1040 



THORAX. 



glands in the course of the trachea or bronchi ; 

 to pressure upon the trachea hy the thymus 

 gland, when later than natural in being ab- 

 sorbed, or when hypertrophied ; and to mor- 

 bid thickening of the mucous membrane of 

 the larynx, or of the trachea and bronchi 

 succeeding croup or cynanche pharyngea. 

 We concur with these views upon this sub- 

 ject, the more so as we likewise have noticed 

 the pigeon-breast in children where enlarged 

 tonsils have been present. We must not 

 imagine from this that, where there is dyspnoea, 

 there we shall always find the deformity in 

 question; for difficult breathing may be caused 

 by other circumstances than those which dis- 

 turb the counter-pressure of the atmosphere 

 in the thorax. 



IV. Dimensions of the thorax. The mea- 

 surement of the thorax may be considered 

 externally and internally; and, what is most 

 remarkable, the one class of measurements 

 may not have any relation to the other class. 

 Moreover, the external measurements bear a 

 certain proportion to the whole frame, whilst 

 the internal do not. 



(a) External measurements of the thorax. 

 The external dimensions of the thorax differ 

 much in different men ; this is obvious to 

 all. There is the broad-chested and the nar- 

 row-chested man. Mr. Brent has calculated, 

 from an extensive number of observations, 

 the following proportions, which we arrange 

 thus : 



TABLE D. Relation of the External Chest to the Height, measured over the Nipples. 



Minimum chest : \ of the stature J T of the stature = circumference of chest. 

 Medium chest : -* of the stature -4- Jg- of the stature = circumference of chest. 

 Maximum chest : \ of the stature = circumference of chest. 



For example, let us suppose a height of 61 inches, as follows, 



Minimum chest : height 61 in., \ = 30'5 in. J T = 29'5 in. circumference of chest. 

 Medium chest: height 61 in., 1 = 30'5 in. -f- ^ (= 4'07) = 34'57 in. circumference of chest. 

 Maximum chest : height 61 in., f = 40'7 in. = circumference of chest. 



Thus, by taking the most perfectly propor- 

 tioned chests, either from living figures or from 

 the classical athlette of ancient sculptures, 

 the following is the result. 



TABLE E. External Thoracic Dimensions, 

 (in three classes according to weight) in rela- 

 tion to the height, obtained from calculation. 



From this the minimum chests increase on 

 an average nearly f (3'9), the medium chests 

 rather more than f (4'2), and the maximum 

 f of an inch for every increasing inch of stature. 

 We have found from observation, upon 1276 

 cases of all various classes conjoined, a re- 

 gular arithmetical progression of the thoracic 

 circumference over the nipples in relation to 

 weight. 



By the total mean of our observations the 

 chest increases exactly one inch for every 

 10 Ibs. increase of weight, sinking the effect of 

 height, which, however, cannot well be omitted, 



because, as a general rule, the height increases 

 with the weight. 



Mr. Brent has found that twice the breadth 

 of the shoulders equals the circumference 

 of the thorax over the nipples i. e. from 

 point to point, or the caliber of the broadest 

 part of the shoulders. Thus, if the caliber 

 be 18 inches, the thorax will be 36 inches 

 in circumference. Four times the distance 

 between the nipples is equal to the circum- 

 ference. Four times the antero-posterior 

 diameter is equal to the circumference : there- 

 fore the distance between the nipples is equal 

 to the depth from before backwards of the ex- 

 ternal thorax. At the height of 5 feet 9 inches 

 this antero-posterior diameter varies from 7 

 inch, to 12^ inches. 



(b) Internal measurement of the thoracic 

 cavity. Before entering into details we may 

 observe, that the thoracic cavity is much 

 smaller than we might, perhaps, be led to 

 expect ; that the depth from above down- 

 wards is, when compared with the body, very 

 shallow. It is, however, capable of enormous 

 dilatation or mobility, even to 100 per cent ; 

 80 per cent is common. 



The absolute dimensions of the thoracic ca- 

 vity of females are obviously smaller than those 

 of males, because they are altogether of smaller 

 conformation, both in stature and weight ; 

 but, relatively, the difference is probably little, 

 Although the proportion of some of the 

 diameters may differ, yet that of the total 

 cubic measurements appears not to do so. 



A certain rude relation of necessity must 

 exist between the size of a man and the 

 dimensions of his thoracic cavity. A man 

 7 feet high will have a larger chest than 

 one 5 feet or 6 feet high. But there is no 

 constant and uniform relation of the size of 

 the chest, either to the height or weight of 



