Our colon is not a straight line, so when the surgeon performs a colonoscopy, he or she does
not simply push the tube-like endoscope through the colon. After the endoscope passes
through the rectum, it reaches the curvy sigmoid colon, and the two right-angled turns of
splenic flexure and hepatic flexure are waiting ahead. It is relatively easy to pass through the
first turn, but if the endoscope is being pushed forward at the second or third turn, the
curvature at the first might become too much for the human intestine to hold. In some
cases, the endoscope just cannot proceed forward, and in some extreme cases the bend of
the endoscope might even tear apart tissues of the intestinal wall.
For a smooth colonoscopy, it is important to keep the endoscope as straight as possible.
After the endoscope has passed through a turn of the colon, it is necessary to slightly pull it
backward to reduce the curvature. At the same time, the doctor would remove all gases
inside the colon so that the intestinal wall would tightly enwrap the endoscope. When the
endoscope reaches the end of the colon, the doctor can slowly pull it backward to examine
the mucosa of the intestinal wall. Keeping the endoscope straight also help avoid the
camera at the head moving too fast at the bends, preventing a careful examinations of the
intestinal wall at those turns.
In colonoscopy, precision in the movement of endoscope is the key – every millimetre
counts.