Overview
Four Segments, Four Different Clinical Implications
The paired fallopian tubes, also called uterine tubes or oviducts, extend from the uterine cornua toward the ovaries.
The paired fallopian tubes, also called uterine tubes or oviducts, extend from the uterine cornua toward the ovaries. Each is approximately 10–12 cm long. The ovary is not directly attached to the tube; at ovulation, the distal end must capture the oocyte as it is released into the peritoneal cavity. From medial to lateral, the tube has four segments: - Interstitial, or intramural: the short segment passing through the uterine wall. An interstitial ectopic lies within the myometrium, close to substantial uterine blood vessels, so rupture can cause severe hemorrhage. - Isthmus: the narrow, muscular segment between the interstitial portion and the ampulla. It is a common site of tubal occlusion during sterilization. - Ampulla: the widest and longest segment and the usual site of fertilization. It is also the most frequent site of tubal ectopic implantation. - Infundibulum: the funnel-shaped distal end, whose fimbriae sweep near the ovary and help guide the oocyte into the tubal opening. A population-based series of 1800 ectopic pregnancies found implantation in the ampulla in approximately 70%, the isthmus in 12.0%, the fimbrial region...