This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Gynae), Subject name: Gynaecology & Obstetrics
Which will not come between cytotrophoblast and maternal blood? 
Select and explain. 
A. Decidua parietalis, B. Syncytiotrophoblast, C. Inter villous space, D. Basement membrane
A: Decidua parietalis
Answer: A: Decidua parietalis 
Explanation: Ans: a (Decidua parietalis) Ref: Dutta, 6th ed, 31As seen clearly from the diagram, the decidua parietalis is situated away from the attatchment of the embryo and thus cannot come between the maternal blood and cytotrophoblast.