The rule-of-nines is a quick method to assess the extent of burn injury in an adult. To calculate the extent of the burn count:

1. 9% for both the anterior and posterior surfaces of the head and neck

2. 9% for both the anterior and posterior surfaces of each upper limb (18% for both)

3. 18% anterior trunk; 18% posterior trunk; 36% for both anterior and posterior trunk.

4. 9% for anterior, 9% for posterior surface of each limb (36% total for both lower limbs)

5. 1% for perineum