Final answer:
A spoon splint is used to stabilize the radius, which is the most commonly fractured forearm bone, often from falls onto an outstretched hand such as in a Colles fracture.
Step-by-step explanation:
The bone that can be stabilized using a spoon splint is the radius. Spoon splints are designed to support the natural curve of forearm bones and are typically used for forearm fractures, including those of the radius and ulna. Since the radius is the most common forearm fracture, often resulting from falls onto an outstretched hand such as a Colles fracture of the distal radius, it is the bone most frequently stabilized with a spoon splint. These fractures can cause the articulating surface of the radius to become rough or jagged, making movements painful. Splints, in addition to other treatments like surgery, help provide stability and promote healing. The other options listed (scapula, humerus, femur) are not commonly treated with a spoon splint.