The uterus is generated menstruation and fetus organs located in the pelvis center, between the bladder and rectum. Uterine size and age and birth-related, not producers Approximately 7.5cm, width 5cm, thickness 3cm, the uterus can be divided into bottom, body and neck in three parts. Uterine cavity was inverted triangle, a depth of approximately 6cm, the top corners as "uterine horn", leading to the fallopian tubes. Bottom narrow as "isthmus", about 1cm. Isthmus gradually expanded during pregnancy, labor, formed when the lower uterine segment. Palace and cervical ratio depending on age, 1:2 infancy, and adolescence is 1:1, 2:1 growth period. Normal uterus slightly bent forward, prone on the bladder wall, almost at a right angle with the vagina, rectum, bladder filling positions may vary change depending on the degree.