THE THORAX
We have already had occasion to point out, in connection with the
_types of stature_, the importance of the thorax.
The relation of the thoracic perimeter (circumference of the chest) to
the total stature (see chapter on _Technique_) was called by Goldstein
the _index of life_, in order to indicate that the organic resistance
of any individual depends upon the proportional relation between the
thorax and the whole body; whoever has a narrow chest is liable to
pulmonary tuberculosis, and in his physiological entirety is a weakling
(see chapter on _Macroscelous and Brachyscelous_ _Types_).
_Anatomical Parts._--Anatomically the thorax is determined in height
by the twelve dorsal or thoracic vertebrae, which are characterised by
having a transverse apophysis, which articulates with the twelve pairs
of ribs, forming the _thoracic cage_, or chest.
The first seven pairs of ribs articulate in front, by means of
cartilages, with the lateral margins of a flat bone, the sternum
or breast-bone, which is formed of three pieces: the _manubrium_
uppermost, then the _corpus_, then, lowest of all, the _ensiform_
(sword-shaped) _process_.
The manubrium and the corpus form, at their juncture, an angle more or
less marked, according to the individual, and the lateral articulation
of the second rib corresponds to this angle. In the new-born child
the sternum is a cartilage with points of ossification arranged
longitudinally like the beads of a rosary. The seventh vertebra
articulates laterally at the point at which the ensiform process is
attached to the corpus of the sternum. The next three ribs (8th, 9th
and 10th) are articulated together and with the seventh by means of
cartilaginous arches; the last two pairs of ribs (11th and 12th) are
free or _floating_. At the top, the thoracic cage is reinforced by the
_thoracic girdle_, which serves also to afford articulation for the
upper limbs, and which consists of the _clavicles_, in front, and of
the scapulae, behind. The clavicles are long bones placed in an almost
horizontal position above the thorax, and they determine the _width_ of
the chest; at the inner extremity they articulate with the manubrium
of the sternum and at the outer extremity they are attached to the
acromial process of the scapulae. The scapulae are flat bones which are
attached to the posterior surface of the thoracic frame, on which they
are freely movable, covering a tract extending from the second to the
seventh rib. At their upper and outer extremity they are provided
with two bony processes; namely, the _acromion_, already mentioned,
which contains the points of maximum width of the shoulders, and the
_coracoid process_, which terminates anteriorly and, together with the
acromion, overhangs the articulation of the humerus with the body of
the scapula.
Powerful muscles clothe the thoracic frame, serving partly in
the movements of respiration and partly in the movements of the
upper limbs. It may suffice to mention, among the muscles situated
posteriorly, the _cucullaris_, the great dorsal (_m. longissimus_
_dorsi_), the rhomboids of the scapulae (_m. rhomboideus major_ and
_minor_), and the _serratus posterior_ of the ribs; anteriorly, the
large and small pectoral and the great _serratus_; beside which there
are the intercostal muscles, extending from rib to rib and taking part
in the movements of respiration. But the most important muscle is
the _diaphragm_, which completely closes the thoracic cavity, rising
into it in a convex vault and separating it from the abdomen; this
constitutes the most active of all the muscles which participate in
the movements of respiration. The thoracic cavity, thus determined,
encloses the two most important viscera of vegetative life--the heart
and the lungs.
The heart is a muscle shaped like a pear or cone, having its base
turned upward, and its apex or point turned downward and outward
toward the left, corresponding to the fifth intercostal space; it is
divided, as is well known, into four cavities, and constitutes the
_great motor power_ of the circulation of the blood. The lungs are
two in number, right and left, and surround the heart, completely
filling the thoracic cavity. The lungs are divided into superimposed
_lobes_, three in the right and two in the left lung; they are composed
essentially of infinitely small ramifications of the bronchi, resolving
into tiny series of chambers, the _pulmonary alveoli_ or air-cells.
These alveoli, consisting of a single layer of extremely small cells,
are surrounded by a dense network of capillary tubes, through which
takes place the interchange of oxygen and carbon dioxide. It has been
calculated that if we should estimate and sum up the internal surfaces
of the pulmonary alveoli, or, what comes to the same thing, if we
should spread out and join together the alveolar walls of the lungs,
they would have a superficial area of 200 square metres. This area
might be compared to the foliage of a great human tree (respiratory
surface).
_Physiological and Hygienic Aspect._--The importance of the thorax
is physiological, because it contains the highly important viscera
of vegetative life; but this importance is especially associated
with the lungs. The lungs are the organs that acquire the oxygen
from the outside environment, and this oxygen, when taken up by the
hemoglobin in the blood, will serve to oxygenate the tissues of the
entire organism, and thus aid in the processes of cellular metabolism.
