462 A MANUAL OF ANATOMY. 



THE ABDOMEN, Interior. 



THE PERITONEUM. Fig. 94. 



The peritoneum may be called a closed sac (in the fe- 

 male it is not strictly such, as the Fallopian tubes open into 

 it) lining the abdominal cavity. Imagine the abdominal 

 cavity empty, line this throughout with a thin membrane. 

 From the back push in the alimentary canal and the organs 

 connected with it, from below the urinary viscera. The 

 thin membrane is pushed forward by the various organs 

 which receive a covering from the membrane, either com- 

 plete or partial according to the extent that they extend 

 into the general cavity. This membrane is the peritoneum, 

 the layer lining the abdominal walls is the parietal, that 

 covering the abdominal organs is the visceral. 



Leaving the adult peritoneum for the time, it will be ne- 

 cessary to follow the development of this membrane as 

 well as that of the abdominal viscera in order to gain a 

 correct idea of the relations as they are found in the adult. 

 The primitive alimentary canal is simply a straight tube ex- 

 tending along near the posterior part of the embryo and 

 held to this position by a fold of peritoneum. This fold 

 of peritoneum forms only an incomplete, vertical septum 

 through the greater portion of the abdominal cavity (Diag. 

 32, Nos. 3, 4, 5), but in the upper portion this fold extends 

 clear forward to the anterior abdominal wall (Diag, 32, No. 

 7). This portion of the septum is also joined to the under 

 surface of the diaphragm. 



The alimentary canal soon becomes differentiated by 

 growth into stomach, duodenum, small intestine, and large 

 intestine. 



The peritoneum receives different names according to the 



