A' NATO MY OF THE PERINEUM. 205 



the other extremity being connected with the corpus caver- 

 nosum, it forms one of the chief supports of the penis, and 

 is called the cms penis. 



The INTERNAL PUDIC ARTERY may now be sought for, 

 and will be found lying under the edge of the ramus of the 

 ischium. This artery is one of the terminal branches of the 

 iternal iliac; it passes out at the greater sacro-ischiatic 

 >ramen, crosses the spine of the ischium, and enters the 

 ilvis again by the lesser sacro-ischiatic foramen to reach 

 ramus of the ischium, about an inch in front of the 

 iberosity ; it passes along beneath the edge of this to the 

 -mphysis pubes, where, under the name of the dorsalis 

 mis, it runs the length of the organ from which it takes 

 name, to terminate in the glans penis. 



The removal of a calculus from the male urinary bladder is accom- 



ished by an operation performed in the perineum, called lithotomy, 

 bladder is reached by an incision extending from the median line, 

 n inch or more in front of the anus, backward and outward, to a 

 point midway between the anus and the tuber ischii. A part of the 

 accelerator urinse near the bulb of the corpus spongiosum, the trans- 

 versus perinei muscle, and the transverse and superficial perineal 



teries, besides the skin, superficial fascia, and triangular ligament, 

 necessarily divided, in order to reach the membranous urethra. 



e knife of the surgeon is directed by a sound introduced per 

 urethram, and by the guidance of this the membranous urethra 

 and prostate are incised, so that an opening for the extraction of the 

 stone is effected. The artery of the bulb may be wounded in this 

 operation, but the internal pudic artery can never be touched unless 

 the incision is carried too near the ramus of the ischium. 



The muscles of the female perineum differ little, except in 

 name, from those of the male. 



The constrictor vaginae surrounds the orifice of the 

 vagina, arising from the perineal centre, and is inserted into 

 the corpus cavernosum of the clitoris ; it corresponds to 

 the accelerator urinse. 



The transversus perinei is inserted into the side of the 

 constrictor vaginae. 



The erector clitoridis arises from the ramus of the ischium, 

 and is inserted into the side of the corpus cavernosum of 

 the clitoris. 



The artery of the bulb is distributed to the vagina. 



18 



Tin 



