Most medical professionals use the Wallace Rule of Nines (more commonly referred to simply as the Rule of Nines), a tool to estimate the total body surface area affected by a burn. Medical professionals can quickly calculate how much of the body was affected by looking at the respective percentage value assigned to that region of the body for the adult or child on the Rule of Nines chart. The chart’s name is reflective of the majority of the body parts listed having 9 percent body surface area damage, although an entire back or one leg represents 18 percent and a groin burn is 1 percent.