958 MALE ORGANS OF GENERATION. 



nerves. The muscular tissue is much more abundant in the penis of some 

 animals than in man. 



The iutertrabecular spaces form a labyrinth of intercommunicating 

 venous areolse divided by the trabecular tissue. The spaces of the two 

 sides communicate freely through the septum, especially in front. They 

 return their blood partly by a series of branches which escape between 

 the corpora cavernosa and the corpus spongiosum, and which, accompanied 

 by veins from the latter, mount on the sides of the penis to the vena 

 dorsalis, partly by short veins issuing at the upper surface, and imme- 

 diately joining the dorsal vein, but principally by veins passing out near 

 the root of the penis and joining the prostatic plexus and pudendal veins. 

 According to Kobelt, there are also communications with the cutaneous 

 veins on the abdomen. 



The arteries of the corpora cavernosa are branches of the ptidic artery. 

 The proper cavernous arteries (profundse penis), right and left, supply them 

 chiefly ; but the dorsal artery of the penis also sends twigs through the 

 fibrous sheath, along the upper surface, especially in the fore part of the 

 penis. Within the cavernous tissue, the numerous branches of arteries are 

 supported by the trabeculsB, in the middle of which they run, and terminate 

 in two modes ; some of them subdividing into branches of capillary minute- 

 ness which open into the intertrabecular spaces ; while others form tendril- 

 like twigs which project into the spaces, and end in curling dilated extre- 

 mities the helicine arteries of J. Muller, sometimes singly and sometimes 

 in tufts. The extremity of each curled dilatation would appear to be bound 

 down by a small fibrous band, which according to Henle is usually solid, 

 but is said by Kolliker to contain a capillary continuation of the blood- 

 Fig. 673. Fig. 673. ONE OP THE TUFTS CONTAINING A HELICINE ARTERY 



MORE HIGHLY MAGNIFIED (from J. Muller). 



The tuft is represented as projecting into the cavity of a 

 vein. 



vessel. The helicine arteries are most abundant in the 

 posterior part of the corpora cavernosa, and are found 

 in the corresponding part of the corpus spongiosum 

 also ; but they have not been seen in the glans penis. 



They are most distinct in man, but are not constant in animals, so that, 

 whatever may be their use, they do not appear to be essential to the process 

 of erection. 



CORPUS SPONGIOSUM. 



The corpus spongiosum urethrce commences in front of the triangular 

 ligament of the perineum, between the diverging crura of the corpora 

 cavernosa, and somewhat behind their point of junction, by an enlarged and 

 rounded extremity named the bulb. It extends forwards as a cylindrical, 

 or slightly tapering body, lodged in the groove on the under side of the 

 united cavernous bodies, as far as their blunt anterior extremity, over 

 which it expands so as to form the glans penis already described. 



The posterior bulbous extremity, or bulb of the urethra, varies in size in 

 different subjects. It receives an investment from the triangular ligament 

 in which it rests, and is embraced by the accelerator urinse, or bulbo- 

 cavernosus muscle. The posterior extremity of the bulb exhibits, more or 



