This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Uterine Tubes, Subject name: Gynaecology & Obstetrics
Longest part of fallopian tube? 
Select and explain. 
A. Ampulla, B. Isthmus, C. Intramural, D. Fibriae
A: Ampulla
Answer: A: Ampulla 
Explanation: Ans. a (ampulla). (Ref. Williams, Obstetrics, 21st ed., 46)FALLOPIAN TUBE# Fallopian tube has following parts;- interstitial/intramural part,- isthmus,- ampulla,- fimbria.# An intermediate zone, the isthmus, 6 mm in length, lies between endometrium of the body and the mucous membram of the cervical canal.# The isthmic portion forms the lower uterine segment in late pregnancy.# Narrowest part of uterine tube is interstitial portion.# The ampulla:- Is the lateral, widest and lowest part of the tube and comprises roughly two-thirds of the tube.- Here the mucosa is arborescent with many complex folds.- Is the most common site of fertilization.- Is the most common site of tubal pregnancy.