240 SPECIAL ANATOMY. 



473. 4. The Urethra, 



is the narrow, cylindrical continuation of the neck of the bladder 

 which passes under the symphysis pubis and opens with an 

 external mouth, osteum cutaneum, on the external parts of gene- 

 ration. 



a. The urethra of the male, urethra virilis, from five and a 

 half to nine inches long, four lines broad, passes obliquely for- 

 wards and downwards through the Prostate (pars prostat.) 

 curves, slightly arched downwards, in its course, under the Sym- 

 physis (pars membran.}, and lies in a groove between the corpp. 

 cavern, on the inferior surface of the penis (pars cavernosa), 

 whence it passes forwards through the glans to its anterior mouth. 



1. Pars prostat ica perforates the prostate (or lies in a groove uncovered by 

 it above), is wider at its departure from the neck of the bladder than before, 

 and about ten lines to one inch long. On the posterior wall the mucous mem- 

 brane forms a narrow fold, caput gallinaginis (colliculus seminalis, veru monta- 

 wwra), upon which are found the two openings of the ductus ejaculatorii, and 

 on the sides of which are the excretory ducts of the Prostata, and several ra- 

 diating bands, frenula. Between Prostata and mucous membrane there is 

 placed, as in the urinary bladder, a layer of muscular fibres. 



2. Pars membranacete s. isthmus urethra, the narrowest part of the urethra 

 (one and a half to two lines diam.) is eight to nine lines long, formed only 

 of the mucous membrane and the m. constrictor urethra [Wilson's and 

 Outline's}, surrounding it like a ring, lies curved under the Symphysis pubis, 

 separated from this by veins, above the rectum (between the two a triangular 

 space, the apex of which looks backwards and upwards). This portion per- 

 mits great distension. The muscular layer is surrounded by many veins. 

 [This portion perforates the two layers of the deep perineal fascia about one 

 inch below the angle of the pubes, three-fourths to a half below the subpubic 

 ligament. The bulb of corp. Spongiosum projects backwards upon its under 

 surface, being applied to the anterior surface of the deep fascia.] 



3. Pars cavernosa s. spongiosa, the longest portion of the urethra, commences 

 with an enlargement, bulbus, which has a diameter of about three lines, is 

 placed in the apex of the pubic angle, is surrounded below by the corp. caver nos. 

 [spongiosum] urethra, which likewise forms a bulbus, and laterally by the mm. 

 bulbo-cavernosi and Cowper's glands, and looks forwards and upwards. From 

 the angles in which the roots of the corpus cavernos. unite, the urethra passes 

 on the inferior surface of the penis, at first above mm. bulbo-cavernosi, then close 

 above the skin to the glans ; is there enlarged (four lines wide, three-quarters 

 of a line long) into the (fossa navicularis s. Morgagni), passes through the 

 middle of the glans [rather, on its under surface], and terminates with a nar- 

 row, oval opening (two lines wide) at its point. This portion consists of a 

 fibrous sheath, a spongy body, and the mucous membrane, which here pre- 

 sents particular longitudinal folds, and the oblique mouths of Cowper's glands 

 directed forwards, and those of mucous glands (gl. Littrii) in larger depressions 

 (lacuna s. sinus Morgagni). 



Vessels of the urethra are numerous, especially in the fossa navicularis. 

 Nerves also from pudendo-hcemorrhoidaL 



b. The urethra of the female, urethra muliebris, about an inch 

 and a half long, and wider than that of the male ; passes, only 



