Which statement accurately describes the Rule of 9's for estimating burn size?

Which statement accurately describes the Rule of 9's for estimating burn size?

• A. Head 9%, Each arm 9%, Each leg 9%, Front torso 18%, Back torso 18%
• B. Head 9%, Each arm 9%, Each leg 18%, Front torso 18%, Back torso 18%
• C. Head 9%, Each arm 9%, Each leg 9%, Front torso 9%, Back torso 9%
• D. Head 9%, Each arm 18%, Each leg 9%, Front torso 18%, Back torso 36%

Answer: (C)

The Rule of 9s estimates burn size by assigning fixed percentages to major body regions so you can quickly gauge the extent. In an adult, the head accounts for 9%, each upper limb accounts for 9%, each lower limb accounts for 18%, the anterior trunk accounts for 18%, and the posterior trunk accounts for 18%, with the perineum making up 1%. These values sum to 100%. If every region were 9%, as some options imply, the legs and trunk would be grossly undervalued (a leg would be counted as 9% instead of 18%, and the trunk regions would also be misrepresented), leading to a wrong estimate of total burn area. So the correct understanding is that legs and trunk regions carry larger shares (18% each for the front and back trunk, and 18% for each leg), while the head and each arm are 9% apiece. This quick framework lets clinicians estimate burn size and prioritize management efficiently.

The Rule of 9s estimates burn size by assigning fixed percentages to major body regions so you can quickly gauge the extent. In an adult, the head accounts for 9%, each upper limb accounts for 9%, each lower limb accounts for 18%, the anterior trunk accounts for 18%, and the posterior trunk accounts for 18%, with the perineum making up 1%. These values sum to 100%.

If every region were 9%, as some options imply, the legs and trunk would be grossly undervalued (a leg would be counted as 9% instead of 18%, and the trunk regions would also be misrepresented), leading to a wrong estimate of total burn area.

So the correct understanding is that legs and trunk regions carry larger shares (18% each for the front and back trunk, and 18% for each leg), while the head and each arm are 9% apiece. This quick framework lets clinicians estimate burn size and prioritize management efficiently.