This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
Most dependent pa of abdomen in standing position is 
Select and explain. 
A. Vesicouterine pouch, B. Pouch of douglas, C. Morrison pouch, D. Left paracolic gutter
B: Pouch of douglas
Answer: B: Pouch of douglas 
Explanation: The recto-uterine pouch (cul-de-sac or pouch of Douglas) is the extension of the peritoneal cavity between the rectum and the posterior wall of the uterus. It is the most inferior aspect of the peritoneal cavity and therefore the first location where free fluid accumulates . ref - BDC 6e vol2 pg244