PENIS. 



917 



runs forwards by the side of the septum pec- 

 tiniforme, distributing many branches in its 

 course, which ramify in the parietes of the 

 venous canals. 



The arteria dorsalis penis may be regarded 

 as the continuation of the internal pudic, after 

 the latter has given off" the arteria corporis 

 cavernosi. It commences opposite the junction 

 of the crura penis, and piercing the anterior 

 layer of the deep perineal fascia, ascends to 

 the groove upon the dorsum penis. In this 

 groove it runs forwards to the base of the glans, 

 where it divides into several branches, which 

 enter the substance of that body and are distri- 

 buted to its structure. The arteria dorsalis is 

 separated from its fellow by the dorsal vein, 

 and gives off numerous branches in its course 

 to the fibrous structure of the penis and inte- 

 gument. 



The veins of the penis correspond with the 

 arteries which they accompany in their efferent 

 course. The ven<e corporis bulbosi and venas. 

 corporis cavernosi, issuing respectively from 

 the bulb and crura penis, take the course of 

 the internal pudic artery, and constitute the 

 internal pudic veins. At the root of the penis 

 these veins communicate with the dorsal vein. 



The dorsal vein commences by numerous 

 large branches, the chief of which issue from 

 the base of the glans beneath the corona, and 

 form by their communications a considerable 

 plexus on the anterior part of the corpus caver- 

 nosum, the others being the veins of the prepuce 

 and integument. The union of these veins 

 constitutes two trunks of equal size, which, 

 after running side by side for a short distance, 

 unite and form the dorsal vein. The dorsal 

 vein in its course towards the root of the penis 

 passes beneath the aponeurosis of the erectores 

 muscles, together with the attachment of the 

 suspensory ligament, and after piercing the deep 

 perineal fascia, divides into several branches 

 which join the prostatic and vesical plexus. 

 It receives in its course several large branches 

 from the corpus spongiosum, which curve 

 around the corpus cavernosum in order to reach 

 it, and communicates at the root of the organ 

 with the deep veins of the penis. The dorsal 

 vein is situated in the middle line of the groove 

 of the dorsum penis, having its corresponding 

 artery at either side, and being covered in by 

 the fascia penis and conjoined aponeurosis of 

 the erectores penis muscles. It is this relation 

 to the fascia penis and aponeurosis of the 

 erectores that enables the latter to compress the 

 vein forcibly against the dense fibrous coat of 

 the corpus cavernosum, and thus intercept the 

 current of venous blood. 



The question of the ultimate arrangement 

 of the bloodvessels in the substance of the 

 penis leads to enquiry into the nature of erec- 

 tile tissue, a subject to which a separate article 

 has been devoted in the earlier pages of this 

 work, and to which I must now refer my 

 reader. From my own investigations into the 

 structure of this tissue in the corpus caverno- 

 sum and corpus spongiosum, I have come to 

 the conclusion that the arteries ramify and ter- 

 minate in capillaries as in other parts of the 



body, and that these latter very speedily be- 

 come dilated veins. In the distribution of the 

 veins the only peculiarity of this tissue exists ; 

 these by their tortuous windings form an in- 

 extricable plexus, which fills the whole area of 

 the fibrous tunics of the corpus cavernosum 

 and spongiosum, and constitutes their com- 

 ponent substance. In this plexiform aggre- 

 gation of veins, the walls of the vessels so 

 closely approach as to leave between them 

 only so much connecting tissue as serves for 

 the ramification of the arteries and nerves of 

 the organ, and for the passage of the fibrous 

 trabeculte and fibres of the contractile tissue. 

 It follows from this arrangement that the areae 

 of the veins bear a much greater proportion to 

 the bulk of the tissue than do the septa between 

 them, and, consequently, that if a section of 

 the corpus cavernosum be made, its parenchyma 

 will have the appearance of a cellular net- 

 work, an appearance that is rendered much 

 more striking when the penis has been inflated 

 and dried. It is obviously this appearance of 

 the parenchyma of the corpus cavernosum. 

 that has gained for it the character of being 

 composed of cells, and in truth, as far as the 

 plane of the section is concerned, the portions 

 of venous canals which open on the surface 

 have all the attributes of divided cells. Ac- 

 cording to the position of the veins at the point 

 of section, the cell in one spot is shallow and 

 small, in another it is lengthened, either in the 

 longitudinal or in the transverse direction of 

 the axis of the corpus cavernosum, and in a 

 third, again, the apparent cell is irregular in 

 form, from the conjunction at that point of two 

 or more veins. If, in the next place, we turn 

 our attention to the septa of the apparent cells, 

 we shall meet with spots in which from the 

 close assemblage of the veins the septum has 

 the appearance of a star giving off a number 

 of thin lines in a radiated direction to form 

 partitions between three, four, or five veins 

 which meet at that point. Now let us suppose 

 that this observation is being made on the 

 parenchyma of the corpus cavernosum, the 

 arteries of which have been previously injected 

 with fine injection. Where do we look for the 

 injected arteries ? Obviously in the septa, and 

 especially at that thicker portion of the septum 

 where several veins lie in contact. And what, 

 we may ask, is the probable appearance of the 

 arteries in that star-like point of septum which 

 I have described above ? I can answer this 

 question, from repeated observation. It is 

 that of a short trunk giving off' two, three, or 

 four small and short terminal branches, which 

 diverge in an oblique direction from the ex- 

 tremity of the small trunk, and terminate 

 abruptly at the cut margin of the septum. I 

 have seen the appearances here described many 

 times, sometimes better, sometimes less dis- 

 tinct, and more frequently as a bifid division 

 than another, and these I apprehend are the 

 urteritE helicincE of Miiller. Besides the pre- 

 ceding, the special characters of the arterite 

 helicinse are their projection in the form of a 

 tuft into a venous canal, and the curved, 

 swollen, and conical form of the small branches 



