This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
30-year-old patient with acute abdomen pain with obstipation. X-ray given below. Diagnosis? 
Select and explain. 
A. Small bowel obstruction, B. Large bowel obstruction, C. Gastric outlet obstruction, D. Duodenal atresia
A: Small bowel obstruction
Answer: A: Small bowel obstruction 
Explanation: Ans. (a) Small bowel obstructionRef: Bailey and Love 26th edition, Page 1189* Nowadays for suspected small bowel obstruction erect X-ray is not done unless specifically required* This X-ray shown here is X-ray abdomen erect -- showing multiple air fluid levels in stepladder pattern* Supine X-ray shows more of gas filled small bowel loops* Erect X-ray shows air fluid levels with air at the top and fluid below* 2-5 air fluid levels are normal.