is still air in the
pleural cavity, it acts as a resonator, and causes an amphoric sound, simultaneous
with the change of air in the lungs.
(3.) If obstruction occurs in the course of the air-passages of the lungs, various
results may accrue, according to the nature of the resistance: (a.) owing to various
causes, e.g., in the apices of the lungs there may be partial swelling of the walls
of the air-tubes, or infiltration into the air-cells which hinders the regular supply of
air. In these cases, parts of the lung are not supplied with air continuously ; it
only reaches them periodically. In these cases a cog-wheel sound occurs. A
similar sound may be heard occasionally in a normal lung, when the muscles of
the chest contract in a periodic spasmodic manner. (6. ) When the air entering
large bronchi causes the formation of bubbles in the mucus which may have
accumulated there, "mucous rales" are produced. They also occur in small
spaces when the walls are separated from their fluid contents by the air entering
during inspiration, or when the walls, being adherent to each other, are suddenly
pulled asunder. The rales are distinguished as moist (when the contents are
fluid), or as dry (when the contents are sticky); they may be inspiratory,
expiratory, or continuous, or they may be coarse or fine; further, there is the
very fine crepitation or crackling sound, and lastly, the metallic tinkling caused
in large cavities through resonance, (c.) When the mucous membrane of the
bronchi is greatly swollen, or is so covered with mucus that the air must force its
way through, deep sonorous roncTii (ronchi sonori) may occur in the large air-
passages, and clear shrill sibillant sounds (ronchi sibilantes) in the smaller ones.
When there is extensive bronchial catarrh, not unfrequently we feel the chest-
wall vibrating with the rale sounds (Bronchial fremitus).
(4. ) If fluid and air occur together in one pleural cavity in which the lung is
collapsed, on moving the person's thorax vigorously, we hear a sound such as is
produced when air and water are shaken together in a bottle. This is the
SUCCUSSION sound of Hippocrates. Much more rarely, this sound is heard under
similar conditions in large pulmonary cavities.
(5.) When the two apposed surfaces of the pleura are inflamed, have become
soft, and are covered with exudation, they move over each other during
respiration, and in doing so, give rise to FRICTION sounds, which can be felt (often
by the patient himself), and can also be heard. The sound is comparable to the
sound produced by bending new leather.
(6.) When we speak or sing in a loud tone, the walls of the chest vibrate
(PECTORAL FREMITUS), because the vibration of the vocal cords is propagated
throughout the entire bronchial ramifications. The vibration is, of course,
greatest near the trachea and large bronchi. If there be much exudation or air in
the pleura, or great accumulation of mucus in the bronchi, the pectoral fremitus
is diminished or altogether absent.
All conditions which cause bronchial breathing increase the pectoral fremitus.
Under normal circumstances, therefore, it is louder where bronchial breathing
is heard normally. The ear hears an intensified sound, which is called BRONCHO-
PHONY. If through effusion into the pleura or inflammatory processes in the lung-
tissue the bronchi are pressed flat, a peculiar bleating sound (^EGOPHONY) may be
PRESSURE IN THE AIR- PASSAGES DURING RESPIRATION. 247
118. Pressure in the Air-Passages During
Normal Respiration. If a manometer be tied into the trachea of an
animal, so that the respiration goes on completely undisturbed, during
every inspiration there is a negative pressure ( 3 mm. Hg.) and dur-
ing expiration a positive pressure (Bonders). Bonders placed the
U-shaped manometer tube in one nostril, closed his mouth, leaving
the other nostril open, and respired quietly. During every quiet
inspiration, the mercury showed a negative pressure of 1 mm., arid
during expiration a positive pressure of 2-3 mm. (Hg.)
Forced Respiration. As soon as the air was inspired or expired
with greater force, the variations in pressure became very much greater,
e.g., during speaking, singing, and coughing. The inspiratory pressure
was= 57mm. (36-74). the greatest expiratory pressure + 87 (82-100)
mm. Hg. (Bonders). The pressure of forced expiration therefore, is 30
mm. greater than the inspiratory pressure.
