he body is in the erect posture, for the intestines now gravitate upon
it. When the body is recumbent, the bladder recedes somewhat from the
pubes, and as the intestines do not now press upon it from above, it
allows of being distended to a much greater degree without causing
uneasiness, and a desire to void its contents.

The manner in which the bladder is connected to neighbouring parts is
such as to admit of its full distension. Its summit, back, and upper
sides are free and covered by the elastic peritonaeum, whilst its front,
lower sides, and base are adherent to adjacent parts, and divested of
the serous membrane. On tracing the peritonaeum from the front wall of
the abdomen to its point of reflexion over the summit of the bladder, we
find the membrane to be in this part so loosely adherent, that the
bladder when much distended, raises the peritonaeum above the level of
the upper margin of the pubic symphysis. In this state the organ may be
punctured immediately above the pubic symphysis without endangering the
serous sac. When the bladder is collapsed, the peritonaeum follows its
summit below the level of the pubes, and in this position of the organ
such an operation would be inadmissible, if indeed the necessity for it
can now be conceived.

By removing the os innominatum, A D, Plate 48, together with the
internal obturator, and levator ani muscles, which arise from its inner
side, we obtain a lateral view, Plate 49, of the pelvic viscera, and of
the vessels &c. connected with them. Those parts of the bladder, G, and
the rectum, C, which are invested by the peritonaeum, are also now fully
displayed. On tracing this membrane from before backwards, over the
summit of the bladder, G, we find it descending deeply upon the
posterior surface of the organ, before it becomes reflected so as to
ascend over the forepart of the rectum. This duplicature of the serous
membrane, H H, is named the recto-vesical pouch, and it is required to
ascertain with all the exactness possible the level to which it
descends, so as to avoid it in the operation of puncturing the bladder
through the rectum. The serous pouch descends lower in some bodies than
in others; but in all there exists a space, of greater or less
dimensions, between it and the prostate, V, whereat the base of the
bladder is in direct apposition with the rectum, W, the serous membrane
not intervening.

When the peritonaeum is traced from one iliac fossa to the other,