From Greek: para allelois beside one another. Lines are parallel if they lie in the same plane, and are the same distance apart over their entire length. Try this Drag any orange dot at the points P or Q. As the line PQ moves, the line RS will remain parallel to it. Parallel lines remain the same distance apart over their entire length.
It is important to know whether the cancer has got into the lymph glands because they are one of the main mechanisms by which the cancer can spread to other parts of the body. As long as the spread is just to the lymph glands near to the colon then this would indicate Stage 3 cancer.
Blood supply to the colon. The key to understanding the common colonic resections for cancer is the anatomy of the blood supply to the colon. Resection of the tumor is accomplised en-bloc with resection of the draining lymph nodes. These lymph nodes are arranged along the blood vessels supplying the colon.