A plain X ray abdomen is performed in case of small bowel obstruction. Small bowel would be called dilated if its diameter is more than:
Normal bowel caliber: Small bowel- <3 cm Large bowel- <6 cm Caecum- <9 cm Thus, small bowel is called dilated if its caliber is >3 cm.
2 cm
3 cm
4 cm
5 cm
Intestinal obstruction