**Core Concept**
The Pelkan spur is a characteristic radiological finding associated with certain bone disorders. It refers to a thin, radiating, or spur-like calcification extending from the growth plate into the metaphysis in children.

**Why the Correct Answer is Right**
The Pelkan spur is a benign calcification seen in the metaphysis adjacent to the growth plate, particularly in the long bones of children. It is thought to be a result of the abnormal deposition of calcium salts in the cartilage and bone matrix. This calcification is often seen in conditions that affect bone growth, such as rickets or osteogenesis imperfecta. The Pelkan spur is a distinctive radiological feature that helps in the diagnosis of these conditions.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the Pelkan spur is not typically associated with fractures or trauma. While fractures can cause various radiological abnormalities, the Pelkan spur is a specific finding related to bone growth and development.
**Option B:** This option is incorrect because the Pelkan spur is not a characteristic feature of osteomyelitis. Osteomyelitis is a bone infection that can cause a range of radiological abnormalities, including soft tissue swelling, bone destruction, and periosteal reaction, but it is not typically associated with the Pelkan spur.
**Option C:** This option is incorrect because the Pelkan spur is not a feature of bone tumors. While bone tumors can cause a range of radiological abnormalities, the Pelkan spur is a specific finding related to bone growth and development.

**Clinical Pearl / High-Yield Fact**
The Pelkan spur is a benign and self-limiting finding that typically resolves with correction of the underlying cause, such as vitamin D deficiency in rickets. It is essential to recognize the Pelkan spur as a normal variant to avoid unnecessary investigations and treatment.

**Correct Answer: C. Osteogenesis imperfecta.**