Megacolon

Megacolon is an abnormal dilation of the colon (also called the large intestine). This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. In more extreme cases, the feces consolidate into hard masses inside the colon, called fecalomas, which can require surgery to be removed. A human colon is considered abnormally enlarged if it has a diameter greater than 12 cm (4.7 in) in the cecum (it is usually less than 9 cm [3.5 in]), greater than 6.5 cm (2.6 in) in the rectosigmoid region and greater than 8 cm (3.1 in) for the ascending colon. The transverse colon is usually less than 6 cm (2.4 in) in diameter. A megacolon can be either acute or chronic. It can also be classified according to cause.