Colon diverticula. Coloured X-ray of part of the abdominal region of a patient with diverticulosis. Small pouches called diverticula (green) can be seen in the sigmoid region of the colon (pink). This is the region of the colon that connects to the rectum. The formation of diverticula in the colon lining is thought to be linked to a low- fibre diet, and they are very common in the elderly. Usually, there are no symptoms, although some may cause abdominal cramps and constipation or diarrhoea. The patient was given a barium meal to render the colon opaque to X-rays.