Definition
Cancer of the colon is the disease characterized by the development of malignant cells in the lining or epithelium of the first and longest portion of the large
Colon cancer
intestine. Malignant cells have lost normal control mechanisms governing growth. These cells may invade surrounding local tissue or they may spread throughout the body and invade other organ systems.
Synonyms for the colon include the large bowel or the large intestine. The rectum is the continuation of the
large intestine into the pelvis that terminates in the anus.
Description
The colon is a tubular organ beginning in the right lower aspect of the abdomen. Anatomically, it ascends on
the right side of the abdomen, traverses from right to left in the upper abdomen, descends vertically down the left
side, takes an S-shaped curve in the lower left abdomen, and then flows into the rectum as it leaves the abdomen
for the pelvis. These portions of the colon are named separately though they are part of the same organ.
• cecum, the beginning of the colon
• ascending colon, the right vertical ascent of the colon
• transverse colon, the portion traversing from right to left
• descending colon, the left vertical descent of the colon
• sigmoid colon, the s-shaped segment of colon above the pelvis
