A rigid endoscope is a medical instrument used to view the larynx. It is passed through the mouth as opposed to the nasal cavity when a flexible endoscope is used.  It consists of a series of lenses in a rigid metal tube. At the end that goes in the mouth there is either a 70o or 90o prism allowing a view down the throat. A camera can be attached to the eyepiece so that images can be seen on a computer screen or TV monitor.