848 



LITHOTOMY. 



tion are as follows : the integument, superficial fascia, external hasmorrhoidal 

 vessels and nerves, the posterior fibres of the Accelerator Urinae, the Trans- 

 versus Perinaei muscle and artery (and, probably, the superficial perineal vessels 

 and nerves), the deep perineal fascia, the anterior fibres of the Levator Ani, 

 part of the Compressor Urethras, the membranous and prostatic portions of 

 the urethra, and part of the prostate gland. 



Fig. 460. A Transverse Section of the Pelvis, showing the Pelvic Fascia. 



Anterior CruralA'erve 



Femoral Vessels. 



Obturator Fa 



Internal Pudic fcteh t AfcrwJ^ 



Parts to "be avoided in the operation. In making the necessary incisions in the 

 perineum for the extraction of a calculus, the following parts should be avoided. 

 The primary incisions should not be made too near the middle line, for fear of 

 wounding the bulb of the corpus spongiosum or the rectum ; nor too far ex- 

 ternally, otherwise the pudic artery may be implicated as it ascends along the 

 inner border of the pubic arch. If the incisions are carried too far forward, 

 the artery of the bulb may be divided ; if carried too far backwards, the entire 

 breadth of the prostate and neck of the bladder may be cut through, which 

 allows the urine to become infiltrated behind the pelvic fascia into the loose 

 cellular tissue between the bladder and rectum, instead of escaping externally; 

 diffuse inflammation is consequently set up, and peritonitis from the close 

 proximity of the recto- vesical peritoneal fold is the consequence. If, on the con- 

 trary, the prostate is divided in front of the base of the gland, the urine makes 

 its way externally, and there is less danger of infiltration taking place. 



During the operation, it is of great importance that the finger should be passed 

 into the bladder before the staff is removed ; if this is neglected, and the incision 

 made through the prostate and neck of the bladder be too small, great diffi- 

 culty may be experienced in introducing the finger afterwards; and in the 

 child, where the connections of the bladder to the surrounding parts are very 

 loose, the force made in the attempt is sufficient to displace the bladder up into 

 the abdomen, out of the reach of the operator. Such a proceeding has not 

 unfrequently occurred, producing the most embarrassing results, and total 

 failure of the operation. 



It is necessary to bear in mind that the arteries in the perineum occasionally 

 take an abnormal course. Thus the artery of the bulb, when it arises, as some- 

 times happens, from the pudic, opposite the tuber ischii, is liable to be wounded 



