Chapter 03 - The Thorax
Pedagogical Anthropology - English Restoration
## Chapter 03 - 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 vertebræ, 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 scapulæ, 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 scapulæ. The scapulæ 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 scapulæ (*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 resistentiæ*. 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.
![](https://www.gutenberg.org/files/46643/46643-h/images/page294.png =621x610)
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 vertebræ 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 papillæ 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 papillæ are further apart and higher up.
![](https://www.gutenberg.org/files/46643/46643-h/images/page295.png =489x611)
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*.
Quétélet 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* = (100×*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 Quétélet, 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 papillæ is about equal to the antero-posterior diameter of the thorax (hence the papillæ 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 papillæ, 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 æsthetically 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.
![](https://www.gutenberg.org/files/46643/46643-h/images/page300.png =461x371)
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 Féré, 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 scapulæ stand out from the plane of the back and spread themselves like wings (scapulæ alatæ). 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 vertebræ are also involved, while the pelvis also suffers a characteristic deformity.