1302 



THE UKO-GENITAL SYSTEM. 



Bladder apex 



against the anterior wall of the rectum, from which it is separated by a layer 

 of the pelvic fascia. This flattened facies posterior is separated on each side from 

 the lateral surfaces by a rounded border which, beginning above at the prominent 

 lateral part of the prostate, ends below at the apex of the organ. The apex 

 prostatae points downwards, and is in relation to the sphincter urethras membranacese 

 muscle, from which it is separated by the fascia superior of the urogenital 

 diaphragm. From the apex the rounded anterior border, which separates the lateral 

 surfaces, passes upwards in the median plane behind the symphysis pubis and retro- 

 pubic pad of fat. This border is interrupted in its lower part by the passage of the 

 urethra. 



When the sheath formed by the pelvic fascia is stripped off the prostate the 

 organ has a more rounded outline, and the surfaces just described are not so 

 clearly defined. The anterior border may now appear to be rather a surface than a 

 border, and the antero-posterior diameter of the whole organ is considerably 

 reduced. 



The urethra enters the prostate at a point near the middle of its upper surface, 

 and leaves it at a point situated on its anterior border, just above and in front of 

 the apex. As it descends, the urethra describes a curve which is concave forwards, 

 and in median section it is seen to lie, on the whole, nearer to the posterior surface 

 than to the anterior border of the gland. 



The ejaculatory'ducts, entering a slit-like interval, or hilum, situated just in front 

 of the border which separates the base from the posterior surface of the prostate, 



run downwards, medially, and forwards, 

 to open into the prostatic portion of 

 the urethra very close to one another. 

 The somewhat wedge-shaped portion 

 of the prostate, which lies between 

 these ducts and the posterior aspect 

 of the urethra, receives the name of 

 lobus medius (Fig. 1023). The base of 

 this middle lobe projects upwards 

 against the bladder, and is continuous 

 with the part of the bladder wall lying 

 immediately behind the urethral orifice. 

 When hypertrophied, as it often is in 



lobe of the 

 considerable 



elevation in the cavity of the bladder, 

 to which the term uvula vesicae is 

 applied. This elevation possesses con- 

 Drawn from a specimen hardened in situ. The lateral gamble Surgical interest (p. 1277). 

 surfaces of the prostate are seen one on each side of mi _ O r , , 



the urethra and in front of the posterior surface. ine rest ot tne prostate IS deSCrib 



as being composed of two large lateral 

 lobes, which are, however, not marked off from one another superficially. 



In front of the prostate, between it and the pubis, is a rich venous plexus plexus 

 pudendalis in which the dorsal vein of the penis terminates. This plexus : 

 continued backwards, on each side, round the lateral aspect of the prostate, ai 

 joins the large thin-walled veins which are collected for the most part in the de 

 sulcus between the bladder wall and the prostate, and form the prostatico-vesk 

 plexus. Most of the veins forming this plexus lie partly within and pai 

 outside the dense fibrous sheath of the prostate, which is derived from the viscei 

 pelvic fascia (Figs. 1023 and 1024). 



Fibrous Sheath of the Prostate. The sheath of the prostate is formed bi 

 the visceral pelvic fascia, and closely invests the gland on its lateral and posteric 

 aspects. Inferiorly at the apex of the prostate the sheath becomes continuous wit 

 the fascia superior of the urogenital diaphragm, which lies above the sphinct 

 urethree membranacese muscle, and is attached to the pubic arch. In front 

 thickened bands pass forwards from the anterior aspect of the sheath, one on 

 side of the median plane, to reach the back of the lower part of the pubis, whei 



Infero-lateral 

 area 



Ureter 



Ductus 



Posterior surface of prostate 



Seminal vesicle 



FIG. 1022. PROSTATE, URINAIIY BLADDER, AND 

 SEMINAL VESICLES SEEN FROM BELOW. 



s old people, the middle 

 prostate may cause a 