Resistance to Inspiration. Notwithstanding this, we must not con-
clude that the expiratory muscles act more powerfully than the inspira-
tory; for during inspiration, a variety of resistances has to be overcome,
so that after these have been met, there is only a residue of the
force for the aspiration of the mercury. The resistances to be overcome
by the inspiratory muscles are: (1.) The elastic tension of the lungs,
which during the deepest expirations = 6 mm. ; during the deepest in-
spirations = 30 mm. Hg. ( 107). (2.) The raising of the weight of the
chest. (3.) The elastic torsion of the costal cartilages. (4.) The depression
of the abdominal contents, and the elastic distension of the abdominal
walls. All these not inconsiderable resistances, which the inspiratory
muscles have to overcome, act during expiration, and aid the expiratory
muscles. The forces concerned in inspiration are decidedly much greater
than those of expiration.
As the lungs within the chest, in virtue of their elasticity, con-
.tinually strive to collapse, necessarily they must cause a negative
pressure within the chest This amounts in dogs during inspiration,
to 7*1 to 7 '5 mm. Hg., and during expiration to 4 mm. Hg. (Heynsius).
The analogous values for man have been estimated at 4*5 mm. Hg. and
3 mm. Hg., by Hutchinson.
Even the greatest inspiratory or expiratory pressure is always much less than the
blood-pressure in the large arteries; but if the pressure be calculated upon the
entire respiratory surface of the thorax, very considerable results are obtained.
Effects of the first Respiration on the Thorax. Until birth, the airless
lungs are completely collapsed (atelectic) within the chest, and fill it, so that on
opening the chest in a dead foetus, pneumo-thorax does not occur (Bernstein).
248 NASAL BREATHING.
Supposing, however, respiration to have been fully established after birth, and
air to have freely entered the lungs, if a manometer be placed in connection with
the trachea and the chest b'e opened, the manometer will register a pressure of
6 mm. Hg., due to the collapse of the elastic lungs. Bernstein supposes that the
thorax assumes a new permanent form, due to the first respiratory distension; it
is as if, owing to the respiratory elevation of the ribs, the thorax had become
permanently too large for the lungs, which are, therefore, kept permanently
distended, but collapse as soon as air passes into the pleura. When a lung has
once been filled with air, it cannot be emptied by pressure from without, as the
small bronchi are compressed before the air can pass out of the alveoli. The
expiratory muscles cannot possibly expel all the air from the lungs, while the
inspiratory muscular force is sufficient to distend the lungs beyond their elastic
equilibrium. Inspiration distends the lungs, increasing their elastic tension, while
expiration diminishes the tension without abolishing it.
119. Appendix to Respiration.
Nasal Breathing. During quiet respiration, we usually breathe
or ought to breathe through the nostrils, the mouth being closed.
The current of air passes through the pharyngo-nasal cavity so that
in its course during inspiration, it is (1) warmed and rendered moist, and
thus irritation of the mucous membrane of the air-passages by the cold
air is prevented ; (2) small particles of soot, or other foreign substances
in the air, adhere to, and become embedded in the mucus covering the
somewhat tortuous walls of the respiratory passages, and are carried
outwards by the agency of the ciliated epithelium of the respiratory
passages ; (3) disagreeable odours and certain impurities are detected by
the sense of smell.
If a lung be inflated, air constantly passes through the walls of the alveoli and
trachea. This also occurs during violent expiratory efforts (cutaneous emphysema
in whooping-cough), so that pneumo-thorax may occur (J. R. Ewald and
Pulmonary (Edema, or the exudation of lymph or serum into the pulmonary
alveoli, occurs: (1) When there is very great resistance to the blood-stream in
the aorta or its branches, e.g., by ligaturing all the arteries going to the head
(Sig. Mayer), or the arch of the aorta, so that only one carotid remains pervious
(Welch). (2) When the pulmonary veins are occluded. (3) When the left
ventricle, owing to mechanical injury, ceases to beat, while the right ventricle
goes on contracting (p. 75). These conditions produce at the same time anaemia
of the vaso -motor centre, which results in stimulation of that centre, and conse-
quent contraction of all the small arteries. Thus, the blood-stream through the
veins to the right heart is favoured, and this in its turn favours the production of
redema of the lungs.
