658 THE PENIS. 



tween them two grooves, the one superior, occupied "by 

 the dorsal vessels and nerves ; the other, inferior, contain- 

 ing the urethra. Each corpus consists of a white, very 

 strong, fibrous, and elastic membrane, consisting mostly of 

 longitudinal fasciculi closely interlacing each other, though 

 an internal layer of circular fibres, as continuous with the 

 septum, is also seen. From the inferior groove, a number 

 of radiating fibrous bands are seen crossing the cavities of 

 the corpora to be inserted in the inner walls of this fibrous 

 tunic ; these cords are called trabeculce, and are believed to 

 strengthen the organ as well as to limit its distension. The 

 interior of each corpus is occupied by a soft, cellulo-vascu- 

 lar, or erectile tissue, presenting a spongy appearance, or a 

 multitude of cells, all of which communicate freely with 

 each other and with the veins, and consist, says Dr. Morton, 

 of an intertexture of veins closely woven together, so as to 

 present the appearance of cells, which veins or venous plex- 

 uses are supported and separated by the trabeculse. 



The corpus spongiosum surrounds the urethra, and ex- 

 extends from between the crura about an inch behind 

 their junction to the extremity of the penis. Its poste- 

 rior extremity is called the bulb its anterior the glans 

 penis. The base of the glans presents a projection or 

 shoulder, termed the corona glandis, and behind this is 

 noticed a contraction called the neck. 



The structure of the corpus spongiosum resembles the 

 cavernosum, except that its external aponeurotic coat is 

 much thinner, and its interior spongy erectile tissue much 

 finer and more delicate. There is no direct communication 

 between the corpora cavernosa and spongiosum, though a 

 fine injection from the pudic artery will occasionally suc- 

 ceed in injecting both at the same time. 



The urethra (Fig. 210) is a membranous canal situated 

 along the inferior groove of the corpora cavernosa, and ex- 

 tending from the neck of the bladder to the extremity of 

 the penis. The course of this canal from the neck of the 

 "bladder is first forward and downward, covered by the 

 prostate gland, and called the prostatic portion. It then 



