814 FEMALE ORGANS OF GENERATION. 



A thin layer of spongy, erectile tissue, intermixed with, much elastic tissue, 

 lies immediately beneath the mucous coat. 



The mucous coat is pale, continuous, externally with that of the vulva, and 

 internally with that of the bladder.. It is thrown into longitudinal folds, one 

 of which, placed along the floor of the canal-, resembles the verumontanum in 

 the male urethra. It is lined by laminated epithelium, which becomes sphe- 

 roidal at the bladder. Its external orifice is surrounded by a few mucous 

 follicles. 



The urethra, from not being surrounded by dense resisting structures, as in 

 the male, admits of considerable dilatation, which enables the surgeon to remove 

 with considerable facility calculi, or other foreign bodies, from the cavity of 

 the bladder. 



THE RECTUM. 



The Rectum is more capacious, and less curved in the female, than in the male. 



The first portion extends from the left sacro-iliac symphysis to the middle of 

 the sacrum. Its connections are similar to those in the male. 



The second portion extends to the tip of the coccyx. It is covered in front by 

 the peritoneum, but only for a short distance, at its upper part, and is in rela- 

 tion with the posterior wall of the vagina. 



The third portion curves backwards, from the vagina to the anus, leaving a 

 space which corresponds on the surface of the body to the perineum. Its ex- 

 tremity is surrounded by the Sphincter muscles, and its sides are supported by 

 the Levatores Ani. 



THE VAGINA. 



The Vagina is a membranous canal, extending from the vulva to the uterus. 

 It is situated in the cavity of the pelvis, behind the bladder, and in front of 

 the rectum. Its direction is curved forwards and downwards, following at first 

 the line of the axis of the cavity of the pelvis, and afterwards that of the out- 

 let. It is cylindrical in shape, flattened, from before backwards, and its walls 

 are ordinarily in contact with each other. Its length is about four inches along 

 its anterior wall, and between five and six inches along its posterior wall. It is 

 constricted at its commencement, and becomes dilated near its uterine extre- 

 mity ; it surrounds the vaginal portion of the cervix uteri, a short distance 

 from the os, and its attachment extends higher up on the posterior than on the 

 anterior wall of the uterus. 



Relations. Its anterior surface is concave, and in relation with the base of the 

 bladder, and with the urethra. Its posterior surface is convex, and connected to 

 the anterior wall of the rectum, for the lower three-fourths of its extent, tho 

 upper fourth being separated from that tube by the recto-uterine fold of peri- 

 toneum, which forms a cul-de-sac between the vagina and rectum. Its sides give 

 attachment superiorly to the broad ligaments, and inferiorly to the Levatores 

 Ani muscles and recto-vesical fascia. 



Structure. The vagina consists of an external, or muscular coat, a layer of 

 erectile tissue, and an internal mucous lining. 



The muscular coat consists of longitudinal fibres, which surround the vagina, 

 and are continuous with the superficial muscular fibres of the uterus. The 

 strongest fasciculi are those attached to the recto-vesical fascia on each side. 



The erectile tissue is inclosed between two layers of fibrous membrane ; it is 

 more abundant at the lower than at the upper part of the vagina. 



The mucous membrane is continuous, above, with that lining the uterus, and 

 below, with the integument covering the labia majora. Its inner surface pre- 

 sents, along the anterior and posterior walls, a longitudinal ridge, or raphe, 

 called the columns of the vagina, and numerous transverse ridges, or rugae, ex- 

 tending outwards from the raphe on each side. These ruga3 are most distinct 

 near the orifice of the vagina, especially in females before parturition. They 



