POSITION OF VISCERA AT OUTLET OF PELVIS. 783 



of the finger introduced into the gut, the surgeon readily detects enlargement or 

 other disease of this organ, and he is enabled by the same means, to direct the 

 point of a catheter when its introduction is attended with much difficulty, either 

 from injury or disease of the membranous or prostatic portions of the urethra. 



Behind the prostate is the posterior surface of the neck and base of the bladder ; 

 a small triangular portion of this organ is seen, bounded, in front, by the prostate 

 gland ; behind, by the recto-vesical Ibid of the peritoneum ; on either side, by the 

 vesiculse seminales and vasa deferentia ; and separated from direct contact with the 

 rectum by the recto-vesical fascia. The relation of this portion of the bladder to 

 the rectum is of extreme interest to the surgeon. In cases of retention of urine, 

 this portion of the organ is found projecting into the rectum, between three and 

 four inches from the margin of the anus, and may be easily perforated during life 

 without injury to any important parts ; this portion of the bladder is, consequently, 



Fig. 393. A View of the Position of the Viscera at the Outlet of the Pelvis. 

 N, 



Arfery of Carpus Cavfrnngrem 

 Versa I Artery of feat* 



Artery <>J> .Enfj 

 tal futfic Artery 



Coirper'* 1 



frequently selected for the performance of the operation of tapping the bladder. 

 If the finger is introduced into the bowel, the surgeon may learn the position, as 

 well as the size and weight, of a calculus in the bladder ; and in the operation 

 for its removal, if, as is not unfrequently the case, it should be lodged behind an 

 enlarged prostate, it may be easily displaced from its position by pressing upwards 

 the base of the bladder from the rectum. 



Parts concerned in the Operation of Lithotomy. The triangular ligament must be 

 replaced, the rectum drawn forwards so as to occupy its normal position, and the 

 student should then consider the position of the various parts in reference to the 

 lateral operation of lithotomy. This operation is usually performed on the left 

 side of the perineum, as it is most convenient for the right hand of the operator. 

 A staff having been introduced into the bladder, the first incision is commenced 

 about an inch and a half in front of the anus, a little on the left side of the raphe, 

 and carried obliquely backwards and outwards to midway between the anus and 

 tuberosity of the ischium. This incision divides the integument and superficial 