A large supply of oxygen stimulates this interchange of matter, not
only because the organism as a whole is enriched in the substance
essential to this process (oxygen), but because the heart responds
to the increased activity of the lungs by more energetic pulsations
calculated to set the blood circulating in far greater quantities. It
is no exaggeration to say that our whole physiological life is enclosed
within the thorax, because the digestive system does nothing more
than prepare a blood that is unfitted to irrigate the tissues for the
purpose of supplying them with nutriment; it is only after this blood
has passed through the lungs that it is transformed into _oxygenated
blood_ and is adapted to assimilation. Consequently the intestines
prepare nothing more than the _raw material_, and it is the lungs which
perform the service of perfecting it; while the heart drives it through
its circuit into contact with all the tissues of the organism.
Whoever has inadequate lungs is for that reason alone a person who
necessarily receives insufficient nutriment (thin and weak macroscele),
and frequently is also a melancholiac. Melancholia accompanies every
form of physiological decadence. On the contrary, persons with ample
lungs are generally serene of spirit and joyous. In fact, the emotion
of joy is at the same time both the cause and the consequence of an
active circulation of oxygenated blood (florid or ruddy complexion).
Certain experiments conducted with birds have proved that if free
oxygen is introduced under an air-bell in which the birds have been
enclosed, they gradually become more and more excited, singing and
fluttering as if possessed by a frenzy of joyousness. It is a fact
that we often rid ourselves of a fit of melancholy by taking a walk in
the open air; persons possessed of good lungs feel within themselves
a vital potentiality that perceptibly aids them to make what we call
an "effort of will"; when sorrow befalls them, or overexertion has
exhausted their strength, persons of this type feel some force spring
up within them that seems to give them fresh hope and courage. It is
their oxygenated blood, which neither weariness nor depression of
spirit can stay in its luxuriant course; the man of weak lungs, on
the contrary, is mentally depressed, because his physiological life
has slowed down; and, instead of aiding him, it is his physiological
life which demands of him a genuine effort of will to reestablish its
equilibrium.
Accordingly, those persons who have a well-developed chest are
certainly the healthiest and the happiest.
But this is not the only pulmonary function; the lungs are also the
_organs of speech_. In fact, while speech is manufactured in the brain
and the cerebral nerves that stimulate the organs of the spoken word,
it requires also its "driving power," that is to say, air, in order to
obtain utterance; and it is the lungs to which singers and speakers
alike owe the physical strength of their voice. Even the respiratory
rhythm has a great influence upon speech.
The spoken word requires a most complicated mechanism, and among the
details of this mechanism, by no means the least important are the
acts of _inspiration_, by which the air is received into the lungs,
and of _expiration_, by which it is expelled, simultaneously with all
the other movements producing speech. Indeed, we know that when speech
is further complicated by the act of singing, it becomes necessary to
_study special rules_ for breathing; in short, to _educate the voice_.
Now, why do we not also educate the voice for its ordinary task of the
spoken language? Speech is one of the marvels that characterise man,
and also one of the most difficult spontaneous creations that have
been accomplished by nature. Through the voice, the lawyer defends the
innocent, the teacher educates the new generations, the mother recalls
her erring son to the path of virtue, lovers unite their souls, and all
humanity interchanges ideas. If intelligence is the triumph of life,
the spoken word is the marvellous means by which this intelligence is
manifested.
We trouble ourselves to educate the voice only for the purpose of
singing, and neglect the spoken word. We do not stop to think that
_singing_ appeals only to the senses and emotions, while speech appeals
to the emotions and the intellect, and therefore charms and at the same
time convinces.
Anyone who has heard that wonderfully gifted speaker, Ofelia Mazzoni,
expounding our great poets to the labouring classes at the People's
University in Milan, rousing the slumbering intelligence of the working
man, will understand what an immense educative force we are neglecting.
In a century in which we speak of an intellectual reawakening and a
brotherhood of man, we have forgotten the _voice_! Yet in this new era
of humanity that is learning brotherly love and striving for peace,
the voice plays a part analogous to that of the trumpet-call in the
centuries consecrated to war.
As a matter of fact, our schools so far neglect defects of speech that
it is not uncommon to hear a stammerer undergoing examinations for a
degree in jurisprudence. The fact that an otherwise cultured man lisps
or stammers is treated by us as quite an indifferent matter, just
as among savage tribes a king may have unclean nails without anyone
observing the fact.
Yet it is now known that stammering may usually be cured by a
systematic training in the art of breathing.
Respiratory gymnastics ought to constitute one of the principal courses
of instruction in schools for children. I have introduced it into the
"Children's Houses," among children between the ages of four and six,
combining it with a special instruction in written language (letters of
the alphabet), designed to _educate_ _the movements_ of the organs of
speech, without worrying or tiring the children, and this method has
borne such good results that our little ones, by the time they are five
years old, have lost nearly all their defects in pronunciation.
