Which one of the following aids is helpful in the diagnosis of bowel strangulation?

Steady severe pain without quiescent periods is usually indicative of strangulation. In non strangulated obstruction of intestine there ma be an area of localized tenderness at the site of obstruction; in strangulation there is always localized tenderness associated with rigidity/rebound tenderness. Rest of three conditions may be present in both obstruction as well as strangulation. The presence of shock indicates ischaemia of bowel. In strangulation pain is never completely absent. Remember the following important points about intestinal obstruction and strangulation: - Four cardinal symptoms and signs of intestinal obstruction are crampy abdominal pain, vomiting, obstipation and abdominal distention. The finding of localized tenderness, fever, tachycardia and leukocytosis are supportive of: but not diagnostic for strangulation.