Final answer:
The most definitive way to distinguish between a contusion and a fracture is through medical imaging like an X-ray, as it can be difficult to differentiate between the two based on symptoms alone.
Step-by-step explanation:
The question asks what is a sure fire way to distinguish between a contusion and a fracture. A contusion, often referred to as a bruise, is characterized by skin discoloration due to blood pooling under the surface, resulting from the impact of a blunt object. The onset of bruising may or may not be immediate, and while painful, it does not involve a break in the bone. In contrast, a fracture represents a break in the bone, which can be complete or partial, such as a crack. It's a misconception that fractures always lead to the inability to move the affected limb or are accompanied by a bruise.
The most definitive way to differentiate a fracture from a contusion is through medical imaging such as an X-ray, which can identify even subtle fractures. Clinical examination focusing on pain, swelling, and the ability to bear weight or use the affected limb can provide clues but imaging is essential for a accurate diagnosis. Without imaging, it can be challenging to distinguish between a severe contusion and a minor fracture as symptoms can overlap.