**Double Bubble Sign**

**Core Concept**
The double bubble sign is a radiological finding typically observed in the abdominal X-ray or ultrasound of infants, which indicates an obstruction in the gastrointestinal tract, particularly in the duodenum. It is characterized by the presence of two gas-filled structures, resembling bubbles, in the upper abdomen.

**Why the Correct Answer is Right**
The double bubble sign is due to the accumulation of gas in the stomach and the proximal part of the duodenum, resulting from an obstruction in the duodenum. The obstruction prevents the normal flow of intestinal contents, leading to the accumulation of gas and fluid proximal to the obstruction. This sign is often seen in conditions such as duodenal atresia, duodenal stenosis, or pyloric stenosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the double bubble sign is not typically associated with pancreatic disorders, such as pancreatitis or pancreatic cancer, which may present with different radiological findings.
* **Option B:** This option is incorrect because the double bubble sign is not a characteristic finding in liver diseases, such as hepatitis or cirrhosis, which may present with different radiological findings.
* **Option C:** This option is incorrect because the double bubble sign is not a typical finding in appendicitis, which may present with different radiological findings, such as appendicolith or appendiceal wall thickening.

**Clinical Pearl / High-Yield Fact**
The double bubble sign is a classic radiological finding in duodenal atresia, a congenital anomaly that occurs in approximately 1 in 10,000 births. It is essential to recognize this sign in infants to avoid delayed diagnosis and treatment.

**Correct Answer:** C.