320 NORMAL, HISTOLOGY AND ORGANOGRAPHY. 



cavity, so flattened that the anterior and posterior 

 uterine walls touch each other. The base of the 

 cavity is in the fundus and is convex downwards. 

 The two Fallopian tubes open into the upper angles 

 each by a small aperture that will barely admit a 

 bristle. The cavity tapers gradually toward the 

 cervix, where it becomes constricted to form the in- 

 ternal os. The peritoneum covers the fundus and 



Muscular layer 



Serous layer. 

 Fig. 232. Cross section of wall of uterus. 



body of the uterus, and posteriorly extends down- 

 ward to clothe the upper posterior wall of the vagina. 

 It is then reflected back over the rectum, forming a 

 a sac called the pouch of Douglas. This makes it 

 possible to open the peritoneal cavity by a puncture 

 through the upper posterior vaginal wall, an operation 

 which establishes free drainage to the female pelvis. 



