In infants the muscular structure of the prostate is practically continuous with the muscular structures of the vesical walls. As the subject grows older a certain amount of circumscription and rein forcement of the prostatic muscular tissue seems to occur, so that there is a more distinct line of demarcation between the prostatic and vesical muscular tissue, although the circular fibres of the prostate are still continuous at the outlet of the bladder with the false sphinc ter of that organ.
On section the prostate is of a pale reddish color, rather dense and firm, and quite friable, the fibro-muscular elements being con tained in a proper fibrous capsule. The impression derived from the usual descriptions of the prostate is that its glandular and conse quently its most important elements from a functional standpoint are contained within the proper fibrous capsule of the organ. This, the author is convinced, is an error. The principal glandular elements of the prostate are outside the circumscribed structure which we know as the prostate body proper, in the tissues surrounding the prostate, seminal vesicles, and neck of the bladder. The glands and ducts are numerous and form the tissue mass of which the seminal vesicles con stitute the most important part. This tissue is richly supplied with nerves and blood-vessels. A consideration of this particular feature of the anatomy of the prostate serves to explain the obstinacy of infectious diseases involving this organ. It lays peculiar emphasis upon the oft-repeated assertion of the intrinsic incurability of gonor rhoeal infections of this part. A careful dissection of the prostate and its associated glandular structures about the neck of the bladder is very interesting to those who believe that deep gonorrhoeal infections in the male are to be speedily cured by instillations of a few drops of nitrate of silver solution into the prostatic urethra.
The muscular elements are arranged in a circular fashion forming posteriorly a rather distinct muscular ring, constituting the dividing line between the vesical cavity and the true vesical neck, i.e., the prostatic urethra. This ring of circular fibres constitutes the inter nal or false sphincter vesica3. Anteriorly the muscular fibres of the prostate are continuous with the accelerator urine muscle surround ing the membranous urethra. It would be difficult to say whether or not the false sphincter vesicm is a part of the muscular structure of the vesical wall, or of the prostate. The question is of no great mo
ment, inasmuch as there is practically a structural and functional con tinuity between the prostate and bladder muscle even in the adult. The tendency has been rather in the direction of a too arbitrary differentiation between the two organs, a differentiation which is hardly warrantable from a physiological standpoint, except in so far as the sexual function of the prostate is concerned.
The circulatory supply of the prostate is very abundant. The arteries are derived from the internal pudic, hemorrhoidal, and vesi cal. The veins form an elaborate and intricate plexus about the organ, inosculating with those supplying the rectum and anus in a very intimate manner. This peculiar relationship of the vascular supply of the rectum, anus, and prostate explains to a certain de gree the close pathological relationship of these structures. Thus hemorrhoids, constipation, and hepatic obstruction are liable to lead to passive congestion of the prostate, and even predispose to ac tive inflammation. Conversely, inflammatory and congestive distur bances of the prostate are apt to produce rectal tenesmus, hemor rhoids, or even proctitis. Thompson has called attention to the fact that the veins of the prostatic plexus are prone to become tortuous and varicose in elderly subjects. This condition of the veins is often associated with a similar condition of the hemorrhoidal vessels.
The nerve supply of the prostate is derived mainly from the hypo gastric plexus. The organ is most liberally supplied with filaments from the sympathetic. This sympathetic supply is closely associated with that of the rectum and anus, a relationship which in some cases forms another strong link of pathological connection between the two organs. By a consideration of the nerve anatomy of these parts we are able to understand the strangury, spasmodic stricture, and reten tion of urine which not infrequently occur as a result of operations about the rectum and anus. The elaborate sympathetic nerve supply of the prostate, and particularly of the prostatic urethra, is explana tory of the more or less remote reflex disturbances, both mental and physical, that so frequently occur as a result of prostatic disease. By means of the sympathetic nerve supply the prostate is brought into most intimate relations with all the organs in the function of which the sympathetic ganglia play an important role.