This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Maternal Anatomy and Physiology, Subject name: Gynaecology & Obstetrics
Shoest and narrowest pa of fallopian tube: 
Select and explain. 
A. Interstitial, B. Isthmus, C. Ampulla, D. Infundibulum
A: Interstitial
Answer: A: Interstitial 
Explanation: Pas of the fallopian tube Interstitial pa: shoest, internal diameter 1mm (narrowest) Isthmus:35 mm long, lumen diameter 2-3 mm Ampulla: 60-75 mm long, widest . Feilisation takes place here Infundibulum: where abdominal ostium opens into the peritoneal cavity