Rule of Nines for Burns: Child & Adult Chart Calculations
The Rule of Nines (9s) for burns in a child, infant, and adult. Includes charts, calculations, definitions, formulas, and example practice questions! Great for EMTs, pediatrics, nursing, and more!
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Rule of Nines for Burns
Many healthcare professionals will encounter at least one burn patient throughout their career.
Therefore, it is important to know how to appropriately assess and manage a patient with burns, especially when burns can vary in size and severity.
The Rule of Nines can be used as part of the initial burn assessment to help guide care.
In this post we will use charts, tables, and diagrams to clearly outline the Rule of Nines, what it is, and how it works.
There are example practice questions and scenarios at the end of this post, so make sure to try them out and quiz yourself to see if you are right!
Without further ado, let’s get right into it!
Rule of Nines - Definition
The Rule of Nines can be used in burn patients to estimate the total body surface area affected by partial thickness (2nd-degree) and full thickness (3rd-degree) burns.
Knowing the total body surface area (TBSA) involved will help guide the patient’s care, provide an estimate for fluid resuscitation, and determine if the patient requires care at a specialized burn center.
The Rule of Nines is for partial thickness and full thickness burns, which are second-degree and third-degree burns respectively.
Superficial (first-degree) burns are not included in the calculation.
Let’s walk through the table and diagram below, and you will quickly see why it is called the Rule of Nines and how it is used.
Rule of Nines for Burns: Used as part of the burn assessment to estimate the TBSA involved.
Rule of Nines - Chart
The Rule of Nines provides an estimated body surface area (BSA) percentage for different body parts.
The Rule of Nines is typically used in non-obese adults, as it can be inaccurate in pediatric and obese patients - more on that below!
Let’s review the Rule of Nines using the table below as a reference!
Rule of Nines - Calculations
The Rule of Nines dictates a TBSA of 9% for the entire head and neck.
The entire right arm and left arm each have a TBSA of 9%.
The entire trunk has a TBSA of 36%.
The groin/perineum has a TBSA of 1%,
Finally, the entire right leg and left leg each have a TBSA of 18%.
This totals 100%.
With the exception of the groin, you can see how the percentages are multiples of 9 which is how the rule gets its name.
Rule of Nines Chart: The rule of nines provides a body surface area percentage for different parts of the body.
Trick to Remember the Percentages
The BSA percentages increase in alphabetical order.
“A” and “H” = Arms and Head = 9%
“L” = Legs = 18%
“T” = Trunk = 36%
First, the “A” and “H” for “Arms” and “Head” each have a TBSA of 9%.
Next, the “L” for “Legs” has a higher TBSA of 18%.
Finally, the “T” for “Trunk” has an even higher TBSA of 36%.
The groin is not included in this trick, but is easy to remember at 1%.
Once you have committed the percentages to memory, then the rest becomes easy.
Rule of Nines - Diagram
The table above shows the TBSA percentages for entire body parts.
We can divide the percentages in half and apply them to the anterior (front) and posterior (back) aspects of the body.
Use the diagram below as a reference!
We know the TBSA of the entire head and neck is 9%. Therefore, the face and anterior neck make up 4.5%, and the posterior head and neck make up 4.5%.
The entire right arm has a TBSA of 9%. Therefore, the anterior right arm is 4.5%, and the posterior right arm is 4.5%.
The left arm is the same where the anterior and posterior sides are each 4.5%.
The entire trunk has a TBSA of 36%. Therefore, the anterior trunk is 18%, and the posterior trunk is 18%.
The anterior trunk can be broken down further where the chest is 9% and the abdomen is 9%.
The perineum has a TBSA of 1%.
The entire right leg has a TBSA of 18%. Therefore, the anterior side is 9%, and the posterior side is 9%.
The left leg is the same where the anterior and posterior sides are each 9%.
Rule of Nines Burn Chart and Diagram: Body surface area percentages for different parts of the body.
Rule of Nines in a Child
The Rule of Nines is typically used in non-obese adults, as it can be inaccurate in pediatric and obese patient populations.
Pediatric patients have disproportionately larger heads and shorter legs.
As a result, the BSA percentages in children will differ from adults.
For example, an infant head is disproportionately larger with a TBSA of approximately 21% instead of 9%.
Each arm has a TBSA of about 10%, the entire trunk is about 26%, the buttocks and groin are about 6%, and each leg is about 13.5%.
Of note, the table and diagram below are approximate percentages for infants and young children.
These percentages can vary and will change in older pediatric patients.
The Lund and Browder chart can also be used to assess TBSA in infants and children.
Rule of Nines in a Child: Burn assessment chart for a pediatric baby, infant, or young child.