=Spirometry.=--The _pulmonary capacity_ may be measured directly by
means of an instrument called the _spirometer_; the breath must be
strongly expelled through a tube opening into a hollow cylinder, thus
raising a graduated piston contained in it; and, by reading the figure
indicated on the piston-rod, we learn the volume of air expelled from
the lungs.
Such an instrument is better adapted for use by adults than by
children; and if it should ever come to be introduced into the
schools, it should not in any case be used below the elementary grades.
The person who is going to measure the capacity of his lungs by means
of the spirometer, begins by drawing in an unusually deep or _forced
inhalation_; then, after holding his breath for a moment, he proceeds
to expel into the rubber tube all the air in his lungs, in a _forced
exhalation_. In an exercise of this sort, all the difficulties of
respiratory gymnastics are successively surmounted--inspiration,
respiratory pause, expiration.
In fact, in accomplishing the _forced inspiration_, all the pulmonary
alveoli must be dilated to the maximum extent, and at the same time
the thorax must reach its _maximum dilation_. This is a very different
matter from normal inspiration, which does not completely dilate the
alveoli. As a matter of fact, the _tidal air_ or _air of respiration_,
_i.e._, the air taken in and expelled in each normal respiration,
is about 500 cubic centimetres; but the sum total of air habitually
contained in the lungs is made up of two quantities: first, that which
may be emitted by a _forced expiration_, the _supplemental_ _or reserve
air_, amounting to 1,600 cubic centimetres; and secondly, the air which
cannot ever be emitted, because no amount of effort could completely
expel all the air from the lungs; _residual air_ or _respiratory
residuum_ amounting to 1,200 cubic centimetres. To recapitulate,
the average pulmonary capacity is the sum of the following average
quantities of air:
_Residual air, or respiratory residuum_
(which can never be expelled from the lungs) = 1200 cu. cm.
Respiratory reserve
(which can be expelled by a forced expiration) = 1600 cu. cm.
Tidal air = 500 cu. cm.
Complementary air
(which can be drawn in by a forced inspiration) = 1670 cu. cm.
Accordingly, the total pulmonary capacity is about 5,000 cubic
centimetres, or five litres. But in normal respiration, the capacity is
less, _i.e._, about 3,300 cubic centimetres, the air due to a forced
inspiration not being included.
Therefore, in each normal respiration a half litre of pure air
(assuming that it is pure) is introduced and mingled with the vitiated
air already within the lungs; and since, in expiration, a third only
of this 500 cubic centimetres is eliminated, it follows that 166 cubic
centimetres are mingled with the 3,300 cubic centimetres; in other
words, that only one-tenth of the air is renewed in each _normal_ act
of respiration.
A very energetic forced _inspiration_ may draw into the lungs, in
addition to the customary 500 cubic centimetres, an additional 1,670
cubic centimetres of pure air, _complementary air_. In this case the
lungs contain upward of 5,000 cubic centimetres of air.
The _forced expiration_ which follows upon this extra deep inhalation
_purges_ the lungs of the vitiated air which has formed there. In this
way we complete an exercise that is eminently hygienic.
Now, these spirometric movements are fraught with difficulties: 1. The
forced inspiration, deep enough to extend the alveoli, may be more or
less complete. If a cloth wrung out in cold water is laid across the
shoulders, the _inspiration_ which follows as a result of reflex action
is far deeper than that produced by an act of will; this proves that
the lungs can be dilated to a point beyond that which seems to us to be
the extreme limit, and therefore that _with_ _practice_ we may learn to
dilate our lungs still further.
2. When the attempt is made to _hold the breath_ after a forced
inspiration, almost everyone at the first trials will allow more or
less of the air to escape; that is, they will discover themselves
incapable of controlling their own organs of respiration; therefore,
a gymnastic exercise for acquiring such control is necessary. This is
the exercise which will make us masters of the movements required to
produce vocal sounds at pleasure.
3. A slow expiration so controlled as to give time for the air to
penetrate into the spirometer, is accomplished, though somewhat
unevenly, the first few times, and is perfected with practice.
It results from the above that: 1. We take in less air than we are
able to take in; 2. part of this air is lost outside the spirometer;
consequently the spirometer registers a pulmonary capacity below that
which the lungs actually have; and we shall find that, with _practice_,
the volumetric figure will successively augment. But the pulmonary
capacity has not augmented in proportion; it is only that _practice
has perfected_ the respiratory movements. Accordingly, the spirometer
may serve as an instrument to test the progress made in respiratory
gymnastics, and, in the case of those who have already become _skilful
in its use_, it becomes a really valuable instrument for measuring the
respiratory capacity.
