WOMB, THE, professionally known as the uterus, is a flattened, pear-shaped organ, whose position and various parts will be best understood by a reference to fig. 1. It consists of a body (1), a base or fundus (2), a neck, or cervix (3), and a mouth or os uteri (4). It lies in the line of the axis of the outlet of the pelvis (q v.), with base directed upward and forward, and the neck directed slightly backward. In the unimpreg nated condition, which we are now considering, it is about three inches in length, two in breadth, and one in thickness, and weighs about an ounce and a 'half. On lay ing it open, or exploring its interior by the introduction of an instrument through the os uteri, its cavity is found to be very narrow, and to contain a little mucus. Its walls are nearly half an inch thick, and are mainly composed of muscle-cells and fibers running irregularly in all directions except round the os, where they make a partial sphincter. This muscular coat, which constitutes the bulk of the organ, is covered externally with a serous coat, derived from the peritoneum, and is lined internally by a mucous coat continuous with that of the canal called the vagina, by which the interior of the womb communicates with the outer surface of the body. This mucous coat abounds in small mucous follicles, and is provided with ciliated epithelium (q.v.). The neck or cervix of the womb is distinguished from the body by a well-marked constriction. The mouth, or os, projects slightly into the vagina (which is shown as laid open anteriorly in the fig. ure). This opening is nearly round in the virgin, and transverse after parturition. It is of considerable size, and is named the OrifiCiUM uteri externunz; it leads into a narrow canal which terminates at the upper end of the cervix in a smaller opening, the orificium.
internum, beyond which is the shallow triangular cavity of the womb, of which it forms the lower angle, while the two upper angles, which are funnel shaped, constitute the beginning of the Fallopian tubes (q.v.), whose apertures are so small as only to admit the passage of a fine bristle. The blood-vessels and nerves enlarge in a very remarkable way during pregnancy, so as to adapt themselves to the increased wants of the organ, which, at the ninth month of utero-gestation, weighs from two to four pounds. organ,
term appendages to the uterus is given to the Fallopian tubes and ovaries (q.v.) which are inclosed by the lateral folds of the peritoneum called the broad ligaments. The womb is suspended in the pelvic cavity in such a way as, by its mobility, to escape rude shocks from without or disturbance from the varying conditions of the surrounding viscera, while at the same time to allow of its vastly increasing in bulk with comparatively lit tle discomfort when pregnancy occurs. This is 'effected by several duplicatures of peritoneum, containing variable quantities of fibrous and muscular tissue, and known from their form or connection as the broad, the round, the utero-sacral, and the utero vesical ligaments.
The uterus is an organ peculiar to the mammalia, and in comparatively few of them (excepting the apes and cheiroptera) is it of the simple oval or triangular form which we have described. It is two-horned iu the ruminantia, pachydermata, solipedia, and ceta cea; and it is said to be divided where it has only a very short body, as in most of the carnivora and edentata, and some rodentia, which speedily divides both externally and internally, and is continuous with the oviducts or Fallopian tubes. The uterus is actu ally double in some of the edentata, and in most of the rodentia, including the mouse and hare; in which each Fallopian tube passes into an iutestiniform uterus, which has two completely distinct openings lying near to each other within the vagina. In the marsu plata and monotremata, the modifications of this organ are still more singular.
It is impossible to do more than name the chief offices or functions of the womb. They may be divided into those which relate to (1) menstruation (q.v.), (2) insemination, (3) gestation, and (4) parturition.—For a complete account of the anatomy, physiology, and pathology of the uterus and its appendages, we must refer to a masterly article by Dr. Arthur Farre on that subject in the last volume of the Oyelopo.dia of Anatomy and .Physiology.