A 32-year-old man sustains a thermal burn to his entire right upper limb and anterior trunk. Which feature best distinguishes the Rule of Nines estimation of total body surface area (TBSA) from the Lund and Browder chart in this clinical scenario?

Explanation

## Distinguishing Features of BSA Estimation Methods ### Rule of Nines **Key Point:** A rapid, field-friendly method that divides the body into multiples of 9%. - Head and neck: 9% - Each upper limb: 9% (anterior and posterior combined) - Each lower limb: 18% (anterior and posterior combined) - Anterior trunk: 18% - Posterior trunk: 18% - Perineum: 1% ### Lund and Browder Chart **Key Point:** A more precise, age-adjusted method that accounts for proportional differences in children. - Divides the body into smaller anatomical zones (head, neck, trunk, upper limbs, lower limbs, perineum) - Provides age-specific percentages (0–1 year, 1–4 years, 5–9 years, 10–15 years, adult) - Head percentage decreases with age (19% at birth → 7% in adults) - Lower limb percentage increases with age (14% at birth → 18% in adults) ### Comparison Table | Feature | Rule of Nines | Lund and Browder | |---------|---------------|------------------| | Speed of estimation | Very rapid (field use) | Slower (requires chart) | | Accuracy in adults | Good | Excellent | | Accuracy in children | Poor | Excellent (age-adjusted) | | Head allocation | Fixed 9% | Age-dependent (19% → 7%) | | Limb allocation | Fixed 9% per upper, 18% per lower | Age-dependent | | Trunk segmentation | Anterior/posterior only | Divided into smaller zones | | Clinical use | Initial triage, transport | Definitive assessment, fluid resuscitation | **High-Yield:** The **critical discriminator** is that Lund and Browder adjusts for age-related body proportions, whereas Rule of Nines uses fixed percentages regardless of age. This is why Lund and Browder is the gold standard for burn centres and fluid resuscitation calculations. **Clinical Pearl:** In a 32-year-old (adult), both methods are reasonably accurate, but Lund and Browder remains superior. In children, Rule of Nines significantly overestimates head TBSA and underestimates limb TBSA, making Lund and Browder mandatory. [cite:Park 26e Ch 10]