Spectrum of Signs of Pneumoperitoneum.

Pneumoperitoneum is caused by rupture of a hollow viscus that includes the stomach, small bowel, and large bowel, with the exception of those portions that are retroperitoneal in the duodenum and colon. The causes of pneumoperitoneum are numerous, ranging from iatrogenic and benign causes to more life-threatening conditions. In the absence of a benign cause of pneumoperitoneum, the identification of free intraperitoneal gas usually indicates the need for emergency surgery to repair a perforated bowel.