THE PERINEUM 379 



In the deep perineal pouch, the internal pudendal gives off 

 the important artery to the bulb, which runs medially and pierces 

 the inferior fascia of the urogenital diaphragm near the middle 

 line in order to reach the bulb. It usually lies three-quarters 

 of an inch from the base of the diaphragm. In the old operation 

 of lateral lithotomy, the point of the knife was entered i inches 

 in front of the anus and just to the left of the middle line, and 

 was carried backwards and laterally through the left ischio- 

 rectal fossa towards a point midway between the anus and the 

 tuber ischii. In this way the whole of the incision lay behind 

 the artery to the bulb. The posterior fibres of the bulbo- 

 cavernosus and the superficial transverse perineal muscle and 

 artery were divided in the anterior part of the wound, and the 

 urethra was reached by incising the inferior fascia of the 

 urogenital diaphragm and the sphincter urethrae. The point 

 of the knife was then carried along the grooved staff into the 

 bladder, cutting through the left lobe of the prostate and its 

 sheath. 



Perineal Prostatectomy. In this operation the prostate 

 is approached from below and behind. 



An incision, convex forwards, is made between the ischial 

 tuberosities, and the skin and fasciae are reflected until the 

 superficial transverse perineal muscle is exposed and the base 

 of the urogenital diaphragm defined. The recto-urethralis 

 muscle is then exposed and divided transversely. The fingers 

 may now be inserted into the cellular interval between the 

 prostate and the rectum and the two viscera can readily be 

 separated. The urethra is then incised at the apex of the 

 prostate, by cutting on a staff with a median groove. The 

 incision should not be more than a third of an inch long and 

 should not injure the sphincter urethrae. The staff may then 

 be withdrawn and Young's prostatic tractor is passed into the 

 bladder through the incision in the urethra. By its means, 

 the prostate is drawn downwards and backwards till it appears 

 in the wound. Its sheath is then incised on each side, and the 

 two halves of the prostate are removed separately. 



This operation was introduced by Young, of Baltimore, with 

 a view to preserving the ejaculatory ducts and the prostatic 

 urethra. Further, the mucous coat of the bladder is not 

 interfered with, and perineal drainage is obtained through the 

 urethral wound. 



Development of the Genito-Urinary Organs. The part of the gut 



