Reverse 3 sign in barium swallow is seen in:
**Core Concept**
The "reverse 3 sign" in a barium swallow study refers to a characteristic radiographic pattern observed in the esophagus. This sign is associated with a specific type of esophageal pathology that affects the normal peristaltic motion of the esophagus.
**Why the Correct Answer is Right**
The reverse 3 sign is typically seen in achalasia, a disorder of the esophagus characterized by the absence of peristalsis and failure of the lower esophageal sphincter (LES) to relax. The esophagus becomes dilated, and the LES remains contracted, preventing the normal passage of food into the stomach. The reverse 3 sign is a result of the abnormal contraction of the esophageal body, creating a "3" shape on the barium swallow radiograph.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the "bird beak" sign is typically associated with esophageal strictures, not achalasia.
* **Option B:** This option is incorrect because the "rat tail" sign is associated with diffuse esophageal spasm, a different condition from achalasia.
* **Option C:** This option is incorrect because the "double-contrast" sign is associated with esophageal varices, which are not directly related to the reverse 3 sign.
**Clinical Pearl / High-Yield Fact**
Achalasia is often associated with dysphagia, regurgitation, and weight loss. It is essential to distinguish achalasia from other esophageal disorders, such as esophageal cancer, using a combination of clinical evaluation, barium swallow studies, and manometry.
**Correct Answer:** C. Achalasia.