Body surface area

• Estimated with the "rule of 9's" for adults, where each major body group corresponds to 9% BSA
  • Entire head and neck (9%)
    • Face (3.5%)
    • Back of head (3.5%)
    • Front and back of neck (1% each)
  • Entire chest and abdomen (18%)
    • Chest (13%)
    • Abdomen and pelvis (5%)
  • Entire back and buttocks (18%)
    • Back (13%)
    • Buttocks (5%), with 2.5% per buttock
  • One entire arm (9%)
    • Front and back of upper arm (2% each)
    • Front and back of forearm (1.5% each)
    • Front and back of hand (1.25% each)
  • One entire leg (9%)
    • Front and back of thigh (4.75% each)
    • Front and back of leg (3.5% each)
    • Top and bottom of foot (1.75% each)
  • Genitals (1%)

	Birth to 1 Year	1 to 4 Years	5 to 9 Years	10 to 14 Years	15 Years	Adult
Head	19%	17%	13%	11%	9%	7%
Thigh	5.5%	6.5%	8%	8.5%	9%	9.5%
Leg	5%	5%	5.5%	6%	6.5%	7%