When we remember that a portion of the air, _i.e._, 1,200 cubic
centimetres, never issues from the lungs, it follows that the
_respiratory_ _capacity_ is less by 1,200 cubic centimetres than the
_pulmonary_ _capacity_, which, as we have seen, is on an average
upward of 5,000 cubic centimetres (5,370) in the adult man. Hence,
the spirometer directly measures the _respiratory capacity_, and only
indirectly the pulmonary capacity.
When women measure their lungs by means of the spirometer, they have
difficulty in registering 2,000 cubic centimetres, and men have
difficulty in attaining 2,600 cubic centimetres. Instead of which,
a man ought to be able to register between 3,800 and 4,000 cubic
centimetres.
What keeps the lungs healthy is an abundant aeration with air rich
in oxygen, and not impure with carbon dioxide and other poisonous
gases. When the pulmonary air-cells are insufficiently dilated, they
are predisposed to attack by the bacillus of tuberculosis. Indeed,
pulmonary tuberculosis usually begins at the _apexes of the lungs_,
which are less thoroughly aerated, and also usually attacks persons
with narrow chests. The _treatment_ of tuberculosis is eminently a
_fresh-air treatment_; tuberculous patients may be benefited and even
cured in a remarkable percentage of cases (50 per cent.) if they are
exposed day and night to the open air. In this way the relation between
free respiration and pulmonary health is demonstrated.
In America at the present time the hygienic rule of sleeping at night,
winter and summer, with the windows open, is gaining ground, and even
the practice of sleeping in the open air. And the various forms of
_sport_ also have the beneficial effect of bringing those who indulge
in them into a healthy contact with fresh air, which civilised man has
shown a fatal tendency to abandon.
The same exercise which dilates the lungs (the contents) also dilates
the thorax (the container). The result is that man ends by acquiring
the thorax corresponding to his vocation, or in other words, a thorax
corresponding to the life that he leads in consequence of the form of
work to which he devotes himself. Shepherds in mountain districts and
mountain peasants have the largest thorax, notwithstanding, as we have
seen, that they are more scantily nourished. In cities, the maximum
average circumference of chest is found among the cart-drivers, and
the minimum among university students and in general among those who
have grown up in an inclosed environment, with the thorax artificially
cramped by the position assumed while writing or reading at a desk; yet
this is the class of persons who have abundant nutriment.
Consequently, we find a division of air and bread between different
social castes; those who have air, do not have bread, and they possess
large lungs, out of proportion to bodies which, being underfed, have
been unable to grow; and those who have bread do not have air, and
they possess lungs that are insufficient for the needs of bodies that
have grown under the influence of abundant nutrition. Consequently,
all civilised men are physiologically out of equilibrium, and their
physical health is lessened. But those who suffer most from this loss
of equilibrium are the _studious_ class, who have nourished themselves
upon hopes and opened their minds to great ideas, and deluded
themselves into undertaking big enterprises; but in real action they
find that they are weak, and that they easily fall into discouragement
and depression, and when their will-power forces them onward, their
organism responds with nervous prostration and melancholia.
It is a sad fact that at the present day the best energies of man reach
maturity possessed of insufficient lungs, and consequently liable to
break down in health, energy and strength.
A large part of the _studious_ class, such, for instance, as the
teachers, are at the present day devoting themselves to a form of work
which is not a pulmonary exercise, but pulmonary _destruction_.
We must remember that healthy exercise of the lungs should take
place in the open air, and consists of indrawn breaths deep enough
to _dilate_ the air-chambers. Instead of this, the teacher _speaks_,
which means that he makes _forced expirations_, during many hours in an
enclosed environment and in an assemblage of persons who, for the most
part, are far from clean. The bacillus of tuberculosis finds in the
teacher its favourite camping-ground. In fact, statistics indicate that
the maximum mortality from tuberculosis is among teachers; higher even
than among nurses. It is really distressing to think of the ignorance
of hygiene in which our schools are even yet steeped, so that they
seem forgetful of the body, in their pursuit of a spirit that eludes
them and that, as a matter of fact, is not being educated in anything
approaching a rational manner.
When we enter a class-room, we see rows of benches constructed like
orthopedic machines, to the end that the vertical columns of the pupils
shall not be distorted during their enforced labour; and the thought
arises: this is the spot in which the teacher becomes a consumptive
for the sake of transforming the children into hunchbacks. What is
the reward of so great a sacrifice? What sort of a preparation in
ideals and in character are they giving to the new generations through
such disastrous means? What are the obstacles which they are being
taught, through so much suffering, to surmount and to conquer? What,
in short, is the spiritual gain achieved at the cost of so great an
impoverishment of the body?
The answering silence that greets these questions indicates that we
have a great mission to accomplish.
