HYPOGASTRIC AND PELVIC PLEXUSES. 703 



distinct ganglia. At the lower end it divides into two parts, which are 

 directed forwards, one to each side of the pelvic viscera, and form the pelvic 

 plexuses. 



PELVIC PLEXUS. 



The pelvic or inferior hypogastric plexuses, one on each side, are placed in 

 the lower part of the pelvic cavity by the side of the rectum, and of the 

 vagina in the female. The nerves, prolonged from the hypogastric plexus, 

 enter into repeated communications as they descend, and form at the points 

 of connection small knots, which contain a little gangliouic matter. After 

 descending some way, they become united with branches of the spinal 

 nerves, as well as with a few offsets of the sacral ganglia, and the union of 

 all constitutes the pelvic plexus. The spinal branches, which enter into 

 the plexus, are furnished from the third and fourth sacral nerves, especially 

 the third ; and filaments are likewise added from the first and second 

 sacral nerves. Small ganglia are formed at the places of union of the spinal 

 nerves, as well as elsewhere in the plexus (plexus gangliosus Tiedemann). 



From the plexus so constituted numerous nerves are distributed to the 

 pelvic viscera. They correspond with the branches of the internal iliac 

 artery, and vary with the sex ; thus, besides haemorrhoidal and vesical 

 nerves, which are common to both sexes, there are nerves special to 

 each : namely in the male, for the prostate, vesicula seminalis, and vas 

 deferens ; in the female, for the vagina, uterus, ovary, and Fallopian tube. 



The nerves distributed to the urinary bladder and the vagina contain a 

 larger proportion of spinal nerves than those furnished to the other pelvic 

 viscera. 



INFERIOR ILEMORRHOIDAL NERVES. These slender nerves proceed 

 from the back part of the pelvic plexus. They join with the nerves 

 (superior hsemorrhoidal) which descend with the inferior mesenteric artery, 

 and penetrate the coats of the rectum. 



VESICAL PLEXUS. The nerves of the urinary bladder are very numerous. 

 They are directed from the anterior part of the pelvic plexus to the side 

 and lower part of the bladder. At first, these nerves accompany the vesical 

 blood-vessels, but afterwards they leave the vessels, and subdivide into 

 minute branches before perforating the muscular coat of the organ. 

 Secondary plexuses are given in the male to the ras deferens and the 

 vesicula seminalis. 



The nerves of the vas deferens ramify round that tube, and communicate 

 in the spermatic cord with the nerves of the spermatic plexus. Those 

 furnished to the vesicula seminalis form an interlacement on the vesicula, 

 and some branches penetrate its substance. Other filaments from the 

 prostatic nerves reach the same structure. 



PROSTATIC PLEXUS. The nerves of this plexus are of considerable size, 

 and pass onwards between the prostate gland and the levator ani. Some are 

 furnished to the prostate and to the vesicula seminalis ; and the plexus is 

 then continued forwards to supply the erectile substance of the penis, where 

 its nerves are named " cavernous." 



Cavernous nerves of the penis. These are very slender, and difficult to 

 dissect. Continuing from, the prostatic plexus they pass onwards, beneath 

 the arch of the pubes, and through the muscular structure connected with 

 the membranous part of the urethra, to the dorsum of the penis. At ths 



