1THE STOMACH. 1163 



esenteries are folds of peritoneum which unite portions of the intestine 

 ^o cue posterior abdominal wall, and convey to them their vessels and nerves. 

 [ There are several mesenteries, e.g. the mesenterium (mesentery proper), which 

 connects the jejunum and ileum to the posterior abdominal wall, the mesocolon 

 transversum (transverse mesocolon), the mesocolon pelvinum (pelvic mesocolon), 

 ' and occasionally others. 



Other folds, specially named, but described elsewhere, are the ligaments of the 

 liver, the so-called " false ligaments " of the bladder, the lieno-renal ligament, and 

 the broad ligaments of the uterus. 



VENTEICULUS. 



The stomach is the large dilatation found on the digestive tube immediately 

 after it enters the abdomen (Figs. 916 and 920). It constitutes a receptacle in which 

 the food accumulates after its passage through the oesophagus, and in it take 

 place some of the earlier processes of digestion, resulting in the conversion of the 

 food into a viscid soup-like mixture, known as chyme. The chyme as it is formed 

 is allowed to escape intermittently through the pylorus, in to the small intestine, where 

 the digestive processes are continued. 



The form and the position of the stomach present great variations, not only 



among different individuals, but also in the same individual at different times. 



The degree to which it is filled, the size and position of adjacent organs, the con- 



' dition of the abdominal walls, and even the assumption of the erect or the recumbent 



attitude can influence its shape and relations. 



Of recent years, examination of the stomach by X-rays has afforded information, 

 otherwise unattainable, of the shape and position of the stomach in life, and of the 

 ( changes which it undergoes. The results obtained by this method have consider- 

 ably modified current conceptions regarding the stomach in the living. A necessary 

 preliminary to the proper comprehension of these appearances is a careful study 

 of the stomach as it presents itself to anatomical examination. 



General Shape and Position. In shape, the stomach may be described as an 

 irregularly piriform or conical organ, with a wide end directed upwards and 

 backwards, lying deeply in the hollow of the diaphragm, mainly in the left hypo- 

 chondriac region, and a narrow tapering extremity which passes downwards and 

 forwards, and is bent over to the right side, in the epigastric region. 



The long axis of the organ forms a spiral curve, directed downwards, anteriorly 

 and to the right, and finally backwards. 



The superior end, or fundus, is almost always dome-shaped, and is distended with 

 gas, and its wall is thinner and more flaccid than that of the lower portion, which 

 . is thicker and somewhat cylindrical in shape. 



The walls of the stomach are composed of an inner thick layer of mucous membrane (tunica 



, mucosa), supported by submucous tissue (tela submucosa), a muscular coat, consisting of three 



layers, more or less complete, of muscle fibres (tunica muscularis), running in different directions, 



vered externally by a serous, peritoneal investment (tunica serosa). The special characters of 



' each of these walls will be described later. 



The stomach presents the following parts for examination : 



Two surfaces, an anterior (paries anterior) directed at the same time forwards and 



to the left, and a posterior (paries posterior) which looks posteriorly and also to the 



right. These surfaces meet above and to the right at the lesser curvature, curvatura 



ainor, and below at the greater curvature, curvatura major. At the superior end of 



3 lesser curvature the oesophagus enters the stomach, at the oesophageal opening, 



while at the inferior end the stomach passes into the duodenum at the pylorus. 



3 dome-shaped portion to the left of the CBsophagus is the fundus, while the 



Bmainder of the stomach is divisible into the body, corpus ventriculi, and the 



pyloric portion, pars pylorica. 



The cesophageal opening is termed the cardia, and the portion of the stomach 



ijacent to it the pars cardiaca, while the inferior orifice is termed the pylorus, and 



the portion of the stomach adjacent to it is the pars pylorica, a dilated portion of 