Anthropological studies made upon pupils have demonstrated that
school-children rarely attain a sufficient chest development. I
also have made my modest contribution, proving that the brightest
scholars, the prize-winners, etc., who, as a general rule, also enjoy
an advantage in social position, have a _narrower chest measure_.
Among the children that are recognised as the brightest in their
classes, I have been able to distinguish two categories: those who are
exceptionally intelligent, and those who are exceptionally studious;
the former have a better chest development than the latter.
Signorina Massa, one of my pupils at the University, in the course of
kindred studies made among pupils of a uniform social grade (the poorer
classes) observed that the _best_ and _brightest_ scholars, etc., have
a chest circumference and a muscular strength notably inferior to the
children who are not studious. There can be no doubt that an assiduous
application to the study table impoverishes the organism and above all
impedes the normal development of the thorax. This fact has a really
overwhelming importance. Study the tables of mortality in Italy for
infective diseases, _i.e._, those diseases in which mankind meets the
assault of the microscopic invader either with a strong constitution,
or with one already predisposed to defeat. The most dreaded diseases,
such as diphtheria, typhoid, measles and scarlet fever are all grouped
together under a mortality oscillating between five and twenty-five
thousand deaths a year. But bronchitis and pneumonia each cause a
mortality that ascends to between seventy and eighty thousand deaths;
in this group it is evident that we must take into consideration, not
only the infected environment, but also the organic predisposition.
Every man and woman has been prepared, by their years in school, to
have in the form of a narrow chest and an insufficient development of
the organs of respiration, a _locus minoris resistentiae_. Whoever talks
of the _war against tuberculosis_ ought first of all to investigate the
school and its pedagogic methods.
=Anthropological Aspect.= _Growth of the Thorax._--In the course of its
growth the thorax undergoes an evolution, not only in itself, but also
in its relation to the vertebral column.
[Illustration: FIG. 124.]
The nature of the transformations undergone by the skeleton of the
trunk in relation to its different parts is substantially as follows:
in the child at birth the vertebral column is straight, and the thorax
is higher up than in the adult; the pelvis, on the contrary, slants
forward and downward. In the adult the vertebral column is curved in
the form of an S, showing the two-familiar dorsal-lumbar curves, and
the axes of the thorax and pelvis are more perceptibly horizontal; in
short, in the course of growth a _descent of the thorax_ has taken
place, together with a _rotation_ of the pelvis (Fig. 124).
A. _Descent of the Thorax._--This is the chief of these
characteristics: the thorax descends in the course of its growth.
In the new-born child the upper edge of the manubrium of the sternum
is in juxtaposition to the body of the first dorsal vertebra, while in
the adult it is situated on a level with the lower edge of the second
vertebra.
Even the tendinous arch of the diaphragm has shifted, being lowered by
the space of a vertebra; it is situated between the eighth and ninth
vertebrae in the child at birth, and between the ninth and tenth in the
adult.
The outside characteristics are in correspondence with this fact; the
shoulders descend in the course of growth. In the adult, the acromia or
points of the shoulders are on a lower level than the incisura or cleft
in the sternum (which is visible at the anterior base of the neck, and
may be felt as an indented half-moon); while in the new-born child, on
the contrary, the shoulders are higher up than the upper extremity of
the sternum.
Another external characteristic of the descent of the thorax is the
change in position of the nipples at successive ages; the mammary
papillae of the adult correspond to the level of the lower extremity of
the sternum, and are situated respectively at the central points of the
two halves of the thorax; in the new-born child, on the contrary, the
mammary papillae are further apart and higher up.
[Illustration: FIG. 125.--A = vertex of triangle; B B' = extremities of
base, corresponding to the two nipples.]
These characteristics of the _descent_ of the thorax are fully
established in the period of puberty and are of great importance,
since, if not completed, they indicate cases of arrest of development
or _infantilism_.
Quetelet has made a study of the _triangulation_ of the thorax (Fig.
125).
If the two nipples and the sternal incisura are connected by straight
lines inclosing an isosceles triangle _ABB'_, the length of the base in
the new-born child is 70 millimetres, and that of the sides _BA_, _B'A_
is 54 millimetres, and the height 41 millimetres.
In the adult the dimensions are as follows: _BB'_ = 197 millimetres;
_AB_, _AB'_= 184 millimetres; and the height = 155 millimetres.
Comparing the measurements of the child at birth with those of the
adult, we find that the base in the adult is 2.81 times, and the
side 3.41 times that of the child; in other words, the sides of the
triangle increase far more than the base, and its height in the adult
(representing very nearly the entire height of the sternum), is 3.78
times that in the new-born child. Consequently, in the course of its
transformation the thorax not only descends, but it is also lengthened
in the adult, as compared with the form that it had at birth.
