PELVIC PLEXUS. 601 



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

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

 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 to the side and base of 

 the bladder. Numerous filaments also pass to the vesiculas 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 prostate 

 gland, vesiculae seminales, and erectile structure of the penis. The nerves sup- 

 plying 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 forwards beneath the pubic arch. 



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

 its root. 



The large cavernous nerve passes forwards along the dorsum of the penis, joins 

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

 nosum and corpus 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 nerves arise from the lower part of the hypogastric plexus, above 

 the point where the branches from the sacral nerves join the pelvic plexus. They 

 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 hypogastric plexus accompany the uterine arteries into the 

 substance of the uterus. Upon these filaments ganglionic enlargements are found. 1 



1 Much difference of opinion still exists as to whether the uterine nerves enlarge during preg- 

 nancy. Dr. Eobert Lee states, as the result of a series of elaborate investigations, that the 

 nerves and ganglia supplying the uterus become greatly enlarged during gestation, thus confirm- 

 ing the observations previously made by William Hunter, and Tiedemann. Dr. Snow Beck, on 

 the other hand, asserts that the nerves do not alter in size during pregnancy. 



For a detailed account of this subject, the reader should refer to "The Anatomy of the Nerves 

 of the Uterus," by Robert Lee, M. D., 1841 ; to two papers by the same author in the Phil. 

 Trans., for 1842 ; and to Dr. Snow Beck's paper, "On the Nerves of the Uterus," in the Phil. 

 Trans., for 1846. 



