A 28-year-old woman sustains a thermal burn covering 45% of her total body surface area (TBSA). The burn involves her entire anterior trunk, bilateral upper extremities, and the anterior aspect of the right lower extremity. Using the Rule of Nines for adult burn surface area calculation, which of the following is the MOST accurate assessment of the affected areas?

Explanation

## Rule of Nines for Adult Burn Surface Area **Standard Distribution (Adult):** | Body Area | % TBSA | |-----------|--------| | Head & Neck | 9% | | Anterior Trunk | 18% | | Posterior Trunk | 18% | | Bilateral Upper Extremities (each 9%) | 18% | | Bilateral Lower Extremities (each 18%) | 36% | | Perineum/Genitalia | 1% | | **Total** | **100%** | **Calculation for This Patient:** - **Anterior trunk:** 18% (entire anterior trunk) - **Bilateral upper extremities:** 9% + 9% = 18% (both arms completely involved) - **Right anterior lower extremity:** Each lower extremity = 18% total; anterior aspect = 50% of one limb = 9% ÷ 2 = 4.5% **Total TBSA = 18% + 18% + 4.5% = 40.5%** **Key Point:** The Rule of Nines divides each lower extremity into 18% TBSA. The anterior aspect of one lower extremity is approximately **half of one limb = 9%**, and the anterior aspect alone is **4.5%**. **High-Yield:** This is a **moderate burn** (40.5% TBSA) requiring fluid resuscitation and likely transfer to a burn center. The Parkland formula would apply: 4 mL × body weight (kg) × %TBSA = mL of Ringer's lactate over 24 hours.