<prompt> Bird beak sign on barium swallow is seen in?Achlasia cardiaCarcinoma esophagusHiatus herniaNut cracker esophagus  <response>: Ans. is a i.e., Achlasia cardia Bird beak appearance on barium study is seen in achlasia cardia.Important esophageal signs on radiographySignConditionRat tail appearance of esophagusEsophageal carcinomaMega-esophagus sigmoid esophagusBird beak appearanceHurst phenomenonAchlasia cardiaYo-Yo motion of bariumCorkscrew appearance esophageal curlingRosary-beadsheikh kebab configurationChain of bead appearanceDiffuse esophageal spasm 