B. _Dimensions of Thorax in Relation to Stature._--Besides its
_descent_, there is a second transformation of the thorax, in regard
to its volumetric relations to the rest of the body. The perimeter of
the thorax and the circumference of the head are pretty nearly equal
in the new-born child; if anything, the circumference of the thorax is
a _trifle less_ than that of the head; but when it equals it, this is
a sign of _robustness_. In the majority of cases it is not until the
second year or thereabouts that the two circumferences become equal.
If, however, such inequality should still persist after the child had
entered upon the third year, it would constitute a sign of _rickets_
(head too large, chest too narrow).
As to the relations between the thoracic circumference and the stature,
it is found that in the child at birth the thoracic circumference
exceeds one-half the stature by about 10 centimetres. If the difference
is less than 8 centimetres it is a sign of feeble constitution, if it
is greater than 10 (for instance, 11 centimetres) it is a sign of great
robustness.
This difference disappears little by little; at the age of five years
it is already reduced to between 4 and 5 centimetres; at the age of
fifteen, the period of puberty, it has wholly disappeared, and the
well-known relation between the stature and the circumference of the
thorax has become established; the thoracic circumference is equal to
one-half the stature (see chapter on _Form_), and this constitutes
Goldstein's _vital index_:
_Vi_ = (100x_Tc_)/(_S_)
As early as 1895, Pagliani published some studies of children, which
reveal the _physiological_ importance of the dimensions of the thorax;
watching the lives of infants whose measurements he took at the
foundling asylum, he observed that the _mortality_ of infants is quite
rare when they exceed the above proportions between circumference of
chest, head, and stature.
From a study of 452 infants, Fraebelius has drawn the following
conclusions:
I. Mortality 21 per cent.; circumference of thorax greater than half
the stature by 9.10 centimetres; circumference of thorax less by 1.5
centimetres than perimeter of cranium.
II. Mortality 42.9 per cent.; circumference of thorax greater by 7
centimetres than one-half the stature; circumference of thorax less by
2.8 centimetres than circumference of cranium.
III. Mortality 67.5 per cent.; circumference of thorax greater by 4.5
centimetres than one-half the stature; circumference of thorax less by
4.7 centimetres than the cranial circumference.
The thorax in children of five years and upward ought to be larger by a
few centimetres (not more than from 4 to 5) than one-half the stature.
_C. Transformations of the Thorax Considered by Itself: Alterations_
_in Shape._
_Thoracic Index._--Lastly, the thorax changes its shape in the course
of growth. In the new-born child it is very prominent in front,
and narrow laterally; in the adult, on the contrary, it is more
flattened in its antero-posterior dimension and wider transversely.
Consequently the transformation consists in a notable difference in the
proportion between the width and depth of the chest, that is, between
the antero-posterior and the transverse diameters (see chapter on
_Technique_). This proportion constitutes the _thoracic_ _index_, which
is expressed by the following formula:
_Ti_ = (100A-_PD_)/_TD_
and this formula gives an idea of the _shape_ of the thorax.
In the child at birth the antero-posterior diameter is very nearly
equal to the transverse; accordingly, the index, at birth, oscillates
between 90 and 100.
In the adult, however, the thoracic index is on an average 75;
the transverse diameter therefore increases much more than the
antero-posterior diameter. According to Quetelet, while the transverse
diameter multiplies threefold in the course of its growth, the
antero-posterior merely doubles (2.36); in addition to this the thorax
also lengthens, as we have already seen.
_Proportion, Shape and Dimensions of the Thorax._--In the adult normal
man we find the following proportions: The distance between the mammary
papillae is about equal to the antero-posterior diameter of the thorax
(hence the papillae indicate the depth of chest) and is also perceptibly
equal to one-half the breadth of the shoulders (measured between the
two acromia), which, by the way, is the maximum transverse dimension of
the skeleton.
This maximum dimension (the biacromial distance) may be regarded as an
index of the skeletal development; and Godin takes its proportion to
the _transverse thoracic diameter_ (the horizontal distance between
the two vertical lines drawn from the arm-pits, in the plane of the
mammary papillae, see Chapter VII, _Technique_) in order to estimate
the proportional relation between the skeleton and the organs of
respiration. Since in the course of growth the thorax _broadens_, that
is, the transverse diameter increases more than the antero-posterior,
we should expect to find that in the course of evolution, the
difference between the transverse development of the skeleton and the
lateral development of the thorax steadily diminishes.
