This region of the bladder has received special attention from anatomists in conse quence of its presenting a small triangular space, in which the operation of recto-vesical paracentesis is, or ought to be, performed. The triangular space in question is usually small and very nearly equilateral; its base, di rected backwards and upwards, is formed by the peritoneal cul-de-sac ; the vasa deferentia and the vesicuhe seminales to the right and left respectively constitute its sides, whilst the notch in the prostate gland represents its apex. The surgeon ought to consider carefully the extent of surface which the area of this triangle comprises, as well as the avemge distance from the anus at which it is placed; for should the bladder be punctured behind this " place of election," the peritoneum must be wounded ; and should the trocar be introduced in front of it, the prostate gland and common ejaculatory ducts would be endangered, whilst the slight est deviation to either side brings the correspond ing vas deferens and vesicula seminalis into peril. In the majority of full-grown subjects the space under consideration is about three inches distant from the anus, so as to permit the index finger of the opemtor to reach it without difficulty; but from statements already made the reader will perceive that many excep tions to this rule may be encountered in prac tice. Again, the sides and base of this triangle (so long as the neighhouring parts remain in situ) are in general each of them respectively less than one inch in length; yet when the. bladder is removed from the subject and artifi cially distended, and when the connections of the peritoneum are disturbed by dissection, the space to which we refer becotnes immensely enlarged, and the anatomist is then apt to form a most exaggerated and erroneous idea of its natural dimensions.
Against the recto-vesical paracentesis many very serious objections may be raised. In early life it should not be attempted, because at that period the peritoneum descends so low, and the under surface of the bladder is so little developed, that injury to the serous membrane of the abdomen would almost necessarily en sue. Even in the adult the great uncertainty
of the depth of the peritoneal 'cul-de-sac, added to the utter impossibility of ascertaining its extent in the living subject, constitutes a weighty argument against the operation ; whilst the enlarged prostate (so very common in old men) must frequently forbid its performance in after life; and the danger of wounding the vas deferens or the vesicula seminalis, or of pro ducing urinary infiltration or a permanent fis tula, may be fairly urged against this mode of relieving the bladder, at whatever age under taken. The other methods employed for the same purpose in extreme cases of retention of urine are also no doubt open to valid objec tions, but any further consideration of this subject would be out of place iu the present article.
In order to perform lithotomy successfully, or to tap the bladder with safety, the surgeon I should ever bear in mind the direction of the Inneathfleyapdauralttimetatloe tthhee attss ao xf st hoef bt aa dt der rnu•ns of the upper strait of the pelvis ; but upon a lower plane that is to say, nearer to the pubis, if produced', it would pass superiorly through the linea alba between the umbilicus and the pubis, and it would touch the inferior extre mity of the coccyx below. In the child its direction is very variable, for the urinary reser voir being then in the abdomen and in contact with the anterior wall of that cavity, must necessarily move in obedience to the abdominal muscles, and every change of position which the bladder undergoes exerts a marked influ ence upon its axis. During childhood the axis of the bladder appears in the dead subject to run from before backwards nearly horizontally, be cause the distended bladder, no longer sup ported by the abdominal muscles turns for wards over the pubis; but in the living child, when the recti--abdominis are forcibly con tracted, the line in question becomes nearly vertical.