Cervix connects with external orifice of uterus
Function
Fertility
The cervical canal is a pathway through which sperm enter the uterus after being induced by estradiol after sexual intercourse, and some forms of artificial insemination. Some sperm remains in cervical crypts, infoldings of the endocervix, which act as a reservoir, releasing sperm over several hours and maximising the chances of fertilisation. A theory states the cervical and uterine contractions during orgasm draw semen into the uterus. Although the "upsuck theory" has been generally accepted for some years, it has been disputed due to lack of evidence, small sample size, and methodological errors.Some methods of fertility awareness, such as the Creighton model and the Billings method involve estimating a woman's periods of fertility and infertility by observing physiological changes in her body. Among these changes are several involving the quality of her cervical mucus: the sensation it causes at the vulva, its elasticity (Spinnbarkeit), its transparency, and the presence of ferning.