The cecum is the first section of the large intestine. In humans, it does not serve a specific purpose, and it is possible for a human to live without a cecum.
The appendix connects to the cecum. Like the cecum, the appendix is not necessary for healthy digestive function in humans. The cecum and appendix are the regions of the large intestine least vulnerable to colon cancer, but cancers in these areas are more difficult to detect than the more common forms of colon cancer.
Besides rare instances of cecal cancer, other health concerns involving the cecum are intestinal blockage, inflammatory bowel disease and appendicitis. Blockage occurs when the cecum twists and obstructs food from passing further along the digestive system. It can be caused by severe coughing, pregnancy and abdominal scar tissue, and is most common in young and middle-aged adults.
In herbivores, the cecum is used to digest cellulose. This adaptation no longer exists in humans, who cannot digest insoluble plant fibers. Birds and some herbivorous mammals have two cecums, and there is scientific debate as to whether or not the appendix is a remnant of this second cecum. Fish, amphibians and some carnivorous mammals completely lack a cecum.