## **Core Concept**
Rickets is a disease caused by vitamin D deficiency, leading to softening of bones in children. The healing process involves changes in bone metabolism and density. Early signs of healing can be detected through radiological investigations.

## **Why the Correct Answer is Right**
The correct answer, , shows the earliest evidence for healing in rickets. During the healing process, the first radiological sign is the appearance of a **"double density"** or **"ring around the wrist"** due to increased density around the growth plates. This occurs before more pronounced changes like the metaphyseal "cupping" and "fraying" resolve. The increased density is due to the initial deposition of calcium and phosphorus in the growth plates.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option does not accurately represent the earliest sign of healing in rickets.
* **Option B:** This option might show changes in bone density but is not the earliest indicator.
* **Option D:** This option might represent a later stage of healing or a different aspect of bone health.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **"Trümmerfeld zone"** or **"growth plate"** changes are critical in diagnosing and monitoring the treatment of rickets. Early detection of healing can prevent progression to more severe bone deformities.

## **Correct Answer:** . widening of growth plate.