1010 THE MALE ORGANS OF GENERATION. 



of the Levatores ani muscles, which are, however, separated from the gland by a 

 plexus of veins. 



The prostate measures about an inch and a half transversely at the base, an 

 inch in its antero-posterior diameter, and an inch and a quarter in its vertical 

 diameter. Its weight is about four and a half drachms. It is held in position 

 by the anterior ligaments of the bladder (pubo-prostatic] ; by the deep layer of 

 the triangular ligament, which invests the commencement of the membranous 

 portion of the urethra and prostate gland ; and by the anterior portions of the 

 Levatores ani muscles, which pass backward from the os pubis and embrace the 

 sides of the prostate. These portions of the Levatores ani, from the support they 

 afford to the prostate, are named the Levator prostates. 



The prostate consists of two lateral lobes and a middle lobe. 



The two lateral lobes are of equal size, separated by a deep notch behind, and 

 by a slight furrow upon the anterior and posterior surfaces of the gland, which 

 indicates the bilobed condition of the organ in some animals. 



The third, or middle lobe, is a small transverse band, occasionally a rounded or 

 triangular prominence, placed between the two lateral lobes at the posterior part 

 of the organ. It lies immediately beneath the neck of the bladder, behind the 

 commencement of the urethra, arid above the ejaculatory ducts, which pass through 

 the gland between its middle and lateral lobes. Its existence is not constant, but 

 it is occasionally found at an early period of life, as well as in adults and in old age. 



The prostate gland is perforated by the urethra and the ejaculatory ducts. 

 The urethra usually lies along the junction of its anterior with its middle third. 

 The ejaculatory ducts pass obliquely downward and forward through the posterior 

 part of the prostate, and open into the prostatic portion of the urethra. 



Structure. The prostate is immediately enveloped by a thin but firm fibrous 

 capsule, distinct from that derived from the recto-vesical fascia, and separated from 

 it by a plexus of veins. Its substance is of a pale reddish-gray color, of great 

 density and not easily torn. It consists of glandular substance and muscular 

 tissue. 



The muscular tissue, according to Kolliker, constitutes the proper stroma of 

 the prostate, the connective tissue being very scanty, and simply forming thin 

 trabeculse between the muscular fibres, in which the vessels and nerves of the 

 gland ramify. The muscular tissue is arranged as follows : immediately beneath 

 the fibrous capsule is a dense layer which forms an investing sheath for the gland ; 

 secondly, around the urethra as it lies in the prostate, is another dense layer of 

 circular fibres, continuous above with the internal layer of the muscular coat of 

 the bladder, and below blending with the fibres surrounding the membranous 

 portion of the urethra. Between these two layers strong bands of muscular tissue, 

 which decussate freely, form meshes in which the glandular structure of the organ 

 is imbedded. In that part of the gland which is situated in front of the urethra 

 the muscular tissue is especially dense, and there is here little or no gland tissue ; 

 while in that part which is behind the urethra the muscular tissue presents a wide- 

 meshed structure, which is densest at the base of the gland that is, near the 

 bladder becoming looser and more sponge-like toward the apex of the organ. 



The glandular substance is composed of numerous follicular pouches, opening 

 into elongated canals, which join to form from twelve to twenty small excretory 

 ducts. The follicles are connected together by areolar tissue, supported by 

 prolongations from the fibrous capsule and muscular stroma, and enclosed in a 

 delicate capillary plexus. The epithelium lining of both the canals and the 

 terminal vesicles is of the columnar variety. The prostatic ducts open into the 

 floor of the prostatic portion of the urethra. 



Vessels and Nerves. The arteries supplying the prostate are derived from the 

 internal pudic. vesical, and hgemorrhoidal. Its veins form a plexus around the sides 

 and base of the gland ; they receive in front the dorsal vein of the penis, and 

 terminate in the internal iliac vein. The nerves are derived from the pelvic 

 plexus. 



