<prompt> In Plummer-Vinson syndrome, the region involved isPosterior pharyngeal wallValleculaePostcricoid regionPyriform sinus  <response>: Plummer-Vinson syndrome PVS, a rare clinical condition, is characterized by a triad of dysphagia, iron deficiency anemia and esophageal web in the post-cricoid region. Ref ganongs review of medical physiology 25e 676 