The uterus does not get bigger before menstruation and is the same size as normal. The uterus is shaped like an inverted pear and is about 7.5 cm long, 5.0 cm wide and 2.5 cm thick in adult women. The cervix is about 2.5-3.0 cm long and its lower half protrudes into the vagina, which is the vaginal part of the uterine cervix. The inner cavity of the uterine body is the uterine body cavity, which is an inverted triangle with a flat front and back. The inner cavity of the uterine cervix is called the cervical canal and has two mouths, the inner and outer. The inner opening communicates with the uterine body cavity and the outer opening leads into the vagina. The external opening of the cervical canal is often round in the unborn woman and becomes a transverse cleft after delivery.