Rule of Nines in an Obese Adult
As mentioned above, the other patient population in which the Rule of Nines can be inaccurate is obese patients.
Patients that are defined as obese based on their BMI have disproportionately larger trunks, and the Rule of Nines is typically inaccurate.
The TBSA of the trunk in obese patients can be closer to 50% compared to their non-obese counterparts who have a trunk size of 36%.
Due to their disproportionate trunk size, the other BSA percentages are slightly different in obese patients as shown in the table and diagram below.
The TBSA of the entire head and neck is 6%, each arm is 7%, the groin is 1%, and each leg is 15%.
The percentages are approximations as they can vary among obese patients.
Rule of Nines Burn Chart for an Obese Adult vs Non-Obese Adult
Things to Know…
There are a few things to know about the Rule of Nines.
First, the Rule of Nines is for partial thickness and full thickness burns.
Superficial burns are not included in the TBSA calculation.
Although the Rule of Nines is an efficient easy-to-remember method for calculating the TBSA involved, it can often lead to overestimations.
Next, the patient’s palm (excluding digits) is approximately 0.5% TBSA, and their entire hand (including digits) is about 0.8-1% TBSA.
So for smaller burns, the size of the patient’s own hand (not yours) can be used to approximate the area involved.
Some literature states the patient’s palm (excluding digits) is 1% TBSA, however recent studies have shown this to potentially be an overestimation.
Lastly, burn patients can have fluid losses from capillary leak and damage to the skin (loss of the skin barrier).
Therefore, calculating the TBSA involved is important in estimating fluid resuscitation, along with the patient’s overall care and potential need for treatment at a designated burn center.
Equations such as the Parkland formula can be used to calculate how much fluid resuscitation the patient requires after determining their TBSA involved.
Rule of Nines: High-yield information about using the rule of nines for burn assessment.
Rule of Nines - Practice Question # 1
Let’s review a couple examples.
Try to figure out the TBSA involved for each burn scenario.
The first patient has partial thickness burns involving the entire anterior chest and the entire anterior right arm.
What is the TBSA?
Answer
Anterior Chest = 9%
Anterior Right Arm = 4.5%
TBSA = 13.5%
Rule of Nines for Burns: Example and Practice Question # 1
Explanation
Since the burns are partial thickness burns, they are included in the TBSA calculation.
Remember superficial burns are not included in the rule of nines.
We know the entire trunk has a TBSA of 36%, and just the anterior trunk has a BSA of 18%.
Since this burn only involves half of the anterior trunk (chest but not abdomen), then the burn to the anterior chest has a TBSA of 9%.
There is also a burn involving the entire anterior right arm.
We know the entire right arm has a TBSA of 9%.
Since this burn only involves the anterior aspect, then it has a TBSA of 4.5%.
So this patient with partial thickness burns to the anterior chest and anterior right arm involves a TBSA of 13.5% (9% + 4.5% = 13.5%).
Rule of Nines - Practice Question # 2
Let’s look at one more example.
This patient has a full thickness burn to the distal anterior left arm and a partial thickness burn to the proximal anterior left leg.
What is the TBSA?
Answer
Distal Anterior Left Arm = ~2%
Proximal Anterior Left Leg = 4.5%
TBSA = ~6.5%
Rule of Nines for Burns: Example and Practice Question # 2
Explanation
Since the burns are partial thickness and full thickness burns, they are included in the TBSA calculation.
We know the entire left arm has a TBSA of 9%, and just the anterior side is 4.5%.
Since this burn only involves half of the anterior aspect (distal half), then the BSA would be approximately 2%.
There is also a burn to the proximal anterior left leg.
We know the entire left leg has a TBSA of 18%, with the anterior aspect totaling 9%.
Since this burn involves half of the anterior aspect (proximal half), then the BSA would be approximately 4.5%.
So this patient’s burns involve a TBSA of about 6.5% (~2% + 4.5% = ~6.5%).
Rule of Nines - Quiz Yourself!
Now it is your turn!
Try to fill in the table and diagram using the rule of nines.
You can do this for a non-obese adult, pediatric patient, or an obese adult.
Use the tables and diagrams above to check your answers.
Rule of Nines Quiz: Fill in the burn chart and diagram for an adult, a child, and an obese adult. Check your answers above!
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Referenceshttps://www.ncbi.nlm.nih.gov/books/NBK513287/https://www.mottchildren.org/health-library/sig254759https://www.health.state.mn.us/communities/ep/surge/burn/tbsa.htmlhttps://www.cigna.com/individuals-families/health-wellness/hw/rule-of-nines-for-burns-in-babies-and-young-aa41815https://myhealth.alberta.ca/Health/Pages/conditions.aspx?hwid=aa41815