568 



MANUAL OF HISTOLOGY. 



structure. The description just given, however, refers more particularly to 

 the corpp. cav. penis. These are separated from one another anteriorly by 

 an imperfect partition. But, besides these, there is another cavernous 

 body, the bulb of the urethra, quite distinct from them, and remarkable for 

 having a thinner envelope, more delicate trabeculse, smaller receptacula, 

 and a larger proportion of elastic fibres. The interstices in the spongy 

 tissue of the glam are even narrower still. 



The reservoirs just mentioned are constantly filled with blood, but 

 become overcharged with the same at intervals, effecting that change in 

 the male organ known as erection. 



In order to understand this phenomenon clearly, it will be necessary to 

 review first of all the whole arrangement of vessels and circulation of the 

 cavernous organs. In doing this we shall adhere to the description given 

 in a very excellent work by Langer. 



The corpora cavernosa of the penis only receive a few inconsiderable 

 twigs from the dorsal artery ; they are chiefly supplied by the artericv 

 profundce which run close to the septum. These are enclosed in a sheath 



connected with the cavernous 

 cellular network, and give off 

 gradually numerous anastomos- 

 ing twigs to the cavernous sub- 

 stance which run along within 

 the trabeculae, and take a tor- 

 tuous course in the quiescent 

 state of the organ. 



The modes in which these 

 vessels merge into the cavities 

 of the venous spongy tissue are 

 several. 



In the first place, they de- 

 crease rapidly in diameter 

 towards the surface of the 

 corpora cavernosa, and more 

 so still in the vicinity of the 

 septum. Here we find true 

 capillary networks of some- 

 what large-sized tubes at the 

 point of transition. These con- 

 stitute, as Langer expresses it, 

 the "superficial cortical net- 

 work," and (fig. 551, 1, a) com- 

 municate with a "deeper sys- 

 tem of wide venous canals" 

 (b), " the deep cortical net- 

 work." 



An immediate transition of 

 fine arterial twigs (2, a) into 

 these latter is also to be seen, however, which explains the rapid occur- 

 rence of turgidity in the peripheral system of lacunae. 



Direct communication of terminal arterial twigs takes place also with 

 the deeper venous receptacles of the interior, a remarkable funnel-shaped 

 opening being evident at the point of transition (" Zap/en "). 



The trabeculae of the interior of the corpora cavernosa contain also 



Fig. 551. From the peripheral portion of the corpus 

 cavernosum penis, under low magnifying power. 1. a, 

 network, known as the superficial ; 6, the deep. 2. Con- 

 nection of arterial twigs (a) with the canals of the 

 deeper cortical network (copied after Langer). 



