Using the Rule of Nines, which region accounts for 9% TBSA in an adult?

Using the Rule of Nines, which region accounts for 9% TBSA in an adult?

• A. Chest
• B. Back
• C. Head
• D. Abdomen

Answer: (C)

Rule of Nines is used to quickly estimate burn size by assigning a standard percentage of body surface area to major regions. In adults, the head accounts for 9% of total body surface area, which is why a burn confined to the head totals 9% TBSA. By comparison, the back represents 18% (the entire posterior trunk) and the front trunk (chest and abdomen together) is also 18%, while an arm is 9% and a leg is 18%. This framework helps guide resuscitation calculations, such as fluid needs, in the early transfer to definitive care. Therefore, the head is the region that amounts to 9% TBSA.

Rule of Nines is used to quickly estimate burn size by assigning a standard percentage of body surface area to major regions. In adults, the head accounts for 9% of total body surface area, which is why a burn confined to the head totals 9% TBSA. By comparison, the back represents 18% (the entire posterior trunk) and the front trunk (chest and abdomen together) is also 18%, while an arm is 9% and a leg is 18%. This framework helps guide resuscitation calculations, such as fluid needs, in the early transfer to definitive care. Therefore, the head is the region that amounts to 9% TBSA.