The length of the Womb, after puberty, is about three inches; its breadth at the upper part, or fundus, about two inches; and at the cervix, or neck, about one inch. The cavity in the interior is small, owing to the thickness of the walls, and its form is triangular. The shape of the Womb resembles a pear, somewhat flattened, from before backward. Previous to puberty its size is much smaller, and with those who have had children it often exceeds the dimensions we have given.
The Neck, or narrow part, (c. Plate IV.) is much changed by pregnancy. In virgins it is long and pointed, and somewhat enlarged in the middle. In those who have borne children it is considerably shorter, more obtuse, and less regular in its form. The cavity in the Neck is larger in the middle than at either end, as will be seen in Plate IV.
The Os Tincæ, or mouth of the Womb, also undergoes considerable change from the same cause. In the young person it is merely like a small slit, scarcely to be felt, but after pregnancy it much enlarges, and remains more or less permanently open. The anterior lip, or the one in front, is somewhat larger than the posterior one.
The body of the Uterus is formed of a very dense, gray colored, muscular substance, possessing astonishing contractile power. The interior is lined, like the Vagina, with a mucus membrane, and the whole organ is plentifully supplied with arteries, veins, and nerves.
One of the most remarkable properties of the Womb is that of being able to distend to an extraordinary degree, and then retract again to nearly its original size. The force which it sometimes exhibits during its contraction is very great, being sufficient to separate, and even break, the bones of the mother's pelvis, and paralyze the hand of the operator when introduced. The Muscular Fibres on which this contractile force depends are most obvious during gestation; they then appear very numerous, and very curiously disposed, some of them ramifying in almost every direction, as will be seen by Plates V, VI. It is owing to this that the Womb contracts in every conceivable direction, and thus presses, during labor, on every part of the child's body.
PLATE V.
Figures 1 and 2.
Fig. 1. In this plate represents the Muscular Fibres a little exaggerated, so that they can be more distinctly seen.—a. a. are the orifices of the Fallopian Tubes.
Fig. 2. Represents the natural appearance, the fibres not being quite so distinct, though sufficiently obvious.—a. a. The orifices of the Fallopian Tubes.