Wallace rule of nines

The Wallace rule of nines is a tool used in pre-hospital and emergency medicine to estimate the total body surface area (BSA) affected by a burn.

[1] The rule of nines was devised by Pulaski and Tennison in 1947, and published by Alexander Burns Wallace in 1951.

Thus, if a patient's entire back (18%), but only half of their left leg (9%) was burned, the amount of BSA affected would be 27%.

[1] One study found the rule's accuracy to be "reasonable" for patients weighing up to 80 kg, but proposed a new "rule of fives" for patients over that weight:[1] Other studies have found that the rule of nines tends to over-estimate total burn area,[5] and that ratings can be subjective,[6] but that it can be performed quickly and easily, and provide reasonable estimates for initial management of burn patients.

The remainder of the body parts retain the same BSA percentages used in the adult rule of nines.

Burn severity is determined through, among other things, the size of the skin affected. The image shows the makeup of different body parts, to help assess burn size.