chap, xviii.] THE BLADDER. 393 



posterior section the urethra foi ms with the cavity of 

 the bladder a curved slit (the systolic empty bladder). 

 It may be larger, and soft, with its upper surface con- 

 cave towards the abdomen, and fitting into the 

 concavity of the lower wall or surface. In the section 

 named, the urethra forms, with the bladder cavity, a 

 Y-shaped figure, the two diverging limbs of the Y 

 corresponding to the concavity named (the diastolic 

 empty bladder). When moderately distended it 

 is of rounded outline ; when completely distended 

 it assumes an oval outline, and rises out of the pelvis. 

 As distension of the bladder increases, the summit of 

 the viscus is brought more and more in contact with 

 the anterior abdominal wall, the organ becoming also 

 more convex on its posterior than on its anterior sur- 

 face. This tendency for the summit of the distended 

 bladder to press itself against the anterior parietes is 

 of good service in tapping the organ above the pubes, 

 and in suprapubic lithotomy. When greatly distended 

 it may reach the umbilicus, and may even touch the 

 diaphragm. The usual capacity of the organ is about 

 one pint, but when fully occupied it may hold some 

 quarts. When both bladder and rectum are quite 

 empty the apex of the bladder and the pre-vesical 

 reflection of the peritoneum are a little below the 

 upper margin of the syrnphysis pubis. As the 

 distended bladder ascends above the pubes it dissects 

 the serous membrane from the parietes, and the layer 

 so lifted off forms a cul-de-sac or fold of peritoneum 

 between the upper part of the anterior surface of the 

 bladder and the parietes. When the apex of the 

 bladder is two inches above the pubes the peritoneal 

 reflection is probably not more than three-fourths of 

 an inch above the same point of bone. When the 

 apex of the bladder is midway between the umbilicus 

 and the pubes there may be two inches (vertical) of 

 the anterior abdominal wall in the middle line and 



