Small bowel is distended more than 2.5cm outside diameter, and collapsed ascending colon (black arrowhead in Fig.5-Fig.8) is indicative of mechanical obstruction. Right colon is filled with liquid content similar to small bowel for most cases of paralytic ileus. Ascites (reference mark) in Fig.1, Fig.20 and Fig.21 and gasless distended small bowel suggest strangulation, but absence of mesenteric stranding and well contrast-enhanced wall suggest simple obstruction. In order to differentiate possibilities between paralytic ileus and simple obstruction, start tacking down distended small intestine from 1 and A of Fig.19. 1 makes progress to 10 of Fig.2 and continues to go up. On the other hand, A occludes at H of Fig.6, and there is an adjacent collapsed small bowel (SB), and black arrow indicates transition zone. ab of Fig.3 is divided into a and b of Fig.2 and go up to cephalad side without connecting with 6 of Fig.4. No other obstruction point in adjacent area of H of Fig.6 rules out strangulated obstruction. Obstruction directly beneath midline incision suggests adhesive obstruction. Conservative treatment by ileus tube was performed with success.