Achalasia shows a classic deformity on barium swallow. What is this deformity commonly described as?

• A. Bird's beak
• B. Corkscrew esophagus
• C. Rat-tail sign
• D. Narrowed esophageal stenosis

Answer: (A)

Achalasia on barium swallow produces a dilated esophagus with a smooth, abrupt tapering at the lower end where the gastroesophageal junction resists relaxation—the classic bird’s beak appearance. This happens because the esophageal body lacks peristalsis and the lower esophageal sphincter fails to relax, so food and saliva accumulate above the LES while the distal lumen narrows to a point. The corkscrew pattern is seen with diffuse esophageal spasm, not achalasia, reflecting uncoordinated contractions rather than a single distal tapering. A generic narrowed stenosis lacks the characteristic proximal dilation and smooth distal taper, and the rat-tail sign is not the standard description for achalasia.