This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intestinal obstruction, Subject name: Surgery
True about strangulation of intestine is: 
Select and explain. 
A. Aerial blood flow affected first, B. Usually venous blood flow affected first, C. Blood flow normal, D. No gangrene
B: Usually venous blood flow affected first
Answer: B: Usually venous blood flow affected first 
Explanation: Venous return is compromised before aerial supply in strangulated intestinal obstruction.