The main objective phenomena that take place in the female genitals during the cycle of sexual response are:
1) vaginal lubrication (wetness);
2) vaginal lengthening and enlargement;
3) swelling of the external genitals;
4) swelling of the vaginal lower third, creating the so-called "orgasmic platform";
5) increase of the uterine volume;
6) ascent of the uterus in the pelvis (which happens when the uterus is in anteversion, but does not occur when this organ is in retroversion) (see Note 1, below);
7) during orgasm, the rhythmic contractions of the uterus and the perineal muscles that surround the vaginal entrance; and
8) disappearance of all these changes shortly after orgasm if a new excitatory cycle does not begin.
All these phenomena are due to congestive (caused by expanding of the blood vessels: vasodilation) and myotonic reactions (characterized by an increase in the muscular excitability and contractility), and are controlled by the vegetative innervation of the female pelvic organs. Detailed physiological data on these physical, objective events originated by sexual excitement can be found in Masters and Johnson's pioneer work (Masters, W.; Johnson, V., "Human Sexual Response," Little, Brown and Company, Boston, U.S.A., 1966). It is just after orgasm that the intense pelvic vasocongestion resulting from sexual excitement quickly disappears. If orgasm is not attained, this vasodilation takes much longer to disappear, a fact that, in women, may cause painful phenomena due to the persistent engorgement of the inner genitals.
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