The fallopian tube is divided into three regions - infundibulum, ampulla and isthmus. The funnel-shaped region of fallopian which is closer to the ovary is called the infundibulum. The region of the fallopian tube which is closer to the uterus is called the isthmus. The region between the infundibulum and isthmus is called the ampulla. The ovum moves from the infundibulum to the isthmus through the ampullary region. Therefore, if the ampulla is blocked, the ovum cannot move from infundibulum to isthmus.