194 APPLIED PHYSIOLOGY 



for instance, in women in whom the normal function of 

 the abdominal muscles has been largely usurped by the 

 support given by corsets, then the descent of the liver 

 and the organs lying beneath it is unopposed, and a dis- 

 location downwards of the abdominal viscera takes place, 

 a condition known in clinical medicine as Gl^nard's 

 disease. It might be supposed, from a study of the 

 anatomical relations of the diaphragm, that it would 

 tend to pull the ribs inwards quite as much as to elevate 

 them;* but such an action is prevented partly by the 

 resistance offered by the comparatively solid mass of the 

 liver, partly by a fixation of the ribs by the intercostal 

 muscles. As a matter of fact, when the latter are 

 paralyzed, as happens, for example, when there is a 

 transverse lesion of the cervical cord or when the ribs 

 are already much raised, as in emphysema, a recession 

 of the ribs along the line of attachment of the diaphragm 

 can be observed to take place. 



The slight descent of the central tendon of the 

 diaphragm, which takes place during inspiration, pulls 

 down the heart with it, and so provides a still larger 

 space into which the lungs can expand. This descent 

 of the diaphragm is aided in the vertical position by the 

 action of gravity, but in the case of a patient lying on 

 his back the liver has got to be pushed upwards instead 

 of downwards, and so the easy descent of the diaphragm 

 is impeded. It is for this reason, in part, that patients 

 in whom the respiration is embarrassed prefer to sit 

 up in bed. An accumulation of fluid or gas in the 



* Gerhardt, ' Ueber Inspiratorische Einziehungen am Thorax,' 

 Zeit.f. Klin. Med., 1896, xxx. 37. 



