The uterus (womb) is a hollow viscus with thick muscular walls and projects upward from the vagina into the pelvic cavity between the rectum and the bladder. It is pyriform in shape with flattened anterior and posterior surfaces. It is about seven and a half centimeters (three inches) long, five centimeters (two inches) wide at its broadest part, and about two and a half centimeters (one inch) thick. The weight of the virgin uterus is about twenty-eight grams, and that of the postparous organ about forty-eight grams. The uterus is divided into a body, an isthmus, and a cervix, or neck.