886 A MANUAL OF ANATOMY 



from before backwards. The lateral borders of the uterus are 

 sloped downwards and inwards, and at the junction of the upper 

 two-thirds and lower third of the organ there is a slight constriction 

 or concavity, called the isthmus, which is also present in front 

 and behind, and is most conspicuous in early life. The part between 

 the fundus and the isthmus is the body, and the part below the 

 isthmus is the cervix. 



The body, which is 2 inches long, is triangular, and presents 

 two smooth surfaces, anterior and posterior, and two lateral borders. 

 The anterior or vesical surface, which has an inclination downwards, 

 is slightly convex. The posterior or rectal surface, which has an 

 inclination upwards, is more markedly convex. Each lateral border 

 extends from the superior angle to the isthmus, and is sloped 

 downwards and inwards. The superior angles are situated at the 

 points of entrance of the Fallopian tubes, and correspond with the 

 portions of the uterus which are elongated into cornua in some animals. 



The cervix, which measures i inch in length, is cylindrical, 

 and narrower than the body. It is received into the upper part 

 of the anterior wall of the vagina, the walls of which are at- 

 tached to it in such a manner as to divide it into two portions — 

 supravaginal and vaginal. The posterior wall of the vagina ex- 

 tends higher upon the cervix behind than the anterior wall does 

 in front. The anterior surface of the supravaginal portion, which 

 is about ^ inch in extent, is related to the base of the bladder, with 

 the intervention of some loose cellular tissue. The posterior 

 surface of the supravaginal portion, which is about ^ inch in extent, 

 forms a part of the anterior wall of the pouch of Douglas, and is 

 crossed transversely by the torus uterinus. At the lower end of 

 the vaginal portion, where the cervix is slightly protuberant, there 

 is an opening, called the OS uteri externum, through which the 

 cavity of the cervix communicates with that of the vagina. This 

 opening is also known as the os tincce, because it is supposed to 

 resemble the mouth of the tench fish, on account of its lips being 

 of unequal size. In early life this opening is circular, but later, in 

 the virgin, it assumes the form of a transverse slit about -^ inch long, 

 it is bounded by two lips, anterior and posterior, which in the 

 virgin are smooth, but in inultiparae they are often more or less 

 fissured, especially the posterior Up. The anterior lip is thick, 

 round, and short, whilst the posterior is thin, sharp, and long. 

 The anterior hp descends lower into the vagina than the pos- 

 terior, by reason of the oblique manner in which the cervix uteri 

 passes into the canal. It is the anterior lip which first meets the 

 finger in making vaginal examinations. The greater length of the 

 posterior lip is due to the fact that the posterior wall of the vagina 

 extends higher on the back of the cervix than the anterior wall 

 does in front. The os uteri externum is directed downwards and 

 backwards towards the posterior wall of the vagina, this being due 

 to the oblique position of the cervix. 



