STRUCTURE OF THE UTERUS. 



547 



Fig. 243.f 



part, and one in thickness, and is divisible 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 sides of the pelvis, and forms a transverse 

 septum between the bladder and rectum. The folds formed by this du- 

 plicature of peritoneum on either side of the organ are the broad ligaments 

 of the uterus. The cervix is the lower portion of the organ ; it is distin- 

 guished from the body by a well-marked constriction ; around its circum- 

 ference is attached the upper end of the vagina, and at its extremity is an 

 opening which is nearly round in the virgin, and transverse after parturi- 

 tion, the os uteri, bounded before and behind by two labia ; the anterior 

 labium being the most thick, and the posterior somewhat the longest. 

 The opening of the os uteri is of considerable size, and is named the ori- 

 ficium uteri externum ; the canal then becomes narrowed, and at the 

 upper end of the cervix is constricted into a smaller opening, the orificium 

 internum.* At this point the canal of the cervix expands into the shallow 

 triangular cavity of the uterus, the infe- 

 rior angle corresponding with the ori- 

 ficium internum, and the two superior 

 angles, which are funnel-shaped, and re- 

 present the original bicornute condition 

 of the organ, with the commencement of 

 the Fallopian tubes. In the canal of the 

 cervix uteri are two or three longitudinal 

 folds, to which numerous oblique folds 

 converge so as to give the idea of 

 branches from the stem of a tree ; hence 

 this appearance has been denominated 

 the arbor vita uterina. Between these 

 folds, and around the os uteri, are nu- 

 merous mucous follicles. It is the closure 

 of the mouth of one of these follicles, and 

 the subsequent distention of the follicle 

 with its proper secretion, that occasions 

 those vesicular appearances, so often 

 noticed within the mouth and cervix of 

 the uterus, called the ovula ofNaboth. 



Structure. The uterus is composed 

 of three tunics : of an external or serous 

 coat, derived from the peritoneum, which constitutes the duplicatures on 

 each side of the organ called the broad ligaments ; of a middle or muscu- 

 lar coat, which gives thickness and bulk to the uterus ; and of an internal 

 or mucous membrane, which lines its interior, and is continuous on the one 

 hand with the mucous lining of the Fallopian tubes, and on the other with 

 that of the vagina. In the unimpregnated state the muscular coat is ex- 

 ceedingly condensed in texture, offers resistance to section with the scalpel, 



* The orificium internum is not unfrequently obliterated in old persons. Indeed, 

 this obliteration is so common, as to have induced Mayer to regard it as normal. 



f Section of the uterus (transverse). The t\vo bristles are introduced into the orifice* 

 af the Fallopian tubes. 



