982 FEMALE ORGANS OF GENERATION. 



columns. These columns and rugae are most evident near the entrance of 

 the vagina and on the anterior surface, and gradually become less marked, 

 and disappear towards its upper end. 



Structure and connections. The walls of the vagina are thickest in front, 

 in the vicinity of the urethra, which indeed may be said to be imbedded 

 in the anterior wall of the vaginal passage ; in other situations they are 

 thinner. The vagina is firmly connected by areolar tissue to the neck of 

 the bladder, and only loosely to the rectum and levatores ani muscles ; at 

 the upper end, for about a fourth part of its length, it receives a covering 

 behind from the peritoneum, which descends in the form of a cul-de-sac 

 thus far between the vagina and the rectum. 



Externally the vagina presents a coat of dense areolar tissue, and be- 

 neath this its walls are composed of unstriped muscle, which is not distinctly 

 separable into strata, but is composed chiefly of fibres internally circular 

 and externally longitudinal. Round the tube a layer of loose erectile 

 tissue is found, which is most marked at the lower part. 



At its lower end, the vagina is embraced by muscular fibres, which con- 

 stitute the sphincter vagince, already described (p. 266). 



The mucous membrane, besides the columns and rugae, is provided with 

 conical and filiform papillae, numerous muciparous glands and follicles, 

 especially in its upper smoother portion and round the cervix uteri. 

 This membrane, which is continuous with that of the uterus, is covered 

 with a squamous epithelium. 



The vagina is largely supplied with vessels and nerves. The arteries. are derived 

 from branches of the internal iliac, viz., the vaginal, internal pudic, vesical, and 

 uterine (pp. 422, 428). The veins correspond ; but they first surround the vagina 

 with numerous branches, and form at each side a plexus named the vaginal plexus. 

 The nerves are derived from the hypogastric plexus of the sympathetic, and from the 

 fourth sacral and pudic nerves of the spinal system ; the former are traceable to the 

 erectile tissue (p. 704). 



THE UTERUS. 



The uterus, womb, or matrix, is a hollow organ, with very thick walls, 

 which is intended to receive the ovum, retain and support it during the 

 development of the fcetus, and expel it at the time of parturition. The 

 ova, discharged from the ovaries, reach the uterus by the Fallopian tubes, 

 which open, one at each side, into the upper part of that organ. During 

 pregnancy, the uterus undergoes a great enlargement in size and capacity, 

 as well as other important changes. In the fully developed virgin condi- 

 tion, which is that to which the following description applies, it is a pear- 

 shaped body, flattened from before backwards, situated in the cavity of the 

 pelvis, between the bladder and rectum, with its lower extremity projecting 

 into the upper end of the vagina. It does not reach above the brim of the 

 pelvis. Its upper end is turned upwards and forwards, whilst the lower is 

 in the opposite direction ; so that its position corresponds with that of the 

 axis of the inlet of the pelvis, and forms an angle or curve with the axis of 

 the vagina, which corresponds with that of the outlet of the cavity. The 

 uterus projects, as it were, upwards into a fold of the peritoneum, by 

 which it is covered behind and above, and also in front, except for a short 

 distance towards the lower end, where it is connected with the base of the 

 bladder. Its free surface is in contact with the other pelvic viscera, some 

 convolutions of the small intestine usually lying upon and behind it. 

 From its two sides the peritoneum is reflected iu the form of a broad 



