Final answer:
The specific assessment finding for hemothorax is dullness to percussion, as it indicates the presence of blood in the pleural cavity, distinguishing it from the hyperresonance typically found in pneumothorax.
Step-by-step explanation:
The assessment finding specific to hemothorax rather than pneumothorax is D. Dullness to percussion. Hemothorax is a condition where blood accumulates in the pleural cavity, causing dullness due to the presence of fluid. In contrast, a pneumothorax, which is air in the pleural cavity, typically presents with hyperresonance to percussion. Other symptoms such as chest or shoulder pain, diminished or absent breath sounds, and tachypnea are common to both conditions and are not specific in differentiating between the two.