LITHOTOMY 



377 



found throughout the entire operation, but especially during 

 the abstraction of a stone whose size necessitates perfect re- 

 laxation of the urethral wall. The contraction of the strong 

 .urethral muscle against the stone prevents successful abstrac- 

 tion. 



INSTRUMENTS, ETC- 



Scalpel. 

 Dissecting forceps. 

 Artery forceps. 

 Lithotomy forceps. 

 Lithotrite (if needed). 

 Evacuator (if needed). 

 Catgut, silk and needles. 

 " Antiseptics. 

 Catheter. 



Fig. 189 

 Figs. 188 and 189— Lithotomy Forceps. 



First Step (Urethrotomy). — The catheter is passed into 

 the bladder to facilitate incision of. the urethra. 



The incision is made two inches long from the anus down- 

 ward, so that the urethra is approached from above rather 

 than from behind. It is made in the median line and the fol- 

 lowing integuments, which are distinct membranes, are 

 divided consecutively : The skin, the superficial perineal 

 fascia, the deep perineal fascia, the accelerator urinae muscle, 

 and the urethral mucosa. As the urethra pitches forward at 

 this point, the incision into it is almost horizontal. 



Second Step. — Extraction of the Stone. — The catheter is 

 now withdrawn, and a pre-operative estimate of the dimen- 

 sion of the stone having been made, a forceps of the proper 

 size is passed into the bladder and fixed upon the stone with 



