Murphy's sign is a clinical test used to detect inflammation of the gallbladder (cholecystitis). It is performed by asking the patient to inhale while the examiner applies pressure to the right upper quadrant below the costal margin. A positive Murphy’s sign occurs when the patient experiences a sudden stop in inspiration due to pain as the inflamed gallbladder contacts the examiner’s fingers. This finding is highly suggestive of acute cholecystitis and helps differentiate it from other causes of abdominal pain. It is not associated with appendicitis, pancreatitis, or peptic ulcer disease.

Reference: Sabiston Textbook of Surgery, 21st Edition.