This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Structure crossing dorsal surface of ischial spine are all except 
Select and explain. 
A. Internal pudendal vessel, B. Pudendal nerve, C. Obturator nerve, D. Nerve to obturator internus
C: Obturator nerve
Answer: C: Obturator nerve 
Explanation: Pudendal nerve, internal pudendal vessels, and nerve to obturator internus after leaving the pelvis through greater sciatic foramen, cross the dorsal aspect of the ischial spine and then re-enter the pelvis through the lesser sciatic foramen.