PELVIS 637 



behind it is convex, the convexity of the posterior surface, 

 however, being much more marked, especially in its upper 

 part, than that of the anterior surface. Each lateral border 

 is connected to the corresponding broad ligament, and im- 

 mediately below the entrance of the uterine tube it is joined, 

 in front, by the round ligament, and behind, by the ligament of 

 the ovary. Inferiorly, the body of the uterus is marked off from 

 the cervix by a slight constriction, which, although very 

 apparent in the infant, becomes less distinct as puberty 

 approaches, and usually disappears altogether after parturition. 

 This constriction is called the isthmus. 



Cervix Uteri (Neck or Cervix). The cervix is about an 

 inch in length (25 mm.); it is narrower than the body and 

 more cylindrical in form. It projects into the upper end 

 of the vagina, the walls of which are attached around it. 



To obtain a satisfactory view of the relation of the uterus 

 to the vagina, both organs should now be split sagittally, 

 care being taken to avoid injuring the rectum. When this 

 has been done the posterior wall of the vagina will be found 

 to ascend to a higher level on the cervix than the shorter 

 anterior wall (Figs. 244, 247). On the lower extremity of 

 the cervix, which rests against the posterior vaginal wall, 

 there is an orifice, the orificium extermtm uteri (O.T. os uteri 

 externuni). This opening, in nulliparse, is always a small 

 transverse slit with rounded anterior and posterior lips, but in 

 women who have borne children it is usually larger, and 

 its margins are more irregular in outline. The anterior lip 

 is the shorter, and it is placed at a lower level in the vagina. 

 This difference in the level and in the length of the two lips is 

 due to the fact that the uterus passes obliquely through the 

 vaginal wall. The part of the cervix which projects into the 

 vagina is the portio vaginalis \ the part above is termed the 

 portio supravaginalis. 



Cavum Uteri. The cavity of the uterus is separable into 

 two parts, the cavity of the body and the cavity of the cervix. 

 The cavity of the body is a mere cleft, triangular in outline, 

 which lies between the anterior and posterior walls. The 

 base of the triangle is above, and at each of its lateral angles 

 a uterine tube opens into the cavity. The apex is below, 

 where the cavity of the body joins the cavity of the cervix at 

 a constricted aperture of communication called the orificium 

 internum uteri (O.T. os uteri internum). 



