orifice, porta, opening - an aperture or hole opening into a bodily cavity; "the orifice into the aorta from the lower left chamber of the heart"

incompetent cervix - (obstetrics) uterine cervix that becomes dilated before term and without labor often resulting in miscarriage or premature birth

uterus, womb - a hollow muscular organ in the pelvic cavity of females; contains the developing fetus