but 



THE MALE UEETHKA. 



1307 



ut in it can often be traced as a slight median ridge as far as the uvula vesicse. 

 When followed in the opposite direction the ridge becomes less marked, and 

 can be followed on the urethral wall into the membranous portion of the canal, 

 where it divides into a pair of inconspicuous folds or elevations, which gradually 

 fade out into the urethral wall (Fig. 1026). 



The curvature and, to a less degree, the length of the prostatic urethra depends 

 upon the amount of distension of the bladder and of the rectum (compare Figs. 989 

 990). 

 Pars Membranacea Urethrse. The second, or membranous portion, of the 



Ureter 



-Orifice of ureter 

 Trigonum vesicae 



Uvula vesicse 



- Crista urethralis 



Opening of ejaculatory duct' 



- Utriculus prostaticus 



Bulbo-urethral gland 



Membranous urethra 



Opening of duct of bulbo- 

 urethral gland 



-Crus penis 



Corpus cavernosum penis (cut) 



1026. DISSECTION SHOWING THE TRIGONUM VESIC.E AKD THE POSTERIOR WALL OB FLOOR OF THE 

 FRETHRA IN ITS PROSTATIC, MEMBRANOUS, AND THE PROXIMAL PART OF ITS CAVERNOUS SUBDIVISIONS. 



The canal has been opened up by removing its anterior and upper wail. 



urethra leads downwards and forwards from the apex of the prostate to the 

 bulbus urethrse, and is the shortest and narrowest of the three subdivisions of the 

 canal, its length being somewhat less than half an inch. It begins at the superior 

 fascia of the urogenital diaphragm, a layer of pelvic fascia which lies above the 

 sphincter urethras membranacese muscle. Here it is continuous with the prostatic 

 portion of the urethra. It ends, having pierced the inferior fascia of the uro- 

 genital diaphragm, by becoming continuous with the cavernous portion of the 

 urethra. Placed in front of the anal canal, it lies about one inch behind and below 

 the arcuate ligament of the pubis (O.T. sub-pubic ligament). It is surrounded by 

 fibres of the sphincter urethras membranacese muscle, and behind it, on each side of 

 the median plane, lies the bulbo-urethral gland. The posterior part of the bulbus 



