A hollow pouch sometimes found attached to the small INTESTINE about 90–120 cm (3–4 feet) from its junction with the large intestine. It is several centimetres long, and ends blindly. It is lined with cells similar to those which line the stomach, and these may produce acid thereby leading to illness – Meckel's diverticulitis with ulceration, which causes abdominal pain and fever (sometimes referred to as ‘left-sided appendicitis’). Perforation may result in PERITONITIS and, rarely, may be the lead point of an INTUSSUSCEPTION.