What clinical sign is characterized by pain with internal rotation of a flexed right thigh, indicative of appendicitis?

The correct answer highlights the obturator sign, which is specifically associated with appendicitis. This clinical sign is observed when there is pain upon internal rotation of a flexed thigh. During the examination, when a clinician flexes the patient's hip and rotates the thigh inward, irritation of the obturator internus muscle can occur. This irritation reflects the inflammatory process associated with an inflamed appendix, which may be in close proximity to the muscle.

The presence of this sign can suggest appendicitis, particularly when the appendix is located in certain positions, such as the retrocecal space. Therefore, the clinical relevance lies in the association between the obturator sign and appendicitis due to this muscular interaction and the signs of inflammation it may evoke during physical examination.

Other signs listed, such as Rosing's sign, Murphy's sign, and rebound tenderness, have distinct clinical implications or relate to different conditions. For instance, Murphy's sign is specifically indicative of cholecystitis, while rebound tenderness suggests peritonitis rather than being directly linked to appendicitis. Thus, the obturator sign remains the most relevant and diagnostic sign for the context of suspected appendicitis in this scenario.