1. All patient had extraluminal free-air and either focal colonic wall defects or fecal spillage.

2. Sigmoid colon is the most frequent site of the spontaneous colonic perforation.

•  due to the special physiological and anatomical features of sigmoid colon

               - no ramus anastomoticus between the lowest branch

                  of sigmoid arteries and the superior rectal artery

                         --> a physiological ischemia

3. Patients are more fetal having necrosis(bowel ischemia) in pathology.

4. Poor vascular supply and fecal impaction can be suggested main cause of spontaneous colon perforation.

• Constipation --> fecal impaction
• DM, CRF, CHF, Liver cirrhosis --> poor vascularity
• Elder patients

Spontaneous perforation of the colon most commonly occurs to the elderly with chronic debilitating underlying diseases, so the mortality and morbidity rate after surgery are high. Sigmoid colon is the most frequent site of the spontaneous colonic perforation, and characteristically colonic wall defects, massive fecal spillage and extraluminal free air are observed on CT scans.