To better understand endometriosis, it helps to understand the anatomy of the uterus.

The uterus, or womb, is part of the female reproductive system. The cervix is the lowest part of the uterus. The ovaries, fallopian tubes and vagina are the other parts of the female reproductive system.

The inner lining of the uterus is called the endometrium. Before ovulation, the endometrium grows and becomes thick. If fertilization does not occur than the endometrium is shed during a menstrual period. If an egg is fertilized, the endometrial tissue and blood vessels support the fertilized egg after it has implanted in the uterus.

Anatomy examples:

• The uterus, cervix, and vaginal canal
• The bladder
• The fallopian tubes:
• These paired structures connect each ovary to the uterus
• The ovaries:
• One on each side of the uterus. A normal adult ovary is about the size of an unshelled almond
• Female organs during a pelvic examination