PELVIS 6 4y 



distension of the cavities of certain tubular glands which 

 lie in the mucous membrane. 



The Coats of the Vagina. The vagina possesses an 

 external muscular coat, an internal mucous coat, and an 

 intermediate layer of erectile tissue. The muscular coat is 

 formed of unstriped muscle fibres arranged in two layers, an 

 external longitudinal layer and an internal circular layer, 

 of which the former is much the stronger. The mucous 

 membrane presents two well-marked median longitudinal 

 folds, one on the anterior, and one on the posterior wall. 

 These are termed the columncz rugarum, and from each side 

 they send off numerous transverse ridges, which are arranged 

 so that those of the anterior wall fit in between those on the 

 posterior wall. The folds are best marked near the vaginal 

 orifice, and are absent at the upper part of the canal. The 

 intermediate layer of erectile tissue is thin. 



Structure of the Uterine Tubes. Each uterine tube 

 has an external serous, an intermediate muscular, and an 

 internal mucous lining coat. The serous coat is the peritoneal 

 covering formed by the layers of the broad ligament. The 

 muscular coat consists of an external longitudinal and an 

 internal circular layer of unstriped muscle fibres. The tube 

 is so narrow in the region of the isthmus that the mucous 

 membrane in that region can only be satisfactorily examined 

 in sections and with the aid of the microscope, but the 

 ampulla is easily opened, and when this has been done the 

 dissector will recognise that the mucous membrane is arranged 

 in longitudinal folds. To obtain a proper idea of the 

 fimbriae the tube should be immersed in water, when they 

 will float out and separate from each other. 



The Coats of the Rectum and Anal Canal. The coats 

 of these portions of the intestinal canal are identical in both 

 sexes. The student should refer, therefore, to p. 609, where 

 the walls of the male rectum and anal canal are described. 



Dissection. When the dissector has completed his study of the structure 

 of the pelvic viscera he should return to the investigation of the pelvic 

 spinal nerve plexuses, and the sympathetic cord, and the coccygeal body 

 (see p. 608). After he has satisfied himself regarding the formation and 

 distribution of the plexuses, and the position and connections of the 

 sympathetic cord, he should study the pelvic diaphragm. 



The sacro-pudendal and the coccygeal nerve plexuses are 

 the same in both sexes, and the description of their constitu- 

 tion and relations will be found on p. 605. 



