1374 HUMAN ANATOMY. 



distributed to the descending and sigmoid colons and to the upper portion of the 

 rectum. 



The hypogastric plexus (plexus hypogastricus) (Fig. 1140), the continuation 

 of the aortic, hes on the posterior wall of the pelvis in the angle between the 

 common iliac arteries, and enclosed in a firm investment of fibrous tissue. In 

 addition to the fibres derived from the aortic plexus, others are contributed by 

 the lumbar ganglia, and the resulting intricate interlacement, in which there are 

 no ganglia, constitutes the hypogastric plexus. It supplies the pelvic contents 

 and at its lower end divides into the two pelvic plexuses. 



The pelvic plexuses (plexus hypogastric! inferiores), (Fig. 1140) the terminal 

 divisions of the hypogastric, are situated lateral to the rectum and to the vagina 

 in the female. They comprise fibres derived from the hypogastric plexus and from 

 the upper part of the sacral portion of the gangliated cord, aided by the visceral 

 branches of the pudendal plexus, all of these forming an elaborate net-work, in which 

 are dotted numerous small ganglia. The completed structure follows the course 

 of the internal iliac artery, around whose branches it sends derivatives for the 

 supply of the pelvic contents. 



The hemorrhoidal plexus (plexus hemorrhoidalis medius) arises from the 

 upper portion of the pelvic plexus and after inosculating with the superior 

 hemorrhoidal branches (nn. hemorrhoidales superiores) of the inferior mesenteric 

 plexus, are distributed to the rectum. 



The vesical plexus (plexus vesicalis) consists of branches of the pelvic which 

 accompany the vesical arteries to the lateral and inferior portions of the bladder, 

 after reaching which they leave the vessels and split into small twigs for the supply 

 of the bladder, some filaments going to the ureter, the vas deferens and the seminal 

 vesicle. 



The prostatic plexus (plexus prostaticus) comprises a number of nerves of con- 

 siderable size and is situated between the lateral aspect of the prostate gland and 

 the mesial surface of the levator ani muscle. After furnishing twigs to the prostatic 

 urethra, the neck of the bladder and the seminal vesicle, it continues forward as the 

 cavernous plexus. 



The cavernous plexus (plexus cavernosus penis) extends forward through the 

 triangular ligament and the compressor urethrae muscle to the dorsum of the base of 

 the penis, where it receives some communicating filaments from the pudic nerve. 

 After supplying branches to the apex of the prostate gland and the membranous 

 urethra, the plexus terminates by breaking up into (i) the small and (2) large 

 cavernous nerves of the penis. 



1. The small cavernous nerves (nn. cavernosi penis rainores) pierce the 

 fibrous envelope of the crus penis and end in filaments which supply the erectile 

 tissue of the corpus cavernosum. 



2. The large cavernous nerve (n. cavernosus penis major), consisting mainly 

 of medullated fibres, passes directly along the dorsum of the penis, giving off fila- 

 ments which enter the substance of the corpus cavernosum. At about the middle of 

 the body of the penis it inosculates with the dorsal nerve of the penis, both of these 

 nerves sending twigs to the corpus spongiosum. 



The utero-vaginal plexus (plexus uterovaginalis) corresponds to the prostatic 

 plexus of the male and consists of two portions : (j) the uterine plexus and (2) the 

 vagiyial plexus. 



1. The uterine plexus (plexus utcrinus) is derived from the pelvic plexus and is 

 supplemented in its distribution by the visceral branches from the pudendal plexus. 

 These fibres accompany the uterine vessels along the side of the uterus, most of them 

 entering the cervix and the lower portion of the body of the uterus. They inoscu- 

 late with fibres from the ovarian plexus and in their meshes are found many small 

 ganglia, a collection of which is located near the cervix uteri and is called the gang- 

 lion cervicale. 



2. The vaginal plexus (plexus vaginalis) arises from the lower part of the 

 pelvic and comprises mainly fibres derived from the visceral branches of the puden- 

 dal plexus. It supplies the vagina and the virethra and continues forward as the 

 cavernous plexus of the clitoris (plexus cavernosus clitoridis). 



