ij | THE BLADDER. 1099 
plice ureterice, and are pr oduced by the terminal parts of the ureters as they 
traverse the bladder wall (Fig. 747). Round the urethral orifice are a number of 
minute radially-disposed folds which, disappearing into the urethra, become 
continuous with the longitudinal 
folds of the mucous membrane 
of the first part of that canal. 
The ureters pierce the bladder 
wall very obliquely, and so 
the minute opening (orificium 
ureteris) of each has an elliptical 
outline. In the empty bladder 
the urethral orifice and the open- 
ings of the two ureters le at 
the angles of an approximately Orificium 
equilateral triangle, whose sides 
are about one inch in length. 
When the bladder is distended, hidye coumectmetmeters 
the distance between the open- gat Mapa Se Pl hen toe 
Sit : ox 1G. 747.—VIEW OF THE INTERIOR OF THE BLADDER IN THE 
Ings may be increased to one and REGION OF THE URETHRAL ORIFICE. 
a half inches or more. 
Peritoneal Relations and Connexions of the Bladder.—We have already 
seen that the superior surface of the empty bladder is covered by peritoneum, which 
leaves it along the lateral border on each side to reach the pelvic wall about the 
level of the white line (arcus tendineus) of the pelvic fascia. To this peritoneal 
reflexion the term lateral false (or peritoneal) ligament is usually applied. The 
lateral ligaments of opposite sides are continuous in front at the bladder apex, in 
which position the peritoneum is conducted over the fibrous cord of the urachus to 
reach the anterior abdominal wall, forming the so-called anterior false (or peritoneal) 
ligament. When the bladder is empty the level of this anterior reflexion les just 
behind or just below the upper margin of the symphysis pubis. When the bladder 
becomes filled the level of the peritoneal reflexion forming the anterior false haament 
is raised upwards, and may reach a point two inches or more above the upper margin 
of the symphysis pubis. Similarly, the line along which the lateral peritoneal 
hgament reaches the pelvic wall is also carried upw ards in distension of the bladder, 
and may reach the level of the vas deferens or of the obliterated hypogastric artery. 
When the bladder is empty the peritoneum is carried downwards upon the side 
wall of the pelvis as low as the lateral border of the organ, and lines a: groove or 
depression in this position which receives the name of paravesical fossa. As the 
bladder fills the peritoneum is raised off this fossa, and certain structures, such as 
the obturator vessels and nerves and the vas deferens, which lie in the floor of the 
fossa, come into direct relationship with the side wall of the distended bladder. 
Posteriorly the peritoneum leaves the upper surface of the empty bladder at its 
posterior border, and is carried backwards, forming a kind of horizontal shelf « 
fold for a distance of about half-an-inch, giving at the same time a partial cover- 
ing to the vasa deferentia and upper ends of the seminal vesicles. The peritoneum 
then suddenly dips downwards to reach the bottom of the recto-vesical pouch, 
where it is reflected on to the anterior surface of the rectum (Fig. 749). Asa rule, 
no part of the basal surface of the contracted and empty bladder receives a cover- 
ing from the peritoneum, since the seminal vesicles and terminal portions of the 
vasa deferentia intervene as they lie in the anterior wall of the recto-vesical pouch. 
When the bladder is distended the posterior border, separating the upper and basal 
surfaces, is rounded out, and the peritoneum forming the horizontal shelf, just 
deseri bed, is taken up (compare Figs. 736 and 738). It is to be specially noted 
that the level of the peritoneal reflexion, forming the bottom of the recto-vesical 
pouch, does not alter to any considerable extent in distension of the bladder 
(Figs. 737 and 738). 
An examination of mesial sections of the pelvis shows the great danger run by the ampulle 
of the vasa deferentia in the operation of puncturing the bladder through the anterior wall of the 
rectum, while avoiding at the same time injury to the peritoneum. 
M\ Folds in 
\\ mucous coat 
n Orificium 
1’ — urethra 
internum 
Trigonum 
vesice 
