THE PERINEUM, MALE. 417 



Nerve Supply. Dorsal nerve of the penis. 



Action. To compress the membranous urethra, which 

 it surrounds, expelling its contents (urine or semen). To 

 aid erection by compressing the emergent veins of the penis. 

 To compress Cowper's glands and so force out their secre- 

 tion. This may be independent of the emission of semen 

 or in connection with that act. 



Cowper's Glands. Diag. 28. 



These are two glands about as large as small peas, 

 situated between the two layers of the triangular ligament, 

 close to and behind the membranous urethra, and under 

 (above) the bulb of the penis. 



The duct of a gland is about an inch long. It pierces 

 the anterior layer of the triangular ligament, the corpus 

 spongiosum, and opens into the floor of the urethra (bul- 

 bous portion). 



DISSECTION. 



Carefully remove the compressor urethrse muscle and the nerve and 

 artery and their branches. 



Remove the hemorrhoidal vessels and nerves. 

 Section a portion of the gluteus maximus. 



The Posterior Layer of the Triangular Ligament. See 

 page 402. 



The Anal Fascia. See page 402. 



DISSECTION. 



Remove the posterior layer of the triangular ligament and the anal fascia 

 (which are continuous, as explained). 



Levator Ani. Fig. 83. 



Origin. From the inner surface of the body of the 

 pubis, from the angle between the obturator and recto- 

 vesical fascise the so-called " white line " and from the 

 inner surface of the spine of the ischium. 

 27 



