22 



OBSTETRICS. 



is surrounded by a collection of muscular fibres, called the sphincter 

 vaginoR. At its superior and posterior portion, it receives a reflection 

 of peritoneum. (Fig. 8.) 



The uterus is placed at the upper part of the vagina, and hangs 

 in the centre of the pelvis behind the bladder, and before the rectum 

 with its long diameter parallel to the axis of the superior strait, and its 

 superior edge a little above the brim of the pelvis. As the axis of 

 the vagina is nearly parallel with that of the inferior strait, it meets 

 the axis of the uterus at an obtuse angle; any deviation from which, 

 implies a displacement of the womb. It is a hollow pear-shaped 

 body, rounder posteriorly than anteriorly, about 2 5 to 3 inches long, 

 2 inches wide, and very nearly an inch thick. Anatomists divide it 

 into fundus, body and neck. The fundus is that portion above the 

 Fallopian tubes, the cervix is the inferior, cylindrical portion, and the 

 body is that part between the fundus and cervix. (Fig. 9.) 



Fig. 9. 



The uterus has three coats, a serous, a muscular, and a mucous. 

 It is covered anteriorly and posteriorly by peritoneum, which is re- 

 flected laterally to the sides of the pelvis, near the sacro-iliac sym- . 

 physis, forming the broad ligaments, which serve to steady the uterus. 

 The 'middle coat of the uterus is muscular, and classed among" those 

 muscles which are called non-striated, and which are also found in 

 the middle coats of the arteries. There are three sets of fibres, cir- 

 cular, longitudinal, and oblique, which, by their contraction, tend to 

 diminish the cavity and expel the contents of the uterus. The 

 amount of muscular fibres is much increased during pregnancy. 

 The internal coat is generally considered to be a mucous membrane, 

 though there are some obstetrical physiologists who deny it. It 

 extends down into the cervix, whence it is continuous with that of 

 the vagina ; it also lines the Fallopian tubes. Its colour is a pale 

 pink except during menstruation. The uterus is supplied with blood 

 by the spermatic and uterine arteries, and with nerves from the cwrtic 



