210 SURGICAL ANATOMY OF 



pouch on either side of and below the urethra, in which 

 lie Cowper's glands. 



On detaching this posterior layer, the anterior fibres 

 of the levator ani are seen, passing by the sides of the 

 prostate, and uniting on its perineal surface with the 

 muscle of the opposite side, and blending at the central 

 tendon with the fibres of the external sphincter and 

 transverse perineal muscles. The central fibres are in- 

 serted into the side of the rectum, interlacing with the 

 sphincters, and the posterior are attached to the coccyx 

 and median raphe behind the rectum. These muscles 

 and the triangular ligament shut in the inferior outlet 

 of the pelvis. 



In order to obtain a view of the relations of the 

 structures which lie at the inferior outlet of the pelvis, 

 as they would be met with in a surgical operation, the 

 rectum should be detached from its connections by di- 

 viding the anterior and lateral portions of the levator 

 ani, and pulled backwards, when the under surface of 

 the prostate, the neck and base of the bladder, vesicular 

 seminales, and vasa deferentia will be seen (Fig. 36). 



The general form of the normal prostate is that of a 

 chestnut, with its base directed towards the bladder, and 

 its apex towards the symphysis, having its longest diam- 

 eters antero-posteriorly, and at its base transversely. 

 Its inferior surface rests flat on the triangular ligament 

 and membranous portion of the urethra ; its upper sur- 

 face, slightly concave, is intimately connected with the 

 bladder and ejaculatory ducts, which lie together in the 

 middle line immediately behind it. Its anterior surface 

 corresponds to the deep layer of the triangular ligament 

 (pubo-prostatic ligament); the posterior surface is sepa- 

 rated from the rectum simply by a little cellular tissue 



