Uterus

3. Uterus : It is commonly called the womb, a a hollow, muscular, pear-shaped organ located above and behind the urinary bladder, about 7.5 cm long, 5 cm broad and 2.5 cm thick. It is divided into three regions:

a. Fundus : the upper dome-shaped part, where implantation of the embryo normally occurs.

b. Body : the broad part of the uterus that gradually tapers downward.

c. Cervix : the narrow neck, about 2.5 cm long, that extends into the vagina; its passage has two openings, an internal os towards the body and an external os towards the vagina.

Internally, the uterine wall is made up of three layers. The outermost layer is the perimetrium; the middle, thick, muscular layer is the myometrium, made of thick smooth muscle whose vigorous contractions cause labour during parturition (childbirth); and the innermost layer, the endometrium, a mucosal membrane made of stratified epithelium, whose thickness changes regularly across the menstrual cycle. The endometrium is richly supplied with blood vessels and uterine glands that provide nourishment to the developing foetus.