MENSTRUATION.
Menstruation (menstrual flow, menses, catamenia, flow, catamenial flow, etc.), is a function of the female organism, a temporary and inter mitting function, that is made manifest by two kinds of phenomena: in ternal phenomena, the evolution of the vesicle of de Graaf, and the formation of the corpora lutea; external phenomena, of which the most apparent is a bloody flow through the genital passages. Temporary, for it exists only from puberty to the menopause, this function is intermittent, and we may say periodic, for it is manifested by a series of phenomena which are reproduced nearly every month. This bloody discharge is only the consequence of the hypermmia which is produced in the whole genital system of women: ovary, tubes, uterus and broad ligaments.
According to Richet, the venous system of the broad ligament plays a considerable part in this function, and the plexus which the veins form in these ligaments, may be tumefied enough to become appreciable to vaginal touch, during the menstrual period. We have already seen that according to Richet, these veins become varicose, may even burst in cer tain cases and become the origin of hematoceles, which are above all ob served at the time of the catamenia.
Anatomical Modifications of the Genital System produced by Menstruation.
The anatomical phenomena which occur during menstruation are not limited to the ovary. The whole genital apparatus participates in the vital activity then produced, and there occurs, in the vascular portions especially, a series of modifications which have been carefully studied by Coste, Ch. Robin, Richet, Rouget and Kobelt. Rouget has shown that the ovary, the tube, the uterus and their vessels, are surrounded by a system of muscular fibres which, under the influence of the ovarian nisus, contract, and, compressing the venous plexus, retard the flow of blood. The flow of blood being retarded, the circulation is, in turn impeded; hence, increase of tension in the capillaries and other vessels; hence, arrest of blood in the uterine tissue, exaggerated congestion, and, as the final phenomenon, the rupture of the capillaries; and appearance of the menstrual flow.
The uterus is, next to the ovary, most influenced by the menstrual function. Under the influence of congestion its volume increases a quar ter, a third, and sometimes more. It thus becomes easily accessible through the abdominal wall. According to Rouget, the uterine tissue, filled with blood, suffers a true erection. The vertical diameter of the uterine cavity increases from .19 to .39 of an inch according to Richet. Its fibres become more red, more supple, and more spongy.
The cervix becomes larger, softer, and violet colored. The external os opens slightly; the cervix seems to lengthen and to become more ac cessible to the finger of the investigator. The internal os opens to give passage to the fluids from the cavity of the body of the uterus.
The mucous membrane of the uterine cavity becomes thicker, and is colored a deep reddish-brown. It becomes folded and mamillated. The hypertrophied glands become the seat of an abundant secretion, the sub epithelial vascular net-work of Robin becomes more apparent, surrounds the enlarged orifices of the glands, and thus gives the mucous membrane the appearance of a sieve. (See Figs. 65 and 66). the epithelium which covers it loosens, the capillaries, ceasing to be supported, yield to the pressure of the blood, and burst in a number of small crevices, just as the pituitary mucous membrane bursts in epistaxis, and the blood flows through these innumerable microscopic openings.
The menstrual fluid is then composed of blood, the products of mucous secretion and epithelial cells.
It is the mucous membrane of the body, and especially of the fundus, that furnishes the catamenial discharge. The mucous membrane of the cervix scarcely participates. Its vessels are more resisting and do not burst; they merely dilate. Thus, the discharge that proceeds from the cervix is purely mucous, and only mixes with that which comes from the cavity of the body.