4So APPLIED ANATOMY. 



Relations. The apex rests on the posterior layer of the triangular ligament 

 I to 2 cm. (^ to y^ in.) behind and a little below the subpubic angle and just 

 inside the upper end of the anal canal. This is about 3 to 4 cm. ( i ^ to i y^ in. ) 

 above the white line of Hilton and the prostate is immediately felt by the finger as 

 soon as it enters the rectum. The prostate lies on the rectum, so that it is readily 

 accessible. Its apex being about 3 cm. (i^ in. ) from the mucocutaneous white line, 

 its upper edge would be 6 cm. (2^ in.) and the rectovesical pouch 8.75 cm. (3^ in.) 

 above this line. Thus all these structures are usually within reach of the finger. In 

 the median line, extending to each side, the vasa deferentia and seminal vesicles, if 

 diseased, as they sometimes are in tuberculous affections, can readily be felt, but when 

 healthy are too soft to be easily distinguished. On each side is the levator ani 

 muscle, which embraces the prostate as far forward as the membranous urethra, 

 where it practically blends with the deep transverse perineal and compressor urethrae 

 muscles (see recto-urethralis muscle Perineum, page 475). 



Structure. The greater portion of the prostate is composed of unstriped 

 muscular tissue, which is not only arranged peripherally but sends prolongations 

 inward, forming spaces in which the glandular tissue is lodged. There is also a layer 

 surrounding the vesical opening of the urethra. The action of this latter muscle is 

 probably to act as a true sphincter to retain the urine in the bladder. It also by its 

 contraction prevents the regurgitation of the semen into the bladder. 



Veins. In the urethral and vesical portions of the prostate are numerous 

 veins. These in the old become varicose, hence the frequency of bleeding in old 

 prostatic cases. Around the anterior portion of the prostate and laterally pos- 

 teriorly lies the prostatic venous plexus. Into it anteriorly empties the dorsal vein 

 of the penis; from above it receives the vesical veins, and in those advanced in age 

 it communicates also with the hemorrhoidal plexus posteriorly. Fenwick has shown 

 (Jour, of Anat. xix. 1885) that in the young these veins possess valves which 

 become incompetent as age supervenes. The prostatic plexus unites in a single 

 large vein on each side which empties into the internal iliac vein. 



Hypertrophy. This is the most common affection of the prostate. According 

 to Mansell Moullin it always begins in the glandular elements. It is of two kinds, 

 fibrous and glandular. Both start as glandular but the former in some cases 

 predominates and the glandular element atrophies and leaves a comparatively small 

 hard fibrous prostate. The glandular character of median growths has already been 

 explained on page 449 as originating from the prespermatic and subcervical groups 

 of Albarran. 



Glandular hypertrophy of the lateral lobes forms the ordinary large prostates for 

 which prostatectomy is performed. The bleeding, which is so common in these 

 cases of enlarged prostate, is due to the varicose condition of the veins around the 

 posterior portion of the urethra and vesical mucous membrane. 



Prostatectomy. This consists in removing the hypertrophied glandular ele- 

 ments. It is performed either suprapubically or through the perineum. 



When done through a suprapubic incision a median enlargement (so-called 

 median lobe) can readily be removed by dividing the mucous membrane with the 

 finger-nail or scissors and shelling the growth out with the finger. In this case there 

 is practically no sheath to go through and the amount of bleeding will be proportion- 

 ate to the varicose condition of the veins. If large lateral growths are to be removed 

 then there is still no fibrous sheath to be entered, but only the thin, filmy capsule and 

 fibromuscular layer of prostatic tissue covering the hypertrophied glandular masses: 

 hence for its division Freyer uses his finger-nail only. As the fibrous sheath is not 

 divided there is no bleeding from the prostatic venous plexus in its layers. 



In perineal prostatectomy two methods are used. In the first the membranous 

 urethra is opened by a median incision and then a lateral cut made into the enlarged 

 prostate on each side. The finger is then introduced and the hypertrophied glandu- 

 lar masses enucleated with the finger. In the second method a curved or A-shaped 

 incision is made from the central tendon of the perineum toward each side between 

 the rectum and tuberosities. The sphincter ani is then detached from the central 

 tendon and pushed back while the transverse perinei muscles are pulled forward. 

 The muscular fibres between the rectum and membranous portion of the urethra 



