THE PERITONEUM. I2 r 



plica umbilicalis lateraiis and the plica umbilicalis media. The three foveas which have just 

 been mentioned are above Poupart's ligament and may be seen and felt upon the inner surface 

 of the anterior abdominal wall. The femoral fossa (fovea femoralis) is below Poupart's ligament, 

 opposite to the fovea inguinalis medialis. In this situation the peritoneum covers the femoral 

 ring (annulus femoralis), which is also called the internal femoral ring (see page 143 and Figs. 

 56, 58, and 76). With the aid of Fig. 56 the reader should firmly fix in his mind that inguinal 

 hernias pass out above Poupart's ligament, while the femoral variety makes its exit below this 

 structure. The external inguinal fossa gives passage to the external oblique or indirect inguinal 

 hernia ; the internal inguinal fossa is the site of the internal or direct inguinal hernia. The very 

 rare internal oblique inguinal hernia (hernia inguinalis obliqua medialis) passes out through the 

 fovea supra vesicalis. 



THE PERITONEUM. 



The peritoneum is attached to the inner surface of the abdominal wall by loose connective 

 tissue and is consequently more or less movable. It is also very elastic, as may be seen after 

 recovery from ascites, pregnancy, or tumors, where the previously distended peritoneum forms 

 no persisting folds. The relation of the peritoneum to the viscera is similar to that of the pleura 

 to the lungs, so that we differentiate a parietal layer, covering the inner surface of the abdominal 

 wall, and a visceral layer, reflected over the abdominal organs. If we imagine that most of the 

 viscera grow into the peritoneal cavity from behind, it will be apparent that they are connected 

 to the posterior abdominal wall by reflections of the peritoneum. These peritoneal duplicatures 

 are known in general as peritoneal ligaments; that of the intestine is called the mesentery, while 

 that of the colon is the mesocolon. If the ligament is very long, the organ is naturally more mov- 

 able (the mesentery of the intestine, for example); while if it is short and broad, the organ is 

 more fixed (the coronary ligament of the liver). The organs are also connected with each other 

 by similar peritoneal ligaments or duplicatures (liver and stomach, stomach and colon). If the 

 viscera remain against the posterior abdominal wall so that only a small portion of their ventral 

 surfaces possesses a peritoneal covering, we say that they are situated outside of the peritoneal 

 cavity (the pancreas and the kidneys). This relation and the following ones will be made clearer 

 by a study of Fig. 59. 



If we open the peritoneal cavity by an incision in the linea alba, we find behind the ligamentum 

 duodenale* (passing from the inferior surface of the liver to the duodenum) a foramen which is 

 called the foramen epiploicum, or foramen of Winslow. This leads us into a second space, sepa- 

 rated from the general peritoneal cavity in its course of development, which is known as the 

 bursa omentalis or lesser peritoneal cavity, and extends downward behind the stomach, originally 

 as far as the free border of the great omentum. In rare cases viscera (intestines) have been found 

 projecting through a dilated foramen of Winslow into the lesser peritoneal cavity (a variety of 

 internal hernia), and in such cases symptoms of strangulation may be produced by the constric- 

 tion at the foramen of Winslow. The great rarity of this hernia is due to the protected position 

 of the foramen and to the overlying liver. 



Under normal conditions the abdominal viscera fill the abdominal cavity in such a manner 



* Better known to American and English readers as the right free edge of the gastro-hepatic omentum. 



