PROSTATE GLAND. 595 



urethra ; but will at the same time, by means of its attachment to the 

 ring dilate the entrance of the urethra, and afford a free egress to the 

 contents of the bladder. 



The Mucous coat is thin and smooth, and exactly moulded upon the 

 muscular coat, to which it is connected by a somewhat thick layer of 

 submucous tissue, called by some anatomists the nervous coat; its 

 papillae are very minute, and there is scarcely a trace of mucous 

 follicles. This mucous membrane is continuous through the ureters 

 with the lining membrane of the uriniferous ducts and through the 

 urethra, with that of the prostatic ducts, tubuli seminiferi, and Cow- 

 per's glands. 



Upon the internal surface of the base of the bladder is a triangular 

 smooth plane of a paler colour than the rest of the mucous membrane ; 

 the trigonum vesicae, or trigone vesicate. This is the most sensitive 

 part of the bladder, and the pressure of calculi upon it gives rise to 

 great suffering. Tt is bounded on each side by the raised ridge, 

 corresponding with the muscles of the ureters, at each posterior angle 

 by the openings of the ureters, and in front by a slight elevation of 

 the mucous membrane at the entrance of the urethra, called uvula 

 vesiccE. 



The external surface of the base of the bladder corresponding with 

 the trigonum, is also triangular, and is separated from the rectum 

 merely by a thin layer of fibrous membrane, the recto-vesical fascia. 

 It is bounded behind by the recto-vesical fold of peritoneum ; and on 

 each side by the vas deferens and vesicula seminalis, which converge 

 almost to a point at the base of the prostate gland. It is through 

 this space that the opening is made in the recto-vesical operation for 

 puncture of the bladder. 



PROSTATE GLAND. 



The prostate gland (V^IO-TH/M praeponere) is situated in front of the 

 neck of the bladder behind the deep perineal fascia and upon the 

 rectum, through which it may be felt with the finger. It surrounds 

 the commencement of the urethra for a little more than an inch of its 

 extent, and resembles a Spanish chesnut both in size and form ; the 

 base being directed backwards towards the neck of the bladder, the 

 apex forwards, and the convex side towards the rectum. It is re- 

 tained firmly in its position by the two superior, and two inferior 

 tendons of the bladder, by the attachments of the pelvic fascia, and by 

 a process of the internal layer of the deep perineal fascia, which forms 

 a sheath around the membranous urethra, and is inserted into the 

 apex of the gland. It consists of three lobes, two lateral and a middle 

 lobe or isthmus ; the lateral lobes are distinguished by an indentation 

 upon the base of the gland, and by a slight furrow upon its upper and 

 lower surface. The third lobe or isthmus is a small transverse band 

 which passes between the two lateral lobes at the base of the organ. 



