**Core Concept**
Toddler fractures are a type of non-accidental injury, often occurring in children between the ages of 9 months and 3 years. They typically involve spiral fractures of the long bones, particularly the tibia, due to twisting forces.

**Why the Correct Answer is Right**
Spiral fractures are characteristic of toddler fractures because they result from a twisting motion, which is consistent with the type of injury that a child might suffer if they are being manipulated or twisted. This mechanism of injury is distinct from the typical accidental injuries that occur in children, such as falls or direct blows. The spiral pattern of the fracture is a key diagnostic clue, as it suggests a twisting force rather than a direct impact.

**Why Each Wrong Option is Incorrect**
**Option A:** Subluxation of the radial head is a type of injury that can occur in young children, but it is not characteristic of toddler fractures. Subluxations typically result from a direct blow or fall, rather than a twisting motion.
**Option B:** Salter Harris type 3 fractures are growth plate injuries that can occur in children, but they are not specific to toddler fractures. These fractures involve a separation of the growth plate from the metaphysis, and can occur in response to a variety of mechanisms of injury.
**Option C:** Fractures of the distal radius can occur in children, but they are not typically associated with toddler fractures. The distal radius is a common site for fractures in children, but the mechanism of injury is often a direct fall onto the outstretched hand rather than a twisting motion.

**Clinical Pearl / High-Yield Fact**
Toddler fractures should raise suspicion for non-accidental injury, particularly if there are other signs of abuse or neglect present. A high index of suspicion and a thorough investigation are essential in these cases, as they can have significant implications for the child's safety and well-being.

**✓ Correct Answer: D. Spiral fracture of the tibia**