<prompt> Barium swallow is used forEsophagusColonDuodenumJejunum  <response>: The esophagus is a muscular tube connecting the throat pharynx with the stomach.The esophagus is about 8 inches long and is lined by moist pink tissue called mucosa.The esophagus runs behind the windpipe trachea and heart, and in front of the spine. 