Total body surface area (TBSA) is an assessment measure of burns of the skin. In adults, the "rule of nines" is used to determine the total percentage of area burned for each major section of the body. In some cases, the burns may cover more than one body part, or may not fully cover such a part; in these cases, burns are measured by using the casualty's palm as a reference point for 1% of the body.
For children and infants, the Lund-Browder chart is used to assess the burned body surface area. Different percentages are used because the ratio of the combined surface area of the head and neck to the surface area of the limbs is typically larger in children than that of an adult.
Typical values for common groups of humans follow. (Due to rounding, values may not add to 100%.)