94 



URETHROTOMY. LITHOTOMY 



possible, having first emptied the bladder if practicable, 

 since rupture of an over distended viscus may readily oc- 

 cur during violent struggles by the animal. 



The point of operation will depend upon the location of 

 the calculus or other obstacle. If it is found in the pelvic 

 portion of the urethra or in the bladder, the operation is 

 made at the ischial notch. Fig. 39. First the penis is drawn 

 out from the prepuce and the catheter introduced into the 



FIG. 39 



Urethrotomy at the ischial notch. 



urethra and pushed upward until it has passed the ischial 

 notch. After disinfection of the skin, render it tense and 

 make a 5 cm. long incision on the median line at the ischial 

 arch through the skin, bulbo-cavernosus muscle, spongy 

 portion of the urethra, and the urethral mucous membrane 

 down to the catheter, Fig. 40, k. In order to prevent infiltra- 

 tion of urine after the operation, special care is to be taken 

 to make the lower end of the wound slanting in such a 

 manner that the deeper margin is higher than the super- 

 ficial. 



