878 THE NERVOUS SYSTEM. 



The Pelvic Plexus. 



The Pelvic Plexus (sometimes called inferior hypogastric) supplies the viscera 

 of the pelvic cavity, is situated at the side of the rectum and bladder in the male, 

 and at the side of the rectum, vagina, and bladder in the female. It is formed by 

 a continuation of the hypogastric plexus, by branches from the second, third, and 

 fourth sacral nerves, and by a few filaments from the first two sacral ganglia. At 

 the point of junction of these nerves small ganglia are found. From this plexus 

 numerous branches are distributed to all the viscera of the pelvis. They accom- 

 pany the branches of the internal iliac artery. 



The inferior hsemorrhoidal plexus arises from the back part of the pelvic 

 plexus. It supplies the rectum, joining with branches of the superior hsemor- 

 rhoidal plexus. 



The vesical plexus arises from the fore part of the pelvic plexus. The nerves 

 composing it are numerous, and contain a large proportion of spinal nerve-fibres. 

 They accompany the vesical arteries, and are distributed at the side and base of 

 the bladder. Numerous filaments also pass to the vesiculae seminales and vas 

 deferens ; those accompanying the vas deferens join, on the spermatic cord, with 

 branches from the spermatic plexus. 



The prostatic plexus is continued from the lower part of the pelvic plexus. 

 The nerves composing it are of large size. They are distributed to the pros- 

 tate gland, vesicuke seminales, and erectile structure of the penis. The nerves 

 supplying the erectile structure of the penis consist of two sets, the small and 

 large cavernous nerves. They are slender filaments, which arise from the fore 

 part of the prostatic plexus, and, after joining with branches from the internal 

 pudic nerve, pass forward beneath the pubic arch. 



The small cavernous nerves perforate the fibrous covering of the penis near its 

 roots. 



The large cavernous nerve passes forward along the dorsum of the penis, 

 joins with the dorsal branch of the pudic nerve, and is distributed to the corpus 

 cavernosum and spongiosum. 



The vaginal plexus arises from the lower part of the pelvic plexus. It is lost 

 on the walls of the vagina, being distributed to the erectile tissue at its anterior 

 part and to the mucous membrane. The nerves composing this plexus contain, 

 like the vesical, a large proportion of spinal nerve-fibres. 



The uterine plexus arises from the upper part of the pelvic plexus above the 

 point where the branches from the sacral nerves join the plexus. Its branches 

 accompany the uterine arteries to the side of the organ between the layers of the 

 broad ligament, and are distributed to the cervix and lower part of the body of the 

 uterus, penetrating its substance. 



Other filaments pass separately to the body of the uterus and Fallopian tube. 



Branches from the plexus accompany the uterine arteries into the substance 

 of the uterus. Upon these filaments ganglionic enlargements are found. 



