Among the most useful modern instruments are endoscopes. Endoscopy instruments enable doctors to examine the interior of the body, usually through a natural body opening, by inserting a lighted optical tube into the cavity. An endoscope contains bundles of fine glass fibers, along which light can be transmitted regardless of how much the fibers are bent. There are at least two bundles of these fibers. One transmits light to illuminate the organ being examined deep inside the body. The other has a lens at the end, which carries light from the organ to an eyepiece.


In addition to the bundles of optical fibers, the shaft of an endoscope carries various tubes and wires. An air pipe allows air to be passed into the area being examined in order to inflate it, making the examination easier. Another pipe can suck out liquids, and there are wires to control the direction in which the tip of the endoscope points. These are operated by controls near the eyepiece.

Endoscopes are often used to diagnose illness. They can be used to examine the insides of many body cavities, such as the stomach, intestines, womb, nose and even joints. Equipped with the right tools, such as forceps and scissors, they can be used to remove tissue for testing. They can even perform small operations, such as the removal of unwanted growths on the wall of the intestine, or the removal of gallstones. Using a powerful laser, it is possible to stop internal bleeding by sealing off the broken blood vessels. With more endoscope operations possible than ever, the need for major surgery is going away in a number of cases.