What is the purpose of the burn extent assessment using the Rule of Nines?

• A. To monitor wound healing
• B. To assess burn depth
• C. To estimate burn surface area
• D. To assess infection risk

Answer: (C)

Estimating burn surface area is the main purpose of the Rule of Nines. It quickly assigns percentages to major body regions so you can approximate the total body surface area burned (TBSA). That TBSA estimate is essential for guiding fluid resuscitation and initial triage decisions in burn care. The Rule of Nines does not tell you how deep the burn is—that requires examining the tissue appearance, sensation, blistering, and thickness. It also doesn’t directly measure infection risk, which depends on wound care, contamination, and overall patient factors. For example, an adult with burns on both legs and the front trunk has about 54% TBSA (each leg 18%, front trunk 18%), illustrating how the rule translates injury extent into a usable number for treatment decisions.