EMPHYSEMA OF THE LUNG. 125 



Inspection, with regard to the formation of the thorax, may give a 

 negative result even in very intense emphysema. Individuals with a 

 toose, long, so-called paralytic thorax often enough suffer greatly from 

 the disease. This will not seem strange after our having shown that 

 emphysema has no effect upon the expansion or contraction of the 

 thorax proper. In some cases, indeed, the thorax shows characteristic 

 abnormities, upon which we have founded the idea of a peculiar form 

 of the chest, " the emphysematous thorax." In this the circumference 

 and the depth, particularly in its upper and middle portion, are consid- 

 erably increased. 



Instead of presenting a broken line, the sternum forms a segment of 

 a circle ; the upper ribs are abnormally crooked, and bulged outward ; 

 the shape of the thorax is more spherical or barrel-shaped. It is remark- 

 able that absolutely erroneous views as to the mode of origin of the 

 emphysematous thorax have prevailed, while the real manner in which 

 it is produced is as clear and simple as possible. The deformity of the 

 chest is not produced by the emphysema of the lung, for both emphy- 

 sema and deformity arise from the same causes. The emphysematous 

 thorax is only seen in that species of the disease which arises from 

 forced expiration with constricted glottis, as when playing upon wind- 

 instruments, coughing, etc. By these acts the diaphragm is forcibly 

 driven up by pressure of the abdominal muscles upon the viscera of the 

 belly, and the air contained in the lung is strongly compressed. Ac- 

 cording to simple physical laws, as long as the costal cartilages retain 

 then: pliability, the thorax, like any other cavity with yielding walls, 

 must become rounded and approximate to the spherical form, wherever 

 the pressure upon it from within is augmented. But as the lower part 

 of the thorax, to which the abdominal muscles are attached, is fixed, it 

 cannot join in the rounding out of the middle and upper portions, and 

 this explains why the emphysematous thorax is more barrel-shaped than 

 spheroidal. By very deep inspirations, indeed, we can temporarily ex- 

 pand the chest to a considerable extent, but the thorax of a healthy 

 man in full inspiration is differently shaped from a so-called emphysem- 

 atous thorax. We may, for a short time, produce the latter in ourselves 

 by making the strongest possible expiratory effort, while at the same 

 time holding the nose and mouth. The sole reason for the permanence 

 of this condition in emphysematous persons is the hypertrophy and 

 alteration of the costal cartilages mentioned above. But this deformity 

 of the chest, called par excellence emphysematous thorax, is not the 

 only one observed in emphysema. In the cases in which emphysema 

 develops in consequence of long-continued forced inspiration, we do not 

 find this rounding of the upper and middle portions of the chest, in 

 which the lower takes no part ; but we find the lower portion dilated. 



