58 PERSONAL APPEARANCES IN HEALTH AND DISEASE. 



chest when it is full of air so as to give greater support 

 to the large pectoral muscles going to the arms the lung 

 becomes permanently enlarged, arid the ribs maintain 

 more or less their position of full inspiration, viz.: the 

 horizontal. In that way the barrel-shaped chest, as it is 

 termed, is brought about it is deep from before back- 

 wards and instead of having its external diameter longer 

 than its antero-posterior, both diameters may be equal, so 

 that the circumference of such a chest is round. Hence, 

 although the lungs are so large, breathing is more 

 laboured and difficult, for the ribs are raised to their full 

 extent and no longer move in breathing ; and the neces- 

 sary enlargement of the capacity of the thorax has to be 

 brought about mainly by the movements of the dia- 

 phragm, and the forcible raising of the upper ribs by 

 the muscles passing to them from the neck. 



Although the most frequent cause of change in the 

 form of the chest depends on the condition of the lungs, 

 yet, especially in childhood, when the ribs are .soft and 

 yielding, the heart if greatly enlarged will cause a con- 

 siderable bulging of the chest-wall over it. 



The abdomen having only soft and fleshy walls is liable 

 to any amount of variation from the condition of the 

 organs contained within it, and as some of these organs 

 the stomach and intestines are very distensable, and vary 

 in capacity and in amount of their contents several times 



