What physical exam finding may indicate the presence of gallstones?

Murphy's sign is a physical exam finding that specifically indicates potential issues with the gallbladder, particularly the presence of gallstones or cholecystitis. When performing this test, a healthcare provider palpates the right upper quadrant of the abdomen while asking the patient to take a deep breath. If the patient experiences pain and abruptly stops inhaling due to tenderness when the gallbladder is assessed, this is considered a positive Murphy's sign. The mechanism behind this reaction involves the gallbladder being inflamed or irritated by gallstones, thus eliciting a painful response during deep inspiration.

The other options do not directly correlate with gallstones. Pallor may indicate anemia or shock, tachycardia can result from various conditions including stress or anemia, and lightheadedness is a non-specific symptom that could stem from numerous causes. None of these findings provide a targeted examination focus on gallbladder-related issues like Murphy's sign does, making the latter the key indicator in this clinical context.