The uterus is covered, front and back, by a fold of the peritoneum, except the lower part of the anterior wall where the peritoneum is reflected up over the bladder. It is lined with a thick, velvety, highly vascular mucous membrane, the endometrium, the surface of which is covered by ciliated, columnar epithelium. Embedded in the endometrium are numerous mucous glands which dip down into the underlying, muscular wall.
The uterus as a whole is comprised of three parts: the fundus, that firm, rounded, head-like part above; the body, or middle portion, and the cervix, or neck, below. It is in the body and cervix that we find the long, narrow uterine cavity, divided by a constriction into two parts. The cavity of the body is little more than a vertical slit, being so flattened from before backward that the anterior and posterior surfaces are nearly if not quite in apposition. It is somewhat triangular in shape with an opening at each angle. (Fig. [11].) The lower of these openings leads into the cavity of the cervix through a constriction termed the internal os, while at the cornua, or two upper angles, are the openings into the Fallopian tubes.
The cavity of the cervix is spindle-shaped, being expanded between its two constricted openings, the internal os above and the external os below, which opens into the vagina. The external os in the virgin is a small round hole but has a ragged outline in women who have borne children.
This oblong, muscular body, the uterus, is suspended obliquely in the centre of the pelvic cavity by means of ligaments. In its normal position the entire organ is slightly curved forward, or ante-flexed, the fundus being directed upward and forward and the cervix pointing down and back. This position is affected by a distended bladder or rectum, and also by postural changes in the body as a whole. The cervix protrudes into the anterior wall of the vagina for about one-half inch and almost at right angles, since the vagina slopes down and forward to the outlet.
The upper part of the uterus is held in position by means of ligaments, the lower part being embedded in fat and connective tissue between the bladder and rectum. This more or less of a floating position makes possible the enormous increase in size and upward push or extension of the uterus during pregnancy. The pregnant uterus becomes soft and elastic as it grows. At term it is about a foot long, eight to ten inches wide, and reaches up into the epigastric region. This growth is due in part to the development of new muscle fibres and in part to a growth of the fibres already existing in the uterine wall.
After labor the uterus returns almost, but never entirely, to its former size, shape and general condition.
The Fallopian tubes are two tortuous, muscular tubes, four or five inches long, extending laterally in an upward curve, from the cornua of the uterus and within the folds of the upper margin of the broad ligament, by which they are covered. At their juncture with the uterus, the diameter of these tubes is so small as to admit of the introduction of only a fine bristle, but they gradually increase in size toward their termination in wide trumpet-shaped orifices, which open directly into the peritoneal cavity. Finger-like projections called fimbriæ, fringe the margins of these openings.
The mucous lining of the tubes is covered with ciliated epithelium and is continuous with that of the uterus. At the fimbriated extremities of the tubes this lining merges into the peritoneum, the serous lining of the abdominal cavity.
Just here it will be well to say a word about the peritoneum because of the possibility of its becoming infected during labor and the lying-in period, and the very grave consequences of such infection. It is a delicate, highly vascular, serous membrane which both lines the abdominal cavity and covers the abdominal and pelvic organs, which press into its outer surface and are covered much as one’s fingers would be covered by pushing them into the outer surface of a child’s toy balloon. The continuity of this membrane is broken only where it is entered by the Fallopian tubes.
The ovary, the sex gland of the female, is a small, tough ductless gland, about an inch long and three-quarters of an inch wide, or about the size and shape of an almond. It is greyish pink in color and presents a more or less irregular, dimpled surface. An ovary is suspended on either side of the uterus, in the posterior fold of the broad ligament, by which it is partly covered. Its outer end is usually attached to the longest of the fimbriated extremities of the Fallopian tube, the fimbria ovarica, which has the form of a shallow gutter, or groove. The inner end of the ovary is attached to the ovarian ligament, which in turn is attached to the uterus below and behind the tubal entrance.