406 



urachus 



posterior border 

 Fig. 1. 



posterior border 

 Fig. 2. 



Fig. 

 Fig. 



1. Outline of the empty bladder hardened in situ, viewed from above. 



2. Outline of the empty bladder hardened in situ ; viewed from below. 



The three surfaces which approach each other at the urethral 

 orifice are each triangular in outline (fig. 2). The surface which lies 

 between the rounded borders joining the lateral angles of the bladder 

 and the urethral orifice, corresponds to the so-called base of the 

 bladder, while the two other areas together constitute the "antero- 

 inferior surface". These latter areas meet in the middle line in front, 

 where they are separated only by a rounded border extending from 

 the bladder apex towards the urethral orifice. Posteriorly they reach 

 backwards as far as the lateral angles of the organ and here they 

 are separated from one another by the entire width of the basal sur- 

 face. The term infero-lateral might be applied to each of these 

 areas; since they extend so far backwards the term anteroin- 

 ferior is not applicable. When the bladder is in situ these areas 

 are in contact with the fascia covering the levator ani muscle, with a 

 small part of that coveriug the obturator internus, and, nearer the 

 middle line, with the pubis and retro-pubic pad of fat. 



In the male the region immediately surrounding the urethral 

 orifice is flattened by contact with the upper surface of the prostate ; 

 in the female such flattening is of course absent. 



The specimens on which the above description of the empty 

 bladder is based correspond, I believe, accurately with several spe- 

 cimens prepared in Trinity College, Dublin, and in the Medical School 

 of the Catholic University, Dublin. I am indebted to Professor Cun- 

 ningham and Professor Birmingham for their kind permission to study 

 these latter specimens. 



