544 VAGINA UTERUS. 



variable ; but it is always longer upon the posterior than upon the 

 anterior wall, the form^pbeing usually about five or six inches in 

 length, and the latter four or five. It is inserted into the cervix of 

 the uterus, which projects into the upper extremity of the canal. 



In Structure the vagina is composed of a mucous lining, a layer 

 of erectile tissue, and an external tunic of a celMo-fibrous structure, 

 resembling the dartos of the scrotum. The upper fourth of the 

 posterior wall of the vagina is covered, on its pelvic surface, by the 

 peritoneum ; while in front the peritoneum is reflected from the 

 upper part of the cervix of the uterus to the posterior surface of the 

 bladder. On each side it gives attachment superiorly to the broad 

 ligaments of the uterus ; and inferiorly to the pelvic fascia, and to 

 the levatores ani. 



The Mucous membrane presents a number of transverse papillce 

 or ruga upon its upper and lower surfaces, which extend outwards 

 on each side from a middle raphe. The transverse papillae and 

 raphe are more apparent upon the upper than upon the lower sur- 

 face, and the two raphe are called the columns of the vagina. The 

 mucous membrane is covered by a thin cuticular epithelium, which 

 is continued from the labia, and terminates by a fringed border at 

 about the middle of the cervix uteri. 



The Middle or erectile layer consists of erectile tissue enclosed 

 between two layers of fibrous membrane ; this layer is thickest near 

 the commencement of the vagina, and becomes gradually thinner 

 as it approaches the uterus. 



The External, or dartoid layer of the vagina, serves to connect 

 it to the surrounding viscera. Thus, it is very closely adherent to 

 the under surface of the bladder, and drags that organ down with 

 it in prolapsus uteri. To the rectum it is less closely connected, and 

 that intestine is therefore less frequently affected in prolapsus. 



UTERUS. 



The Uterus is a flattened organ of a pyriform shape, having the 

 base directed upwards and forwards, and the apex downwards and 

 backwards in the line of the axis of the inlet of the pelvis, and 

 forming a considerable angle with the course of the vagina. It is 

 convex on its posterior surface, and somewhat flattened upon its 

 anterior aspect. In the uhimpregnated state it is about three inches 

 in length, two in breadth across its broadest part, and one in thick- 

 ness, and is divided into fundus, body, cervix, and os uteri. At the 

 period of puberty the uterus weighs about one ounce and a half ; 

 after parturition from two to three ounces ; and at the ninth month 

 of utero-gestation from two to four pounds. 



The Fundus and body are enclosed in a duplicature of peritoneum, 

 which is connected with the two sides of the pelvis, and forms a 

 transverse septum between the bladder and rectum. The folds 

 formed by this duplicature of peritoneum on either side of the 

 organ are the broad ligaments of the uterus. The cervix is the 



