Which of the following conditions could cause tenderness in the right upper quadrant?

Tenderness in the right upper quadrant is often associated with conditions affecting organs in that region, particularly the liver and gallbladder. Cholecystitis, which is the inflammation of the gallbladder, frequently presents with localized pain in the right upper quadrant. This condition is often due to gallstones obstructing the cystic duct, leading to bile accumulation and inflammation. Patients typically experience sharp, severe pain that may radiate to the shoulder or back.

In contrast, while colitis can cause abdominal discomfort, it generally affects more of the lower abdomen. Pneumonia may present with referred pain to the abdomen, but it most commonly causes pain in the chest region and is usually accompanied by respiratory symptoms. Aortic dissection primarily causes severe pain in the chest or back and would not typically localize to the right upper quadrant. Understanding the anatomical placement of the gallbladder and its pathophysiological responses helps clarify why cholecystitis is the condition most strongly associated with tenderness in that area.