The cervix is a thick walled muscular organ which acts to protect the uterus (embryo) from the external environment, may act to select against defective sperm and also as a sperm reservoir after natural mating. The uterine body is about 10 inches in length and connects to the uterine horns at a 90° angle. The uterine horns are also 10 inches long. During early pregnancy, the embryo moves freely between the horns and body.