An 11-year-old boy presented to the emergency department with sudden-onset, severe, sharp, right upper quadrant abdominal pain and vomiting. On examination, the patient was afebrile, with a pulse rate of 92 beats/min and right upper quadrant tenderness. Laboratory test results were unremarkable, including a WBC count of 9,670/mm 3 without left shift. Radiography of the abdomen revealed no evidence of obstruction. Abdominal point-of-care ultrasonography was performed (Figures 1 and 2, left panel, and Video E1, available online at http://www.annemergmed.com) and the diagnosis was confirmed by contrast-enhanced computed tomography (CT) (Figures 1 and 2, right panel).For the diagnosis and teaching points, see page 468. To view the entire collection of Images in Emergency Medicine, visit www.annemergmed.com