<prompt> How to differentiate mechanical obstruction from paralytic ileus?Elevation of hemi diaphragmAbsence of rectal shadowMultiple air fluid levelsAbdominal distension  <response>: Ans. b Absence of rectal shadowRef: Bailey and Love 26th edition, Page 1190 The important point to differentiate paralytic ileus and mechanical obstruction in X-ray is there will be absence of rectal gas shadow in mechanical obstruction. Clinically bowel sounds will be absent in paralytic ileus with no pain. 