myometrium

The myometrium is the muscular middle layer of the uterus, comprising the bulk of the organ's wall. It is composed of densely packed smooth muscle fibers arranged in three layers with different fiber orientations. This muscular layer is crucial for the uterus's ability to contract, particularly during childbirth. The uterus itself is an inverted pear-shaped, hollow, muscular organ with a glandular lining called the endometrium. It is situated in the pelvis and connects to the fallopian tubes at the top and the cervix, which projects into the vagina, at the bottom. The myometrium's contractions are essential for expelling the fetus during labor.1