Womb, or UTERUS, a flattened, pear-shaped organ, lying in the line of the axis of the outlet of the Pelvis (q.v.), with its base directed upwards and forwards, and its narrower neck or cervix directed downwards and slightly backwards. In the unimpregnated condition it is about 3 inches in length, 2 in breadth, and 1 in thickness, and weighs about an ounce and a half. On laying it open its cavity is found to be very narrow, and to contain only a little mucus. Its walls are nearly half an inch thick, and are mainly composed of muscle-cells and fibres running irregularly in all directions except round the os, where they make a partial sphincter. This muscular layer, 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 membrane 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 membrane abounds in small mucous follicles, and is provided with ciliated Epithelium (q.v.). The lower end of the cervix projects slightly into the vagina, communicating with it through the os uteri externum, which is nearly round in the virgin, and transverse after parturition. This orifice leads into a narrow canal which terminates at the upper end of the cervix in a smaller opening, the os 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 (see under OVARIES), 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 1½ to 3 lb. The term appendages to the uterus is given to the Fallopian Tubes and Ovaries (q.v.), which are enclosed 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 it is able to increase vastly in bulk with comparatively little 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 in the Ruminantia, Pachydermata, Solipedia, and Cetacea; and it is said to be divided where, as in most of the Carnivora and Edentata, and some Rodentia, it has only a very short body, which speedily divides both externally and internally, and is continuous with the oviducts or Fallopian tubes. The uterus is actually 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 intestiform uterus, which has two completely distinct openings lying near to each other within the vagina. In the Marsupialia and Monotremata the modifications of this organ are still more singular.
The chief offices or functions of the womb may be divided into those which relate to (1) Menstruation, (2) Insemination, (3) Gestation, and (4) Parturition.—For further details, see the standard works on anatomy and physiology.
DISEASES OF THE WOMB.—In consequence of its mobility, but particularly of the periodical changes it undergoes during the processes of menstruation and childbearing, the womb is an organ extremely liable to disease. It is of course quite impossible in such a work as the present to do more than indicate generally some of the more important of the morbid conditions met with and their symptoms; the more, as even a trained observer can seldom decide from the progress and symptoms of a case without a thorough examination what the nature of the disease really is.
Malformations occur as a result of imperfect development; the womb may be small or rudimentary, or it may be double throughout or in its upper part, as is normally the case in some of the lower animals.
Displacements forwards or backwards are common in consequence of the mobility of the organ. Their exact causation is not always perfectly understood; but they often lead to much pain and discomfort, to inflammation of the organ, to disturbance of menstruation, and to sterility. In many cases they may be remedied by mechanical means.
Prolapse, or displacement downwards of the womb, generally occurs in consequence of injury during childbirth. The cervix, or even the whole womb, may project from the orifice of the vagina, causing great distress and discomfort. Mechanical support, with or without previous operation, will usually give relief.
Inflammation, affecting the cervix only or the whole womb, often follows childbirth, or may result from displacement of the womb, cold, and other causes. But the most fruitful sources of it are probably neglected miscarriages; for it is not sufficiently recognised that almost as much care is required to ensure complete restoration to health after a miscarriage as after a confinement. Various forms and degrees of inflammation vary much in their results, but generally speaking they lead to abnormal discharge from the vagina (popularly called 'whites'), irregular menstruation, pain in the back and pelvis, and often to great constitutional weakness and nervous disturbance. The most suitable treatment varies much in different cases, but is often tedious and troublesome.
The womb is a very frequent seat of tumours. In many cases the chief symptom is excessive menstruation; but in some forms of fibroid tumour there may be such an absence of symptoms that the growth is discovered only by accident. Pedunculated tumours, or Polypi (q.v.), within the uterus can generally be removed with little trouble or risk. 'Fibroid' tumours, consisting of fibrous tissue with a variable proportion of unstriped muscular fibre, resembling that normally present in the uterus, are by far the most frequent tumours in this situation. They are most common in middle life; after the 'change of life' they usually cease to grow, or to give rise to any symptoms except those due to their mere mechanical presence. They may be of enormous size; tumours of 70 or 80 lb. have been met with. Considering their frequency, it is surprising how seldom they lead to the death of the patient; but they often cause excessive hæmorrhage and great debility. When situated near the internal surface of the womb, they are sometimes expelled spontaneously. Removal by ordinary surgical methods has often been practised in severe cases, and with steadily improving results. In 1884 Dr Apostoli of Paris brought into notice a method he has introduced of passing strong electric currents through the womb, for which he claims that it produces diminution of hæmorrhage and practical cure in many cases without the risks of an operation. Medical opinion is still much divided as to the results and value of this procedure.
Malignant tumours of the womb are also very common; of all the organs of the body indeed this is by far the most frequent seat of cancer. In the vast majority of cases the disease begins in the cervix; and at an early stage it may sometimes be removed with success. But if not completely eradicated it speedily spreads to neighbouring parts, and a fatal result is inevitable. It is rare before thirty years of age; most common between forty and sixty. The first symptom is usually hæmorrhage; pain is rarely present in the earlier stages, and may be absent throughout. Sarcoma is sometimes met with, but is much less common than cancer in this situation.
See also GESTATION, MENSTRUATION, OBSTETRICS, OVARIOTOMY, REPRODUCTION, and works cited at STERILITY.