The uterus lies in the pelvis and has three layers. The endometrium is a specialised layer able to receive a blastocyst and with it form a placenta to support a growing foetus. The myometrium is a thick smooth muscle layer able to stretch to match the growth of the developing foetus and then expel it at birth. The perimetrium is a thin covering to the uterus that is largely peritoneum. The cervix is the entrance to the body of the uterus and the uterine tubes connect to the ovaries. Ligaments, endopelvic fascia and the levator ani muscle group all support the uterus.