What is the Rule of the Nines proportion for the head in burn injuries?

• A. An anterior torso 18%
• B. Head 9%
• C. Arms 9% each
• D. Genitals 1%

Answer: (B)

In burn assessment, the Rule of Nines quickly estimates total body surface area burned by assigning percentages to major body regions. For an adult, the head and neck together account for 9% of the total body surface area. That means burns limited to the head represent about one-tenth of a person’s body surface area. The rest of the body is divided into other regions with their own percentages (arms 9% each, anterior trunk 18%, posterior trunk 18%, legs 18% each, genitals 1%), which together sum to 100%. Note that in children the head represents a larger share of TBSA, but in adults the head is 9%.