The Uterus.—­ The internal organs of generation are the uterus, the ovaries, and the Fallopian tubes.  Of these, the ovaries and the uterus are the essential female organs of generation.  The virgin uterus is a small, hollow, muscular organ, somewhat pear-shaped, whose cavity is about one and a half inches deep.  The uterus is divided by a natural constriction into a body and a neck.  The neck, or cervix, is somewhat spindle-shaped, and has a canal running through its center which opens by a small aperture—­ the so-called external orifice,—­ into the vagina.  In the virgin uterus the apposition of the anterior and posterior walls reduces the cavity to little more than a longitudinal cleft.  With the advent of old age the whole organ suffers marked atrophy.

The uterus is situated in the middle of the pelvic cavity, between the bladder and the lower bowel.  It is held in place by broad elastic bands which go to different sides of the pelvis; it is also in part supported by the structures below and above it.  But so loosely is the uterus held that it is easily pushed about—­ as, for instance, by a full bladder or a packed bowel.  And persistently allowing the bladder to become overfull, and failure to have a daily evacuation of the bowels, are prolific sources of displacements of the womb.

Respiratory Movements of the Uterus.—­ When no constrictions are placed about the waist, the uterus moves freely up and down with every respiration.  So distinctly and with such regularity do these movements take place that an operator by watching the movements of the uterus can tell the effect that the anesthetic is having on the patient’s breathing.  These so-called respiratory movements play a very important role in the circulation of the uterus, and in the return of the venous blood to the heart.

Anything which interferes with these movements, as the use of corsets, or of tight bands around the waist, prevents the free return of the venous blood.  The uterus becomes congested, and through the constant abnormal weight of the organ itself, as well as the pressing down upon it from above of the superincumbent organs, the uterus is pushed down below its normal position, the ligaments whose duty it is to hold it up become relaxed, and the unhappy woman suffers all the agonies that are attendant on the “falling of the womb.”  For this reason the disorder is frequently met with in women who have never borne children as well as in those who have.

The Fallopian Tubes.—­ The Fallopian tubes extend from the upper, rounded angles of the uterus, within and along the free margin of the broad ligaments, for a distance of about two inches, to the vicinity of the ovaries, where each one terminates in a funnel-shaped orifice surrounded by a series of fringed processes.  The lumen of the tube is narrowest at its inner end, where it opens into the cavity of the uterus by a minute orifice which scarcely admits a bristle; the diameter of the canal gradually increases until it reaches its ovarian extremity.  The mucous lining of the tube is clothed by a single layer of hair-like epithelium, whose current sweeps from the ovarian toward the uterine end of the tube; and it is these movements which propel the ovum from the ovary to the uterus.