922 



PERINEUM. 



or do exert much influence in supporting the 

 weight of the column of faeces within the intes- 

 tine, or in obstructing the progress of instru- 

 ments through it, may be very fairly questioned; 

 for when the rectum has been removed from 

 the dead subject and laid open, these valves 

 are in general no longer visible, and the natural 

 curvatures of the bowel explain sufficiently the 

 difficulties encountered in the introduction of 

 rectal tubes or bougies in the living. 



Bladder, vesiculte seminales, and vasa defe- 

 rentia. It is here necessary to notice briefly so 

 much of the under surface of the bladder as is 

 uncovered by peritoneum, and to consider in 

 a cursory manner the vesiculae seminales and 

 vasa deferentia. These structures are situated 

 very deeply in the perineum, and therefore they 

 are dissected with advantage from within the 

 pelvis. 



On looking down into the pelvic cavity in a 

 recent subject after the peritoneum has been 

 displaced and the bladder drawn gently to 

 either side, the anatomist obtains a satisfactory 

 view of the course and connections of the 

 recto-vesical layer of the pelvic fascia, which 

 there constitutes the superior boundary of the 

 perineum. The recto-vesical is the innermost 

 layer of the pelvic fascia ; after investing the 

 inner surface of the levator ani muscle it is 

 reflected upon the prostate gland and side of 

 the bladder, and more posteriorly upon the 

 rectum; a line drawn from the lower extremity 

 of the symphysis pubis to the spinous process 

 of the ischium is nearly the level at which this 

 reflection takes place. This fascia is closely 

 connected in front to the upper surface of the 

 prostate gland, and in that situation it forms 

 the anterior true ligaments of the bladder; it 

 next adheres to the edges of the gland, and 

 more posteriorly to the sides of the bladder, 

 there constituting the lateral true ligaments of 

 that viscus ; whilst still further back it is iden- 

 tified with the sides of the rectum as has been 

 already described. Its attachments to the blad- 

 der at either side respectively are situated a 

 little above the vesiculae seminales. 



This fascia forms the line of demarcation 

 between the perineum and the upper portion of 

 the pelvic and the abdominal cavity. It is of 

 sufficient strength to resist powerfully the des- 

 cent of any of the abdominal viscera through 

 the space between the bladder and the parietes 

 of the pelvis, and affords equal resistance to 

 the progress upwards of matter or other effu- 

 sions from below; it may be considered as a 

 sort of shelving roof to the perineum, and a 

 concave floor to the abdomen. Its density and 

 strength are at their maximum in front, whilst 

 both these properties diminish as it approaches 

 the rectum. Above it, is found a quantity of 

 loose adipose cellular membrane, continuous 

 without line of demarcation with the subserous 

 tissue of the abdomen, whilst below it are 

 situated the cellular tissue of the perineum and 

 the several parts comprised in the depths of 

 that region. His knowledge of its connections 

 teaches the anatomist that urine effused above 

 the level of this fascia must soon reach the 

 peritoneum and produce the most disastrous 



consequences; whilst the experienced surgeon 

 endeavours in every operation upon the peri- 

 neum to limit his incisions, so as to spare the 

 fascia now under consideration. 



That portion of the inferior surface of the 

 bladder which projects into the perineum is 

 bounded posteriorly by the peritoneal cul-de- 

 sac, and extends forwards as far as the prostate 

 gland, whilst the line along which the recto- 

 vesical fascia takes attachment to the bladder 

 forms its lateral limits. The dimensions of 

 this part of the bladder are exceedingly vari- 

 able, being modified by the degree of vacuity 

 or repletion of the organ itself at the time of 

 examination, as well as by the age of the 

 individual ; but its measurements are always 

 much greater transversely than from before 

 backwards. In the adult it is in general of 

 moderate extent, but it increases considerably 

 when the urinary reservoir is fully distended, 

 and it diminishes as that viscus becomes empty, 

 whilst the variable depth of the cul-de-sac of 

 the peritoneum (already dwelt upon in a former 

 part of this article) is calculated still further to 

 render its size uncertain. In the child this 

 region of the bladder scarcely exists, an ano- 

 maly explained by the pyriform shape of the 

 organ in early life, the narrow neck of the 

 bladder being then its most dependent portion, 

 and the peritoneum being prolonged very far 

 downwards towards the anus. In old age the 

 perineal portion of the bladder often exhibits 

 extraordinary developement, becoming by far 

 the lowest part of the whole organ, and form- 

 ing a pouch which projects remarkably towards 

 the rectum. In many instances calculi become 

 lodged within this depressed part of the viscus, 

 far beneath the level of the cervix vesicae, so 

 as to elude detection by the sound ; and in this 

 manner is explained the valuable assistance 

 which the finger introduced into the rectum 

 so frequently affords the surgeon in exploring 

 the bladder for a stone. The perineal portion 

 of the bladder rests in great measure upon the 

 rectum; in the middle line it is in immediate 

 contact with the gut, but towards either side a 

 part of the vesicula seminalis and vas deferens 

 is interposed. 



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 vesiculae 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 average 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- 



