OX POSTURE AXD ITS IXDICATIOXS. 33 



the reason that I now give has been evolved from my own brain 

 or whether I have learned it from others. 



When a man is sitting upright the diaphragm moves up and 

 down during respiration (Fig. 1G). At each inspiration it de- 

 scends and displaces the intestines and the abdominal walls out- 

 ward. During each expiration 

 the diaphragm ascends and the 

 intestines and abdominal wall 

 return back to their former posi- 

 tion. In the upright posture the 

 diaphragm moves vertically, but 

 the abdominal walls and intes- 

 tines move in a horizontal plane 

 and there is no lifting work for FlG - W. 



the diaphragm to do. The case 



is quite different when a man is lying on his back, for then the 

 diaphragm moves in a horizontal plane and the abdominal walls 

 and intestines in a vertical one. During inspiration as the dia- 

 phragm encroaches on the abdomen for the purpose of enlarg- 

 ing the thorax (Fig. 17) it has actually to raise the intestines and 

 the abdominal walls instead of merely moving them in a hori- 

 zontal plane. As the diaphragm returns into the thorax during 

 inspiration its progress will be accelerated by the weight of the 

 descending intestines, and thus the recumbent posture may be 

 sometimes useful in cases of bronchitis with emphysema, and so 

 such cases may be seen sometimes lying down although there is 

 considerable interference with the aeration of the blood. In cases 

 of cardiac disease no benefit of this kind is obtained, and there- 

 fore we find that a large proportion of those whom we see sitting 

 upright in bed in a hospital ward are suffering from disease of 

 the heart. 



When a patient lies upon his side the intestines also move in 

 a horizontal plane, and this is the position usually assumed dur- 

 ing healthy sleep, for in it there is no interference with expira- 

 tion any more than when the patient is sitting upright, while at 

 the same time the rest obtained is much more complete. The 

 side upon which one lies is immaterial to most healthy persons, 

 and they frequently lie first upon one and then on another, turn- 

 ing over perhaps several times in the course of the night ; but in 

 cardiac disease or cardiac irritability without organic disease 

 patients frequently are unable to lie upon the left side because 

 the heart beats against the ribs with such force as to cause physi- 

 cal discomfort. At the same time the heart itself appears to be 

 stimulated by the blows which it gives itself against the thoracic 

 walls and to palpitate more violently than before. The patient is 

 therefore obliged to lie upon the right side. A similar result 



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