Which of the following is a sign of a closed fracture?

Swelling and discoloration are common signs associated with a closed fracture. A closed fracture refers to a break in the bone where the skin remains intact, meaning there are no open wounds or exposure of the bone to the environment. When the fracture occurs, it can lead to swelling due to inflammation and tissue response around the injury site. Discoloration, often manifesting as bruising, results from bleeding under the skin as a consequence of the fracture and subsequent soft tissue damage.

The other options listed are indicative of other conditions or types of injuries. For example, bones sticking through the skin are characteristic of an open fracture, while external bleeding can occur with various injuries, not specific to fractures. Loss of consciousness may suggest a more severe injury or trauma unrelated to the fracture itself. Thus, swelling and discoloration distinctly align with the signs of a closed fracture.