Gynaecology & Obstetrics All except one is true regarding fallopian tube A Fertilization occurs in ampullary portion of fallopian tube B There are no longitudinal muscle fibres in interstitial portion of tube C It has 2 sources of blood supply D Isthmus in narrower portion of fallopian tube. 💡 Explanation All except one is true regarding fallopian tube ✓ Correct Answer: D. Isthmus in narrower portion of fallopian tube.