It happens, on the contrary, that from the age of ten years onward,
during the whole puberal development, the transverse diameter of
the thorax steadily becomes less, as compared with the breadth of
the shoulders, so much so that if the difference was at first 97
millimetres, it becomes finally 116 millimetres. According to Godin,
this indicates that the thorax does not obey the harmonic laws of the
development of the skeleton as a whole, but that, owing to causes
of adaptation (the school!) it remains definitely inferior to the
development which it might have attained, and consequently results in
throwing the organism _out of its physiological equilibrium_. In fact,
if we make men raise their arms, especially men of the student class,
a certain hollowness, which is aesthetically displeasing, is revealed
along the sides of the thorax. This deficiency is corroborated,
according to Godin's studies, by his observation of another
correspondence in the measurements of the thorax. In addition to the
customary measurements, Godin introduced, besides the well-known and
classic _thoracic perimeter_--which is the circumference taken in the
horizontal plane passing through the nipples--two other circumferences:
one of them higher up, the _subaxillary circumference_, which includes
a large proportion of the pectoral and dorsal muscles; and the other
lower down, the _submammary circumference_, which determines solely the
measurement of the thoracic skeleton, since the intercostal muscles
are practically the only ones which descend to this level. These two
circumferences are to be considered together, according to Godin, as
expressing the relation between the organs of respiration and the
muscular mass. In complete repose, the subaxillary circumference
is much greater than the submammary; but at the moment of _maximum
inspiration_ the latter should become equal to the former; hence, the
difference between the submammary circumference in repose and during
inspiration furnishes an indirect index of the _respiratory capacity_,
and the subaxillary circumference is a test of individual capacity.
Godin notes that inspiration _almost never_ succeeds in attaining an
equality between the two circumferences.
_Shape of the Thorax._--In regard to the shape, which stands in
relation to the _thoracic index_, it is found to vary according to
individual _types_; in fact the index itself, although showing a mean
average of 75, oscillates between the extremes of 65 and 85. As a
general rule, the brachycephalic races have a deeper thorax, _i.e._,
having a cross-section of more rounded form; the dolichocephalics, on
the contrary, have a more flattened thorax in the antero-posterior
direction (these races, such as the negroes, are more predisposed
to contract pulmonary tuberculosis). Consequently there is a
correspondence in _type_ between the head and the thorax. In the
measurements taken by me among the women of Latium the results show
that the brachycephalics had an average depth of thorax amounting to
188 millimetres and the dolichocephalics only 181 millimetres, while
the transverse diameters were very nearly equal: 241 millimetres in the
brachycephalics, and 240 millimetres in the dolichocephalics. Hence,
the resultant thoracic index of 78 for the brachycephalics and 75 for
the dolichocephalics.
Such differences in the index indicate also differences in the
formation of the thorax: that it is more or less flattened in the
dolichocephalics, and more prominent in the brachycephalics. There is
a corresponding diversity of form in the breasts of the women: the
dolichocephalic races have more elongated breasts (pear-shaped), the
brachycephalics more rounded.
The shape of the thoracic section is at the present time taken into
careful consideration, especially in medicine, because it is apt to
reveal predispositions to diseases.
It may be obtained by the aid of the cyrtometer (see chapter on
_Technique_). At the present day, however, exceedingly complicated
instruments have been constructed, which, by the aid of recording
indexes, give a direct representation of the shape of the thoracic
perimeter, together with its modifications and respiratory oscillations.
Since these instruments are, for the present, very far removed from
widespread practical use, we may adopt as an excellent method for
determining the shape and, at the same time, the dimensions of the
thorax, that of Maurel, in his research regarding "the square surface
of the thoracic section."
Having determined the anthropometric points, Maurel passes strips of
metal (stiff enough to retain the shape given them) around the thorax,
after the fashion of a tape-measure, first around one half, and then
around the other.
Next he places these metal strips (_still retaining the shape given_
_them_ by contact with the thorax), upon a sheet of especially prepared
paper, marked in squares, and traces upon it the _inner outline_ _of
the strips_.
The two halves must be made to coincide in such a manner as to
reproduce faithfully the thoracic section, both in form and in
dimension.
By adding up the squares contained within the outline we obtain the
area of the section.
[Illustration: FIG. 126.]
This method is the only really rational method for studying the thorax;
and its simplicity, practicality and graphic representation recommend
it as a valuable aid to pedagogic anthropology.
There is, for example, an abnormal form of thorax, which I have very
often met with in deficient children. It consists in an exaggerated
curve of the posterior costal arches, which consequently form a very
sharp angle with the vertebral column, which is notably indented,
while the sternum is also depressed in a groove, and occupies a plane
posterior to that of the ribs. The section of the thorax, in this case,
approaches the form of a figure 8; and the thoracic perimeter would
not represent the true measurement because it would include the empty
spaces left by the front and back depressions. The thoracic index
would also give a false idea of the facts, because the antero-posterior
diameter would be nowhere so short as at the centres of measurement for
this diameter.