120. Peculiarly Modified Respiratory Movements.
(1.) Coughing. Consists in a sudden violent expiratory explosion after a
previous deep inspiration and closure of the glottis, whereby the glottis is forced
open and any substance, fluid, gaseous or solid, in contact with the respiratory
mucous membrane is violently ejected through the open mouth. It is produced
PECULIARLY MODIFIED RESPIRATORY MOVEMENTS. 249
voluntarily or reflexly; in the latter case, it can be controlled by the will only to
a limited extent.
[Causes. A cough may be discharged rcjlexly from a large number of surfaces.
(1) A draught of cold air striking the skin, especially of the upper part of the
body. (2) More frequently it is discharged from the respiratory mucous mem-
brane, especially of the larynx, the sensory branches of the vagus and the superior
laryngeal nerve being the afferent nerves. (3) Sometimes an offending body, such
as a pea in the external auditory meatus gives rise to coughing, the afferent nerve
being the auricular branch of the vagus. (4) There seems to be no doubt that
there may be a "gastric cough," especially in cases of indigestion, produced by
stimulation of the gastric branches of the vagus.]
(2.) Hawking, or clearing the throat. An expiratory current is forced in a
continuous stream through the narrow space between the root of the tongue and
the depressed soft palate, in order to assist in the removal of foreign bodies.
When the act is carried out periodically the closed glottis is suddenly forced open,
and it is comparable to a voluntary gentle cough. This act can only be produced
(3.) Sneezing consists in a sudden violent expiratory blast through the nose,
for the removal of mucus or foreign bodies (the mouth being rarely open) after a
simple or repeated spasm-like inspiration the glottis remaining open. It is
usually caused reflexly by stimulation of sensory nerve-fibres of the nose [nasal
branch of the fifth nerve], or by sudden exposure to a bright light (Cassius
Felix, A.D. 97) [the afferent nerve is the optic]. This reflex act may be interfered
with to a certain extent, or even prevented, by stimulation of sensory nerves,
firmly compressing the nose where the nasal nerve issues. The continued use of
sternutatories, as in persons who take snuff, dulls the sensory nerves, so that they
no longer act when stimulated reflexly.
(4.) Snoring occurs during respiration through the open mouth, whereby the
inspiratory and expiratory stream of air throws the uvula and soft palate into
vibration. It is involuntary, and usually occurs during sleep, but it may be
(5.) Gargling consists in the- slow passage of the expiratory air-current in the
form -of bubbles through a fluid lying between the tongue and the soft palate,"
when the head is held backwards. It is a voluntary act.
(6.) Crying, caused by emotional conditions, consists in short, deep
inspirations, long expirations with the glottis narrowed, relaxed facial and jaw
muscles, secretion of tears, often combined with plaintive inarticulate expressions.
When crying is long continued, sudden and spasmodic involuntary contractions
of the diaphragm occur, which cause the inspiratory sounds in the pharynx and
larynx known as sobbing. This is an involuntary act.
(7.) Sighing is a prolonged inspiration, usually combined with a plaintive
sound often caused involuntarily, owing to painful or unpleasant recollections.
(8.) Laughing is due to short, rapid expiratory blasts through the tense vocal
cords which cause a clear tone, and there are characteristic inarticulate sounds in
the larynx, with vibrations of the soft palate. The mouth is usually open, and
the countenance has a characteristic expression, owing to the action of the M.
zygomaticus major. It is usually involuntary, and can only be suppressed, to a
certain degree, by the will (by forcibly closing the mouth and stopping respiration).
(9.) Yawning is a prolonged, deep inspiration occurring after successive
attempts at numerous inspirations the mouth, fauces, and glottis being wide
open ; expiration shorter both acts often accompanied by prolonged character-
istic sounds. It is quite involuntary, and is usually excited by drowsiness or