The rule of nines is a great tool for quickly estimating the percentage of burn injury present on a patient. It’s an important assessment skill that will be used during your career and will likely come up during the National Registry of EMT Cognitive Exam. All EMTs and paramedics should have a clear understanding of the body percentages listed on the rule of nines chart below.
What is the Rule of Nines
The rule of 9s is a tool used by medical personnel to quickly estimate the size and severity of a burn injury. The rule of nines is often used in the prehospital setting by EMTs and paramedics. It divides the body into segments that are mostly multiples of nine to help medical workers determine the total body surface area (TBSA) that’s been burned.
When to Use the Rule of Nines
The rule of 9s is used to estimate the surface area of injuries that are second degree burns or greater. Any medical personnel can use the rule of nines, but it’s especially useful for EMS in prehospital settings. EMTs are likely to be tested on the rules of nines during the NREMT cognitive exam.
Use on second degree burns or greater.
Rule of Nines: Burns
The rule of 9s for an adult divides the body into segments that are mostly multiples of nine. For example, an entire arm is considered 9%, the stomach is 9%, the chest is 9%, and the entire head is 9%. However, the Rule of Nines: Adult image below divides the body into anterior and posterior sections, which is a common technique for memorization.
All this information can be hard to keep memorized. You can find a useful badge sized card with both the rule of nines and the rule of palms details on it by clicking here.
Infant Rule of Nines
Infants have a larger head and different proportions than an adult. Therefore, their percentages are slightly different than an adults when using the rule of 9s. Here is a graphic for the rule of nines for an infant one year old or less.
Remember that everyone has a front and back so you should also know how the numbers relate to the posterior and anterior of the patient.
For example, the ENTIRE infant head is labeled as 18% so the front of the head is 9% and the back of the head is 9%. This can trip people up when taking the NREMT exam.
Rule of Nines Chart
Below are an infant and adult rule of nines chart. It has the same information as the images above, but it’s listed in a different format for clarity.
Adult Rule of Nines Chart
Infant Rule of Nines Chart
If you are looking for a great field resource that contains rule of nines information along with many other resources for both EMTs and AEMTs, checkout the BLS Pocket EMS Field Guide.
Function of the Rule of 9s
- Helps speed up assessment and quickly determine an estimate of burn injury surface area, also know as TBSA (total body surface area).
- Helps determine the severity of burns.
- Indicates whether the patient must be transported to a burn unit.
- Used to decide if the patient is a candidate for fluid replacement therapy.
- Can be used to calculate the amount of fluids the patient will be given over the next 24 hours.
Care should never be delayed so you can estimate a percentage of the body that is burned.
Rule of Palms
On some occasions, burns will be small, irregular or scattered throughout the body in random patterns. This makes it difficult to estimate TBSA using the rule of 9s.
Use the patient’s palm size and not your own hand size.
In these cases, you can use the patient’s palm size, including fingers, to represent 1% of TBSA and use this to estimate the amount of burn injury.
There is some confusion and a lot of conflicting information on websites about what is meant by the term “palm”. According to all the research and the American Burn Association (page e428).
“The size of the patient’s palm should include the fingers in order to represent approximately 1% of the total body surface area.”
Research shows that the palm without fingers included tends to be about 0.5% of TBSA. Here are a couple articles about palm size, there are more available with a simple internet search.
Overestimating the amount of burn injury has led to over hydration of burn patients, so it’s important to use the correct palm size when using the rule of palms.
Check out our other EMS posts:
→ Our Guide for Auscultating Lung Sounds
→ Recognizing Carbon Monoxide Poisoning
→ 35 Great Books for EMTs and Paramedics
Christina Beutler is the creator of EMT Training Base. She is a former EMT and a current Registered Nurse. Christina’s path changed after taking a Basic First Aid class while in Community College, and a career in healthcare opened up. Working as an Emergency Medical Technician led to a passion for nursing and a job working in the Intensive Care Unit and Critical Care Unit right out of Nursing School. To learn more about Christina’s story, head over to the About page.
