Uterus

The uterus (plural uteri) or womb is a major female hormone-responsive secondary sex organ of the reproductive system in humans and most other mammals. Things occurring in the uterus are described with the term “in utero”. The lower end of the uterus, the cervix, opens into the vagina, while the upper end, the fundus, is connected to the fallopian tubes. It is within the uterus that the fetus develops during gestation.
The uterus is located within the pelvic region immediately behind and almost overlying the bladder, and in front of the sigmoid colon. It is pear-shaped and about 7.6 cm (3.0 in) long, 4.5 cm (1.8 in) broad (side to side), and 3.0 cm (1.2 in) thick. A typical adult uterus weighs about 60 grams. The uterus can be divided anatomically into four regions: the fundus – the uppermost rounded portion of the uterus, the corpus (body), the cervix, and the cervical canal. The cervix protrudes into the vagina.
The uterus is held in position within the pelvis by ligaments, which are part of the endopelvic fascia. These ligaments include the pubocervical ligaments, the cardinal ligaments, and the uterosacral ligaments. It is covered by a sheet-like fold of peritoneum, the broad ligament.
The uterus has three layers, which together form the uterine wall. From innermost to outermost, these layers are the endometrium, myometrium, and perimetrium.

Source : wikipedia
https://en.wikipedia.org/wiki/Uterus