626 



UTERUS AND ITS APPENDAGES. 



num fi /?g. 431, i, which marks the commence- 

 ment of that canal. The os externum is bor- 

 dered in front and behind by two smooth lips, 

 whose commissure on either side forms the 

 lateral boundaries of the orifice. The lips 

 constitute the terminations of the anterior 

 and posterior cervical walls respectively. 

 They are accordingly distinguished as the 

 anterior and posterior lips of the os uteri. 

 Their position and form are most conveniently 

 shown in a vertical section of the part {fig. 

 426. and 433.). The anterior lip is the 

 smaller; it projects but slightly into the 

 vagina, but it lies at a lower level than the 

 posterior one, on account both of the greater 

 length of the anterior wall of the uterus, and 

 also from the inclination of the upper part of 

 the organ forwards. In an antero-posterior 

 view, the anterior serves to conceal the pos- 

 terior lip, which lies higher in the pelvis, both 

 from the comparative shortness of the pos- 

 terior uterine wall, and also from the tilting 

 forward of the entire organ ; nevertheless the 

 posterior lip makes a greater projection into 

 the vagina, because the walls of that canal 

 are reflected off at a higher point upon the 

 cervix posteriorly than anteriorly. This un- 

 equal form of the two lips doubtless gave 

 origin to the term os tincae, by which the 

 older anatomists designated the part. 



In no portion of the uterus is the difference 

 between the nulliparous and multiparous or- 

 gan so marked as in the vaginal portion of the 

 cervix. After the birth of many children, this 

 part becomes much enlarged, soft, flaccid, and 

 of irregular form, with notched margins ; but 

 in the virgin it has uniformly the smooth, 

 even, conical figure just described, while its 

 consistence is nearly that of soft cartilage. 



External surface. The uterus, being a hol- 

 low or cavitary organ, possesses both an ex- 

 ternal and an internal surface. The external 

 surface exhibits two faces, anterior and poste- 

 rior ; three borders, one superior and two 

 lateral ; and three angles, two superior and 

 one inferior. 



The anterior face is smooth, and gently 

 convex in the transverse direction (figs. 427 

 430.), but often slightly curved from above 

 downwards (fig. 426.). It is covered by peri- 

 toneum in all but its lower part, where this 

 membrane is reflected off to give a covering to 

 the bladder at a distance of not less than one 

 fourth of the entire length of the uterus from 

 its lower extremity. The posterior face is more 

 decidedly convex ; and in some subjects, espe- 

 cially in multiparae, it exhibits a marked pro- 

 minence along the median line, from which the 

 walls proceed outwardly in two nearly level 

 planes. These, meeting the less convex an- 

 terior walls at the lateral border, give to a 

 transverse section of such an organ an outline 

 more or less triangular (fig. 428.). The pos- 

 terior face also receives an investment of peri- 

 toneum. The membrane here, after covering 

 the entire posterior surface of the uterus, 

 usually dips down to cap the upper extremity 

 of the vagina. (Fig. 426. c r.) 



The superior uterine border is moderately 



convex ; it extends from the point of entrance 

 of one Fallopian tube to that of the other 

 (fig. 43 1.//). This border is entirely co- 

 vered by peritoneum. The two lateral bor- 

 ders extend from the point of entrance of 

 either Fallopian tube downwards to the 

 lower extremity of the uterine neck, as far 

 as the margins of the os uteri. These 

 borders are flexuous, being convex above, 

 concave towards and below the centre of 

 the organ, again slightly convex about the 

 middle of the cervix, and finally terminating 

 at the os uteri, after having their continuity 

 interrupted by the circular attachment of the 

 vagina near the termination of the uterine 

 neck. The lateral borders are uninvested by 

 peritoneum; for it is here that the two laminaa 

 of that membrane, which form the broad liga- 

 ment, meet to inclose the uterus; and by these 

 two lateral borders, the blood-vessels and 

 nerves supplying the organ enter it without 

 penetrating its outer or serous coat (fig. 428.). 



The two superior angles are formed at the 

 points of entrance of the Fallopian tubes. 

 The inferior angle is occupied by the vaginal 

 portion of the cervix and the os uteri. 



Internal surface and cavities of the bodij and 

 cervix. It has been stated that the walls of 

 the uterine body are in nearly close apposi- 

 tion internally, leaving only a small interme- 

 diate space, termed the cavity of the uterus, 

 which is easily displayed by cutting through 



Fig. 426. 



Vertical section of the uterus parallel with its lateral 

 borders. 



a, anterior, and p, posterior, lip of cervix ; t, in- 

 ternal os uteri ; v a, vagina ; f, fornix ; c, loose con- 

 nective tissue immediately above the fornix; r, 

 point of posterior reflection of the peritoneum on to 

 the rectum, forming the retro-uterine pouch or space 

 of Douglas; bb, line of attachment of the cervix to 

 the bladder. The peritoneum ceases at the upper 

 b, in front. (Ad Nat.) 



