These findings remark the importance of detecting typical findings of pneumoperitoneum and his differential diagnosis with pseudopneumoperitoneum (basal linear atelectasis, pneumomediastinum, Chilaiditi syndrome, diaphragmatic undulation, gas within skin folds, biliary, portal vein or bowel wall gas, fat within the subdiaphragmatic space or the ligamentum teres, properitoneal fat stripe).

Remember, an erect chest x-ray is the most sensitive plain radiograph for the detection of free intraperitoneal gas.