The only method for representing the true shape and area of this type
of thorax is that employed by Maurel.
_Anomalies of Shape._--In addition to the preceding anomaly, very
frequent in degenerates, and associated with a _deficient development_
_of the lungs_ and with physical weakness, there are numerous other
anomalies. Among others, those that principally deserve attention are
the funnel-shaped or _consumptive thorax_, in which the longitudinal
diameter is excessive; the thoracic frame is greatly elongated and
the ribs descend to a very low level; this type of thorax is frequent
in neuropathic women, and, according to Fere, is associated with
degeneration.
The opposite form is the _barrel-shaped thorax_, in which the
prevailing diameter is the antero-posterior; it is very prominent and
is frequently met with in persons who are subject to forms of asthma,
maladies of the heart, etc.
The _bell-shaped_ thorax is similar to the preceding, but is
characterised by an accompanying exceptional brevity of the
longitudinal diameter, which causes it to resemble the infantile thorax
(arrest of morphological development).
The _grooved_ thorax is the one described above as common among the
mentally deficient.
A considerable importance attaches to a form of thorax distinguished
by the _shortness of the clavicles_, in consequence of which the chest
remains flat, paralytic or _flat thorax_ (_habitus phthisicus_).
The flattened appearance is due to the fact that the chest cannot
rise in front, and the shoulders, being cramped by the shortness of
the clavicles, curve forward, while the scapulae stand out from the
plane of the back and spread themselves like wings (scapulae alatae).
I have met with this form in deficients, accompanied by such _laxity
of articulations_, that it was possible to grasp the points of the
shoulders and draw them together until they very nearly met in front.
This form of thorax is characteristically predisposed to pulmonary
tuberculosis, and is frequently met with in the macroscelous types.
The commonest deformities of the thorax are those associated with
_rachitis_.
One of the forms regarded as being rachitic in origin is the
_keel-shaped_ _thorax_, in which the sternum is thrust forward and
isolated along its median line, like the keel of a boat.
But the thoracic deformities due unquestionably to rickets are of the
well-known types that go popularly under the name of _hunchback_,
and are accompanied by curvatures of the vertebral column. The first
admonitory symptoms are shown by the so-called _rachitic rosary_,
_i.e._, by the small swellings due to enlargement of the ends of the
ribs at their point of attachment to the sternum. Subsequently, the
softened ribs become misshapen in various ways, especially from the
fourth rib downward, the upper ribs being fastened and sustained by the
thoracic girdle and by the muscles. The curvatures of the vertebral
column which accompany rickets are _scoliosis_ or lateral deviation
(frequent in school-children) and _kyphosis_, or deviation in a
backward curve; for the most part these two curvatures occur together,
so that the vertebral column is thrust outward and at the same time is
twisted to one side: _kyphoscoliosis_.
=Pedagogical Considerations.=--The following considerations are the
natural sequence of what has been said above. Deficiency of the thorax
is one of the _stigmata_ left by the school, which in this way tends to
make the younger generations feeble and physiologically unbalanced.
The exaggerated importance which is given to the _school_ _benches_ for
the purpose of avoiding deformities of the vertebral column deserves
to be put aside and forgotten, as an aberration of false hygiene. The
bench will not prevent restriction of the thorax; before reaching the
critical point which the improved school bench is intended to prevent,
many impoverishments of the organism, fatal to robustness and health,
and often to _life itself_ (predisposition to tuberculosis!) have
been incurred; and there is no other remedy to obviate them than a
_reform in pedagogic methods_. The admonitory fact that neglected,
despised, half-starved children have an enormous _advantage_ in the
development of the thorax over the more intelligent children who are
well-fed and carefully guarded, and solely because the former are free
to run the streets, ought to point the direction in which we should
look for means of helping the new generations hygienically. They have
need of free movement and of air. The recreation rooms which tend to
keep the children of the street shut up indoors even during recess
are taking from the children of the people the sole advantage that
still remained to them. Try to realize that these children are obliged
to sleep in dark, crowded environments, and that every night, during
the period of sleep, they suffer from such acute poisoning by carbon
dioxide that they frequently awaken in the morning with severe pains
in the head. The life of the streets is their salvation. We condemn
children to death, under the delusion that we are working for their
moral good; a perverted human soul may be led back to righteousness;
but a consumptive chest can never again become robust. Let those who
talk of education and morality and similar themes be sure that they are
benefactors and not executioners, and let those who wish to do good
seek the light of science.
Curvatures of the vertebral column, such as lordosis and kyphosis,
cannot be considered solely in relation to the thorax, but in
relation to the pelvis as well, because, especially in lordosis, the
lumbar vertebrae are also involved, while the pelvis also suffers a
characteristic deformity.