THE PROSTATE — THE BULBO-URETHRAL GLANDS 493 



THE PROSTATE 



The prostate (Prostata) is a musculo-glandular organ which Ues on the neck 

 of the })lacl(ler and the beginning of the urethra, beneath the rectum. It consists 

 of two lateral lobes and a connecting isthmus. 



The lateral lobes, right and left (Lobus dexter et sinister), are somewhat 

 prismatic in form, and are directed forward, outward, and somcAvhat upward. 

 The antero-internal surface of each lobe is concave and partl.y embraces the cor- 

 responding vesicula seminalis. The dorsal surface is concave and is in relation 

 with the rectum. The ventral surface is convex and lies on the obturator internus 

 muscle and fat. The apex is pointed and lies near the posterior end of the 

 superior ischiatic spine. 



The isthmus is a thin, transverse band, about four-fifths of an inch (ca. 2 cm.) 

 wide. It lies over the junction of the bladder with the urethra, the uterus mascu- 

 linus, the terminal parts of the vasa deferentia, and the necks of the vesiculse 

 seminales. Dorsally it is partly covered by transverse fibers of the urethral 

 (Wilson's) muscle. 



Structure. — The prostate is inclosed in a fibro-muscular capsule, which sends 

 thick, somewhat radially arranged trabeculae into the gland substance, dividing 

 it into spheroidal or ovoid lobules. The loljules contain a central space in which 

 the prostatic secretion (Succus prostaticus) collects. The walls of these spaces 

 are pouched out to form tubular diverticula, and the latter present saccular 

 dilatations. These cavities are all lined by cubical epithelium. There are 15 to 

 20 prostatic ducts (Ductus prostatici) on either side, which perforate the urethra 

 and open lateral to the coUiculus seminalis. The blood-supply is derived from 

 the internal pudic artery. 



The surface of the prostate is commonly tuberculate in old subjects, and amyloid bodies 

 and calcareous concretions may be found in it. 



THE UTERUS MASCULINUS 



The uterus masculinus or prostatic utricle is a rutlimentary structure of vari- 

 able size and form, situated centrally on the posterior part of the dorsal surface of 

 the bladder. When well developed, it consists of a median flattened tube, some 

 three or four inches (ca. 7.5 to 10 cm.) long, and about half an inch (ca. 1 to 1.5 cm.) 

 wide, the anterior part of which lies in the urogenital fold and gives off two slender 

 processes or cornua; the latter curve forward and outward in the fold a variable 

 distance, being sometimes traceable as far as the anterior end of the ampulla of 

 the vas deferens. The posterior extremity of the tube passes under the isthmus 

 of the prostate, and opens into the urethra on the summit of the coUiculus or joins 

 an ejaculatory duct. It has a muscular coat and a mucous lining. In many cases 

 it consists merely of a very small central tubule with a blind anterior end, or a 

 band, not at all sharply marked off from the adjacent tissue; in other cases it 

 cannot be recognized. It is interesting chiefly as being a remnant of the ducts of 

 Aliiller and the homologue of the uterus and vagina. 



THE BULBO-URETHRAL GLANDS 



The bulbo-urethral (or Cowper's) glands (Glandulae bulbourethrales) are two 

 in number, and are situated on either side of the pelvic part of the urethra close to 

 the ischial arch (Fig. 452). They are covered by the urethral (Wilson's) muscle. 

 They are ovoid in form, somewhat depressed dorso-ventrally, and their long axes 

 are directed obliquely forward and outward. In the stallion they may measure 



