Rule of Nines
Last reviewed 01/2018
Wallace's Rule of Nines provides a quick, approximation of the area of skin burnt. Arbitrarily, it divides the body up into units of surface area divisible by nine - with the exception of the perineum. Usually, charts of area are available in most burns units.
In an adult, the following are the respective percentages of the total body surface area:
- head and neck total for front and back: 9%
- each upper limb total for front and back: 9%
- thorax and abdomen front: 18%
- thorax and abdomen back: 18%
- perineum: 1%
- each lower limb total for front and back: 18%
The Rule of Nines is relatively accurate for adults but not for children due to the relative disproportion of body part surface area - see submenu.