The superior region, by some called the superior fundus, is, when the bladder is empty, little more than a point prolonged into the urachus; but when distended, it presents its large and convex surface upwards and forwards ; to it is attached the superior ligament of the bladder, which consists of three fibrous cords; the urachus and the obliterated umbilical arte ries ; behind these this region is covered by peritoneum, but anterior to them it is not. The former portion is in contact with the con-. volutions of the small intestines, the latter with the recti muscles.
The inferior region, or the inferior fundus, or the base of some authors, always exists as a distinct surface, whether this organ be contracted or distended, but of course larger in the latter condition. It is rather more exten size in a transverse direction than from before backwards, and is larger and more distinct in the male than in the female : its lateral por tions in each sex are in contact with the leva tores ani muscles, and correspond to the spaces between the anus and the tuberosities of the ischium. In the female its middle portion is in contact with the vagina, in the male with the rectum in the middle line, and with the vasa deferentia and vesiculm seminales on either side; to the latter it is closely connected. The cel lular and adipose tissue on and around this region in the adult is very abundant, and con tains numerous veins.. This region is covered posteriorly by peritoneum, which extends to a transverse line connecting the centre of each vesicula seminalis. This line corresponds to the convexity of the cul-de-sac formed by the reflection of this membrane from the bladder to the rectum. In front of this line this region is covered in the middle only by a fascia and by some cellular tissue as far as the base of the prostate gland, which extends for some dis tance along its anterior portion, and on either side are the vasa deferentia and the anterior terminations of the vesiculze seminales. When the bladder is distended in the adult, this surface is enlarged, not only in superficial extent, but it also swells backwards and downwards towards the rectum, and even presses against and into that intestine, so as in some rare cases to admit of being felt by the finger introduced per anum.
To this portion the name of has fond' is com monly applied. In the adult this bas fond, that is, the posterior part of this region, is the lowest portion of the bladder, and hence cannot be evacuated except by the contraction of the organ or by surrounding pressure. In man, in advanced life, it is often found dilated into a sort of pouch, which is behind and quite below the level of the anterior part of this region, as well as of the neck of the bladder, forming in some instances of debility a sort of permanent reservoir, and one in which calculi are not un frequently contained. In the fcetus this pouch or fundus does not at all exist, the cervix or the urethral opening being then the most depend ing part, which . circumstance offers another reason for the power of retention of urine being less at that age than at a later period of life. Some writers limit the inferior region to so much of this aspect of the bladder as is uncovered by peritoneum, and therefore consider the posterior part of it as appertaining to the posterior region. Anatomically we consider this incorrect, as the vesicuke seminales are acknowledged by all to be situated on the inferior region, and the cul de-sac of the peritoneum certainly descends between these bodies to within nearly one-half or three-fourths of an inch from the prostate gland. In a practical point of view it is most essential to keep this in mind, because in the operation of recto-vesi cal paracentesis this mem brane is endangered, and would certainly be perforated if the trochar were passed through the posterior portion of this region. The sur face of the bladder which can be opened from the rectum in that operation is comparatively small; it is of a triangular form, nearly equilateral, situated on the anterior part of this region. The base is behind marked by the convex border of the peritoneal cul-de-sac : the apex is at the notch in the base of the prostate gland, and the sides are the vasa deferentia and vesiculw seminales. While all these parts are in situ, this space is but small ; when, however, the bladder has been removed from the subject, distended, and dissected, this space appears much more ample, because the peritoneum recedes from it in proportion as the attach ments of the former have been loosened.