## **Core Concept**
The question assesses knowledge of the proportion of body surface area (BSA) affected by burns in infants, specifically focusing on head and neck burns. In pediatric patients, the Lund-Browder chart is often used to estimate the BSA burned, as the proportion of body surface area changes with age.

## **Why the Correct Answer is Right**
In infants, the head and neck area constitutes a larger proportion of the total body surface area compared to adults. According to the Lund-Browder chart, in children under 1 year, the head and neck area is approximately 18% of the total BSA. This estimation is crucial for fluid resuscitation and management of burns in pediatric patients.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 9% is the proportion often used for the head and neck in adults, not in infants.
- **Option B:** 11% might be an underestimation for infants; it does not accurately reflect the proportion used for head and neck burns in this age group.
- **Option D:** 25% could be considered an overestimation for the head and neck area in infants.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the percentage of body surface area affected by burns in children differs significantly from adults. The Lund-Browder chart provides a more accurate estimation for children, with the head and neck area being about 18% in infants. This is crucial for calculating fluid requirements and assessing the severity of burns.

## **Correct Answer:** . 18%