Endoscopy Bending Sections

The bending section is composed of a series of oddly-shaped metal rings, each one connected to the ring on either side of it via a freely moving joint. These joints are constructed using a series of pivot pins, each one displaced from its neighbors by 90 degrees. 

One set of pivots allows the bending section to curl in the up-and-down direction. A second set allows the bending section to curl in the right-and-left direction. Together, they enable the bending section to curl in any direction. The direction of the curl is controlled by four angulation wires that run the length of the insertion tube. These four wires are firmly attached to the tip of the bending section at the 3 o’clock, 6 o’clock, 9 o’clock, and 12 o’clock positions. Pulling on the wire attached at the 12 o’clock position causes the bending section to curl in the up direction and achieves what endoscopists refer to as “up tip deflection.” Pulling on the wire attached at the 3 o’clock position causes right tip deflection. Pulling the other two wires causes down and left deflection. The endoscopist is able to pull on each of these wires in turn by rotating either the up-and-down or right-and-left angulation knobs. Rotating the up-and-down and right-and-left knobs together produces a combined tip movement (e.g., upward and to the right) and allows the endoscopist to sweep the tip of the endoscope in any direction.