506 ABDOMEN 



THE VISCERAL NERVES OF THE PELVIS. 



Very little requires to be added to what has already been 

 said about the visceral nerve plexuses (p. 464). There is no 

 prostatic plexus ; but a vaginal plexus, an ovarian plexus, and a 

 uterine plexus are present in addition to those mentioned 

 in the description of the male pelvis. 



The uterine plexus proceeds from the pelvic plexus. It 

 ascends between the layers of the broad ligament, along the 

 uterine artery, and is distributed to both aspects of the uterus. 



The vaginal plexus is also an offset from the pelvic plexus, 

 and the nerves which compose it are derived mainly from 

 the visceral branches which enter the pelvic plexus from 

 the third and fourth sacral nerves. 



The ovarian plexus is derived from the aortic and renal 

 plexuses. It accompanies the artery of the same name, and is 

 distributed to the ovary. 



Dissection. When the blood-vessels and the visceral nerve 

 plexuses have been examined, the pelvic viscera should be re- 

 moved. The vessels and nerves passing to them must be cut ; 

 the visceral layer of pelvic fascia on the upper surface of the 

 levator ani must be divided, from before backwards, and stripped 

 medially from the upper surface of the muscle. Finally, the 

 rectum must be separated from the upper end of the anal canal, 

 and then the viscera can be removed. When that has been done 

 the structure of the walls of the viscera should be studied. 



Structure of the Uterus. The uterus possesses three 

 well-marked coats a serous or peritoneal, a muscular and a 

 mucous. The serous covering has already been fully studied 

 (p. 495). The muscular part of the wall constitutes its chief 

 bulk. It is composed of involuntary muscular tissue, with a 

 considerable admixture of areolar tissue. It is not equally 

 thick throughout, and is relatively thin towards the angles 

 or points where the uterine tubes open into the uterus. 



The mucous membrane which lines the cavity is not of 

 uniform appearance. In the -body of the uterus it is smooth 

 and closely bound to the adjacent muscle. In the cervix 

 it presents a striking arrangement, which from its appearance 

 has been termed the arbor vita. The arbor vitae consists of 

 a series of prominent folds or rugae, called plica palmata, 

 arranged in a definite manner. There is a median fold on the 

 anterior and another on the posterior wall of the canal. 



