n. a flexible optical endoscope using digital video technology to visualize and sample the interior of the bile ducts.
n. a semirigid plastic tube (25–45 cm long) designed to fit over the shaft of an *endoscope in order to minimize the risk of trauma. It can be used with a *gastroscope, *cholangioscope, *enteroscope, or colonoscope (see colonoscopy). An overtube is placed over the shaft of an endoscope prior to its insertion; once the endoscope is in the desired place, the overtube is lubricated and slid into position over the shaft. It is commonly used in combination with a gastroscope for the removal of ingested foreign bodies (especially those with sharp or serrated edges that may cause significant trauma as they are being extracted).... overtube