In virgins this foramen is hidden by a membrane, called the hymen.
The study of this membrane, considered by Sappey and K011iker as a fold of the vaginal mucosa, and by Tarnier and Courty as the result of the union of the vaginal and vulvar mucous membranes, was finally taken up by Budin. According to him the vagina represents a glove finger which is terminated at its anterior extremity by a circular orifice. It is this perforated extremity of the glove finger which is insinuated between the labia minors, forming what is called the hymen. The hymen, as a true, special, distinct, and independent membrane does not exist. The vaginal orifice is nothing but the hymeneal foramen. This anatomical arrangement explains certain difficulties in the first sexual intercourse, the retardation which the head meets with in its expulsion in certain primiparze, and, finally, the change in aspect of the vaginal orifice and the formation of myrtiform caruncles, after the first confinement.
Structure of the Vagina.—The walls of th3 vagina consist of: an ex ternal cellular-fibrous coat, a middle muscular layer, an internal or mucous coat, and vessels and nerves.
1st. External Coal.—This is cellulo-fibrous, and unites the vagina to the surrounding parts. It is composed of fibres of connective tissue mingled with elastic fibres.
2d. Muscular Layer.—This forms two-thirds of the thickness of the vagina. It is composed of superficial longitudinal fibres, which are in serted in front on the ischio-pubic rami, while behind, these fibres are continuous with the external layer of the muscular coat of the neck of the uterus. Below this is a layer of fibres which cross each other, and form a plexiform net-work.
3d. The mucous coat is ashy grey or reddish in color, and about .029 inches thick. It is closely united to the muscular layer, its superficial surface is covered with stratified pavement epithelium, which entirely covers the papillae which depend from it. Luschka considers it very rich in muciparous glands. Sappey has never found them.
The arteries come from the hypogastric, by the vaginal branch of the uterine arteries, the inferior vesicals and internal pudic. Their final ramifications penetrate to the papillae.
The veins empty into the venous plexus which passes along the sides of the vagina.
The lymphatics go to the lateral glands of the cavity, and to the in guinal.glands.
The nerves are very numerous and come from the hypogastric plexus.
Bulbs of the Vagina.—Kobelt compares them to leeches filled with blood, the buccal extremity of which corresponds to the clitoris, while the body would be attached to the anterior orifice of the vagina.
They are two erectile organs which are, in reality,-situated on the an terior and lateral portions of the vagina, below and witliin the pubic rami. In the state of erection they are 1.3 inches long, .58 inches wide, and from .39 to .46 inches thick.
Their internal concave surface embraces the circumference of the vaginal orifice, their external convex surface is covered by the constrictor vaginie.
Their anterior border is the point of departure of numerous veins, which communicate with those of the labia minors, and then empty into the intermediate plexus at the bulb and corpora cavernosa. No vein leaves the posterior border. The inferior extremity projects slightly on the transverse diameter of the vaginal orifice. The superior extremity is thin, and slender, and is adjacent to the urethral canal, and the clitoris. It is united to that of the opposite side by veins and smooth muscular fibres. Thus certain authors consider the bulb as a single median organ.
Their structure is identical with that of the corpora cavernosa, and the spongy portion of the urethra in the male.
The vagina is above all an organ of copulation, and serves a3 the re ceptacle of the semen, and gives passage to the menstrual flow and the fret us.
According to Beige], Eichstadt, IIolst, Braune, Pirogoff, Kohlrausch and Lusclika, the posterior lip of the cervix being normally directed backward, forms, by its contact with the posterior wall of the vagina, a sort of infundibulum, or small fosse, which is called receptaculum seminis.
The semen is deposited there after ejection. The neck of the uterus, in consequence of the straightening of the organ, at the moment of the con gestion determined by coition, thus becomes bathed directly in the fertil izing fluid.