ABDOMEN AND PELVIS 539 



Male Urethra (Urethra virilis). 



Review at this stage of your dissection the general direction 

 of the urethral canal, also the variations in the diameter of its 

 lumen in different parts. Study the following (Fig. 289) : 



(a) Prostatic part (pars prostatica). (Vide Spalteholz, Fig. 643.) 



(aa) Urethral crest (crista urethralis). 



(ab) Seminal hillock (colliculus seminalis). 



(ac) Prostatic utricle (utriculus prostaticus). 



Pass a probe into the prostatic utricle and determine its 

 length. What is its homologue in the female? It is of 

 importance surgically, as it may render difficult the passing 

 of a small sound or bougie and may harbor infection. 



(ad) Mouth of ejaculatory ducts. 



Pass a bristle into the duct and determine its general 

 course and direction. 



(ae) Prostatic ducts (ductus prostatici). 



Squeeze the prostate. The fluid that exudes is the pros- 

 tatic juice (succus prostaticus). 



(af) Prostatic muscle (M. prostaticus). 



(b) Membranous part (pars membranacea) . 



Note the fixity of this part, also the narrowness of the lumen. It 

 is the portion most frequently ruptured. Being the narrowest part 

 of the urethra, it is also the most frequently involved in stricture. 



(c) Cavernous part (pars cavernosa). 



(ca) Navicular fossa of urethra (fossa navicularis urethrae [Mor- 



gagnii] ) . 



(cb) Valve of navicular fossa (valvula fossae navicularis). 



(cc) External urethral orifice (orificium urethrae externum). 



(cd) Urethral lacunae of Morgagni (lacunae urethrales [Mor- 



gagnii]). 



(ce) Urethral glands of Littre (glandulae urethrales [Littrei]). 



To complete this study the student should examine sections 

 of the prostate and penis under the dissecting microscope. 



Wall of the Seminal Vesicle. (Vide Spalteholz, Fig. 653.) 



Straighten out the seminal vesicles and study the following 

 coats : 



(a) Adventitious coat (tunica adventitia). 



(b) Muscular coat (tunica muscularis). 



(c) Mucous coat (tunica mucosa). 



