THE GENITOURINARY APPARATUS. 271 



From these spaces the veins begin; some wind around the 

 side of the organ to the dorsal vein,, while others pass under 

 the pubis to join the prostatic plexus. 



The lymphatics are numerous; the superficial join the 

 inguinal glands, the deep join the lymphatic plexus about the 

 prostate and other deep lymphatics of the pelvis. 



THE MALE URETHRA is the common canal for the emission 

 of semen and urine, extending from the neck of the bladder to 

 the meatus urinarius. It is from eight to nine inches in length, 

 and consists of three portions the prostatic, membranous, and 

 spongy. 



The prostatic portion extends from the neck of the bladder 

 to the anterior border (apex) of the prostate gland. It is one 

 and one-quarter inches in length, and is the widest and most 

 dilatable part. 



Its floor is raised, and presents : 



Veru inmilunnm, or caput gallinaginis, an elevated ridge; 



Prostatic sinus, on each side of the veru montanum ; 



Orifices of the prostatic ducts, in the floor of the prostatic 

 sinuses ; 



Sinus pocularis, a depression in the median line in front of 

 the veru montanum, presenting the slit-like open ings of the 

 ejaculate ry ducts. This cnl-ilr-xac is one-quarter of an inch in 

 length. It is homologous with the uterus, and has received the 

 name of utricle, or ///rn/x masculinus. 



The membranous portion is about three-quarters of an inch 

 in length, extending from the apex of the prostate gland to the 

 corpus spongiosum above and in advance of the bulb. It passes 

 out of the pelvis beneath the symphysis pubis, traversing the 

 1 r i angular ligament. It is the least dilatable portion and has 

 four coats: 



Fibrous, continuous with both layers of the triangular liga- 

 ment ; erectile, continuous with that of the spongy body ; an un- 

 striated imisi-ular layer, and a mucous coat. 



The spongy portion extends from the membranous portion 

 through the corpus spongiosum to the meatus urinarius on the 

 summit of the glans. 



The portion within the bulb has received the name of 

 bulbous portion of the urethra. The spongy portion diminishes 

 gradually in size to near the orifice, where it suddenly dilates 

 into the fossa navicularis, contracting again at the meatus, the 

 narrowest part of the urethra. 



The mucous membrane is provided with columnar epithe- 

 lium, except near the meatus, where it is tessellated, a fibre-elastic 

 submucous layer with unstriated muscular fibres, and numerous 



18 



