Integumentary System: Utilizing the Rule of Nines w/ Burns

The rule of nines is simply the classification of how bud a client has been burned regarding the body’s surface area. Aside from determining how far the burn has overwhelmed the client’s body, the rule of nines is also helpful in guiding healthcare professionals in their treatment plans.

In the medical field, the surface of the body is equivalent to 100%, and for very specific parts of the body, nine (9) is given. The more area that’s affected, the higher the percentage gets in terms of assessing how severe the client has been burned.

Hospital Scenario

The usual scenario with burn clients is someone will come into the Emergency Room with a scalding burn somewhere on the body or parents rushing their kids who were at the receiving end of a spilled teapot, all of which are by accident. So, the question is, how is the rule of 9s used in situations like this?

The Rule of Nines

The rule of nines was created to methodically and efficiently compute the extent of the affected area and to provide the needed care and treatment effectively. The rule of nines is a distribution of multiples of 9s for different parts of the body. That said, here are the percentages for each body part:

  • Thoracic cavity (anteriorly) – 18%
  • Thoracic cavity (posteriorly) – 18%
  • Legs with feet – 18% each
  • Arms – 9% each
  • Head with neck – 9%
  • Genitalia – 1%

Method Application

Now that you are aware of how every part of the body is determined, the next thing that you have to know is how the rule of nines is applied in a clinical setting. Here are examples of burned areas:

  • A burned upper portion of the arm = 4.5%
  • A circumferential burn that goes around the arm – 4.5% + 4.5% = 9%
  • A circumferential burn of the right leg = 18%
  • A circumferential burn of the entire thoracic cavity (front and back) = 36%
  • A burned area at the back of the head = 4.5%

Assessing a Third-Degree Burn

Here’s a hospital scenario for you:

A client comes in having circumferential burns on the body. Someone doused lighter fluid on the client and set him on fire. The client was determined to have full-thickness, third-degree burn with severe, deep eschar around the head, the thorax, and an entire arm and leg.

Using the rule of nines, how would the nurse provide an efficient assessment of the burned area?


Since the client has circumferential burns, using the rule of nines, here’s how he should be assessed:

  • Head – 9%
  • Thorax – 36%
  • An arm – 9%
  • A leg – 9%

To sum it up: 9 + 36 + 9 + 9 = 63%.

Therefore, the nurse in charge would indicate in the client’s chart that he suffered from a third-degree burn with 63% of his total body that’s affected.


Whenever you are staging a burn client, don’t forget that circumferential burns are doubled for the rule of nines. Also, the staging for adults is a bit different with babies. It is necessary to provide an accurate assessment regarding the extent of the burn to appropriately manage the client.

We have another lecture for the stages of burn, you can check that out and other nursing-related topics at Simple Nursing’s website and YouTube channel.