THE PROSTATE 1021 



iiitornal piulic, and in the female some twigs are also aivcii off l»y the uterine and 

 vaginal arteries. The veins terminate in the internal iliae trunk. They form 

 plexuses whieli are especially large ahout the parts adjacent to the prostate, and 

 communicate in the male with all the veins in the neigiibourhood. Liimpli(itic>< 

 ajijiearas a subnuicous plexus wiiieh is most developed in the neigh])Ourhood of the 

 internal meatus. They accompany the veins and terminate in the internal iliac 

 glands. 



Nerves. — The nerves are derived, partly from the sympathetic system through 

 the hypogastric plexuses, partly from the cerehro-spinal system through the third 

 and fourth sacral nerves. The former supply the mucosa, the latter the muscularis. 



THE MALE REPRODUCTIVE ORGANS 



The reproductive organs of the male consist of (1) two testicles or seminal 

 glands, with their excretory tubes; (2) a musculo-glandular organ, the prostate, 

 which provides a material for the dilution of the semen, and by its sphincteric 

 contraction aids in the ejaculation of the spermatic fluid, and at the same time 

 intercepts its retrograde i)assage into the bladder; (3) an organ of copulation, the 

 penis; and (4) a canal, the urethra, which pierces the prostate and penis, and 

 serves for the transit of both the generative and urinary secretions. 



THE PROSTATE 



The prostate is a firm clastic and contractile organ, lying between the bladder 

 and the penis, and perforated by the urethra (figs. 620, 624, and 649). It is 

 roughly comparable to a horse-chestnut in form and dimensions; its broader 

 extremity or Imse lies ui)permost and l)lends with the vesical sphincter, while its 

 apex rests against the sui)erior triangular ligament. Its long axis is vertical (in 

 the erect posture), or inclines slightly forwards below (fig. 6i7), and is nearly an 

 inch and a ciuarter (3 cm. ) in length. Its transverse diameter, greatest near the 

 base, measures about an inch and a half, and its antero-posterior diameter about an 

 inch. Its average weight is a])out six drachms, nearly the same as that of the 

 testicle, and it may be noted that the active evolution of the two organs begins at 

 the same period, at puberty, and that the structural and functional development 

 of the one is intimately associated Avith that of the other during the period of 

 sexual vigor. It offers for description a base, an apex, and anterior, lateral, and 

 posterior walls. The base is connected -with the musculature of the bladder, 

 receiving the attachment of the longitudinal fiJ)res and sui'rounding the sphincteric 

 portion of the circular layer at the urethral orifice. It usually lies a little above the 

 level of the middle of the symphysis. The apex, resting against the su]ierior or 

 dee[) triangular ligament, is from one-half to three-fourths of an inch (12 to 1<S mm. ) 

 l)ehind and a little below the subpubic angle, and on rectal exploration will be 

 foTind about an inch and a (piarter above the margin of the anus. The anterior 

 wall is rounded, and is covered by the ])rostatic plexus of veins and the vcsico- 

 pul)ic nniscle and pul)o-prostatic ligaments (page 1018). The lateral walls are in 

 contact with the inner borders of the two levatores ani muscles and tlu' marginal 

 ])ortion of the venous plexus, and project al)ove and behind in the form of ill- 

 dctined lateral lobes, which may be looked upon as the jtersistent indication of 

 its development in two halves. The posterior wall is tiattened and is opjioscd to 

 the rectum, from which it is separated by some connective tissue and unstri]>ed 

 muscular filu'es continuous with the subperitoneal tissue and jx'lvic fascia. ' Near its 

 upper border is a transverse median cleft, the prostatic fissure (fig. 624), whidi 

 extends deeply inwards and forwards towards the middle of the prostatic urethra, 

 transmitting the connnon ejaculatory ducts and the sinus pocularis, and in section 



