In the pediatric Rule of Nines, what percentage is assigned to one arm?

• A. 4.5%
• B. 9%
• C. 7%
• D. 18%

Answer: (B)

The main idea is quick estimation of burn size using fixed body-region percentages. In this framework, one arm is 9% of the total body surface area, with 4.5% on the front (anterior) and 4.5% on the back (posterior). In children, head size changes with age, so for precise calculations clinicians use age-adjusted charts like Lund Browder, but the arm’s share stays 9% per arm in the Rule of Nines approach. Therefore, the correct value for one arm is nine percent. The other options don’t fit because 4.5% would be only half an arm, 18% would correspond to a larger region (like a full leg) or combination, and 7% isn’t a standard proportion for a single arm.