Flexible endoscopes provide either an optical image(transmitted over fiber optic bundles) or an electronic video image(generated by a charge-coupled device in the tip of the endoscope. Operator controls permit deflection of the endoscope tip; fiber optic bundles bring light to the tip of the endoscope; and working channels allow washing, suctioning, and the passage of instruments. Progressive changes in diameter and stiffness of endoscopes have improved the ease and patient tolerance of endoscopy.

The endoscopic procedures are Upper Endoscopy, also refered to as esophagogastroduodenoscopy (EGD); Colonoscopy, performed by passing a flexible colonoscope through the anal canal into the rectum and colon; Flexible Sigmoidoscopy, is similar to colonoscopy but visualizes only the rectum and a variable portion of the left colon; Entoroscopy, is the relatively new field of small bowel endoscopy, two techniques are “Push” enteroscopy and “Sonde” enteroscopy; Endoscopic Retrograde Cholangiopancreatography (ERCP); and Endoscopic Ultrasound (EUS).