724 



ORGANS OF DIGESTION. 



structures to or from it, are the umbilicus, for the transmission (in the foetus) of 

 the umbilical vessels ; the caval opening in the Diaphragm, for the transmission 

 of the inferior vena cava; the aortic opening, for the passage of the aorta, vena, 

 azygos, and thoracic duct ; and the oesophageal opening, for the oesophagus and 

 pneumogastric nerves. Below, there are two apertures on each side ; one for 

 the passage of the femoral vessels, and the other for the transmission of the 

 spermatic cord in the male, and the round ligament in the female. 



Regions. For convenience of description of the viscera, as well .as of refe- 

 rence to the morbid condition of the contained parts, the abdomen is artificially 

 divided into nine regions. Thus, if two circular lines are drawn round the 

 body, the one parallel with the cartilages of the ninth ribs, and the other with 

 the highest point of the crests of the ilia, the abdominal cavity is divided into 

 three zones, an upper, a middle, and a lower. If two parallel lines are drawn 

 from the cartilage of the eighth rib on each side, down to the centre of Pou- 

 part's ligament, each of these zones is subdivided into three parts, a middle 

 and two lateral. 



Fig. 396. The Regions of the Abdomen and their Contents. (Edge of Costal Cartilages in 



dotted outline.) 



The middle region of the upper zone is called the epigastric (tni, over ; 

 ///' .stomac/i); and the two lateral region, the right and left hypochondriac 

 uutli'.r; *of$pot, the cartilages). The central region of the middle zone is the mn- 

 lilical; and the two lateral regions the right and left lumbar. The middle region 

 of the lower zone is the hi/j>*/<i*(ric or pubic region; and the lateral regions are 

 the rig/if and /</'/ ///.'/>/ ///.a/. The viscera contained in these different regions are 

 the following (Fig. 396): 



