Chap. XIV] THE DIGESTIVE SYSTEM 263 



THE STOMACH 



After the oesophagus perforates the diaphragm it ends in the 

 stomach (gaster), which is the most dilated portion of the ali- 

 mentary canal. It is a hollow pouch placed obliquely in the 

 left side of the upper portion of the abdominal cavity.^ It is 

 curved upon itself, so that below it presents a long, rounded 

 outline, called the greater curvature, and above, a constricted, 

 concave outline, called the lesser curvature. 



The greater curvature is directed to the left, and the lesser 

 curvature faces mostly to the right. 



The fundus, or cardiac, end is the greater extremity, which pro- 

 jects several inches to the left of the oesophagus and is in contact 

 with the spleen. The opposite or smaller end is called the pyloric 

 extremity and lies under the liver. 



The central portion between the fundus and pyloric extremity 

 is called the intermediate region. 



The stomach has necessarily two openings : the one leading 

 into the oesophagus is usually termed the cardiac aperture ; 

 the other, leading into the small intestine, the pyloric. Both the 

 cardiac and pyloric apertures are guarded by strong circular bands 

 of muscle which are normally in a state of contraction. By this 

 arrangement, the food is kept in the stomach until it is ready for 

 intestinal digestion, when the circular fibres guarding the pyloric 

 aperture relax and allow it to pass. 



When distended, the stomach measures about fifteen inches 

 (38 cm.) from end to end and about five inches (13 cm.) antero- 

 posteriorly, and has a capacity of about one quart. The above 

 description applies to the position and form of the stomach when 

 normally filled with food, but the student must bear in mind 

 that, when empty, the stomach contracts down so as more nearly 

 to approach a true cylinder, the contraction and dilatation 

 affecting more the greater curvature than the lesser. When 

 contracted, the stomach is shorter as well as of lesser diameter. 



Coats of the stomach. — It has four coats : from the out- 

 side, (1) serous, (2) muscular, (3) submucous or areolar, and 

 (4) mucous. 



(1) The serous coat is formed by a fold of the peritoneum. The 



1 Epigastric and left hypochondriac region. 



