TREATISE ON ANATOMY. 



BOOK IV. U 



V or 



PART II. 



Organs of Assimilation. 



CHAPTER I. 



OF THE ABDOMEN GENERALLY. 



THE cavity of the abdomen occupies the space between the 

 inferior surface of the diaphragm and the outlet of the pelvis; 

 a considerable part of it is, therefore, within the periphery of 

 the lower ribs above, and of the pelvis below. It is completely 

 separated from the cavity of the thorax by the diaphragm, with 

 the exception of the foramina in the latter, for transmitting the 

 aorta, the ascending cava, and the oesophagus. It is bounded, 

 below, by the iliaci interni, the psoae, and the levatores ani 

 muscles; on the front and sides by the five pairs of muscles 

 called abdominal; and behind by the lesser muscle of the dia- 

 phragm, the Quadrat! Lumborum, the lumbar vertebrae, and 

 the sacrum. The figure of this cavity is, therefore, too irregu- 

 lar to admit of a very rigid comparison with any of the com- 

 mon objects of life; but a little reflection, on the course of its 

 parietes, will make it perfectly understood. It should be 

 borne in mind, that the very great projection of the lumbar 

 vertebrse forms for it a partial vertical septum behind ; which, 



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