fallopian tube
Summary
The fallopian tubes (uterine tubes/oviducts) are paired muscular ducts that transport the oocyte from the ovary to the uterus and are the typical site of fertilization. They consist of four segments: infundibulum (with fimbriae), ampulla (most common site of fertilization and ectopic pregnancy), isthmus, and intramural (interstitial) portion. They are derived embryologically from the paramesonephric (Müllerian) ducts.
Detail
The fallopian tubes extend laterally from the uterine cornua to the ovaries within the mesosalpinx (part of the broad ligament). Histologically, the mucosa has ciliated and secretory (peg) cells; ciliary beating and peristaltic contractions move the oocyte/embryo toward the uterus. Estrogen promotes ciliogenesis, while progesterone affects tubal motility.
Embryology: derived from paramesonephric (Müllerian) ducts; failure of fusion or regression of mesonephric remnants can cause anomalies (e.g., duplication, atresia) or paratubal (hydatid) cysts.
Blood supply: ovarian and uterine arteries (anastomosing tubal branches). Lymphatic drainage follows ovarian vessels to para-aortic nodes.
Clinical significance: - Ectopic pregnancy: >95% of ectopic pregnancies occur in the fallopian tube, most commonly the ampulla; risk factors include prior PID, tubal surgery, endometriosis, and smoking. Presents with amenorrhea, abdominal pain, and vaginal bleeding; rupture can cause life-threatening hemoperitoneum. - Pelvic inflammatory disease (PID): ascending infection (commonly Chlamydia trachomatis, Neisseria gonorrhoeae) causes salpingitis, which can lead to tubal scarring, infertility, and increased ectopic pregnancy risk (Fitz-Hugh-Curtis syndrome if perihepatic involvement). - Hydrosalpinx: fluid-filled dilation of the tube secondary to distal obstruction, often post-infectious; associated with infertility. - Tubal ligation: common method of permanent contraception; site of many surgical procedures (salpingectomy, salpingo-oophorectomy). - Origin of high-grade serous ovarian/tubal carcinoma: increasing evidence indicates many so-called 'ovarian' high-grade serous carcinomas actually arise from the fimbrial epithelium of the fallopian tube (via serous tubal intraepithelial carcinoma, STIC lesions), relevant for BRCA-associated risk-reducing salpingo-oophorectomy.
Key associations for boards: ampulla = most common ectopic site; PID/Chlamydia = leading cause of tubal infertility; STIC lesions = precursor to serous ovarian cancer.
Sources
- Moore's Clinically Oriented Anatomy
- Langman's Medical Embryology
- First Aid for the USMLE Step 1
- Robbins Basic Pathology
- Williams Gynecology
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.