This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Radiology
Windsock appearance on barium is seen in? 
Select and explain. 
A. Duodenal perforation, B. Duodenal ulcer, C. Brunner gland hyperplasia, D. Internal duodenal diverticulum
D: Internal duodenal diverticulum
Answer: D: Internal duodenal diverticulum 
Explanation: Ans DWindsock appearanceQ is intraduodenal barium contrast- filled sac that is surrounded by a narrow lucent line seen in intraduodenal diverticulumQ.