![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyyh-A4a9GALE18N-3bIrlYtcHUpdOJKBCHnSmvNxmt-dx3sks_TLjPEFyLQNaS70iUqdSc_EKaQeDdWPr2KNTMsCEbXyGETSq986chZ3MZTsfnEF0AyCTF4tBRGeVLNyWYPQeqRlnsuHC/s400/untitled.bmp)
It appeares as :Hemispherical or horizontal, shelflike protrusion on the posterior aspect of the esophagus at approximately the C5-C6 level.
Short Comment.......It is Failure of the upper esophageal sphincter to relax. Can result in dysphagia by obstructing the passage of a swallowed bolus. In severe disease, can cause aspiration and pneumonia.