Endoscopy, upper
A common type of endoscopy is upper endoscopy, also called esophagogastroduodenoscopy (EGD).
In this procedure, a thin flexible instrument is advanced through the mouth to evaluate or treat problems of the esophagus, stomach, and beginning part of the small intestine.
Endoscopy itself is a broad term used to described examining the inside of the body using an lighted, flexible instrument called an endoscope.
In general, an endoscope is introduced into the body through a natural opening such as the mouth in the case of upper endoscopy.