Estimating Burn Size: Rule of Nines, Palms, and Lund-Browder Practice Questions

25 multiple-choice questions on Estimating burn size: rule of nines, palms, and Lund-Browder for paramedic and EMT students, from Chapter 33 (Burns). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. In the adult rule of nines, the entire head and neck account for:

   1. A. 18%
   2. B. 4.5%
   3. C. 1%
   4. D. 9%
   Show answer

   Answer: D. 9%

   The adult head is 9%. In infants the head is about 18%, which is the figure students often confuse with the adult value.

2. In the adult rule of nines, each entire upper extremity accounts for:

   1. A. 18%
   2. B. 4.5%
   3. C. 9%
   4. D. 14%
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   Answer: C. 9%

   Each arm is 9%, front and back together. 4.5% is only the front or back of one arm.

3. In the adult rule of nines, each entire lower extremity accounts for:

   1. A. 9%
   2. B. 18%
   3. C. 14%
   4. D. 27%
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   Answer: B. 18%

   Each leg is 18%, or 9% for the front and 9% for the back. 14% is the approximate infant leg value.

4. In the adult rule of nines, the anterior trunk (chest and abdomen) accounts for:

   1. A. 9%
   2. B. 27%
   3. C. 18%
   4. D. 36%
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   Answer: C. 18%

   The front of the trunk is 18% and the back is another 18%. 9% is only the chest or only the abdomen.

5. In the adult rule of nines, the genitalia and perineum are assigned:

   1. A. 1%
   2. B. 9%
   3. C. 4.5%
   4. D. 0.5%
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   Answer: A. 1%

   The perineum completes the total of 100%. Although small, burns here still meet burn center referral criteria.

6. In the pediatric rule of nines for an infant, the head and neck account for about:

   1. A. 9%
   2. B. 14%
   3. C. 27%
   4. D. 18%
   Show answer

   Answer: D. 18%

   An infant's head is proportionally large, so it is about 18%. The 9% figure applies to adults.

7. In the pediatric rule of nines for an infant, each lower extremity accounts for about:

   1. A. 18%
   2. B. 9%
   3. C. 14%
   4. D. 21%
   Show answer

   Answer: C. 14%

   Infant legs are relatively small, about 13.5% to 14% each. The adult value of 18% would overestimate leg burns in a baby.

8. As a child grows older than 1 year, the proportion of body surface represented by the head:

   1. A. Increases while the legs decrease
   2. B. Stays fixed until adolescence
   3. C. Decreases along with the legs
   4. D. Decreases while the legs increase
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   Answer: D. Decreases while the legs increase

   Roughly 1% shifts from head to legs each year until adult proportions are reached around age 10 to 15. This is why age-specific charts are more accurate than one fixed rule.

9. The rule of palms states that the patient's palm, including the fingers, represents about:

   1. A. 5% of their TBSA
   2. B. 1% of their TBSA
   3. C. 9% of their TBSA
   4. D. 0.1% of their TBSA
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   Answer: B. 1% of their TBSA

   By ABA and ABLS convention the whole palmar surface, fingers included, is about 1% of TBSA (measured studies put it nearer 0.8% in adults, so the estimate runs slightly high); the palm without fingers is only about 0.5%. 5% and 9% overstate a hand many times over; 9% is the rule-of-nines value for an entire adult arm. 0.1% understates it tenfold.

10. The rule of palms is most useful for estimating:

    1. A. Small or scattered burns
    2. B. Burns of an entire limb
    3. C. Burns covering most of the body
    4. D. Superficial sunburns only
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    Answer: A. Small or scattered burns

    Patchy burns are hard to fit into the rule of nines, so they are measured in patient-palm units. For whole regions, the rule of nines is faster.

11. When using the rule of palms, the hand used for measurement should be:

    1. A. The paramedic's hand
    2. B. The patient's own hand
    3. C. An average adult's hand
    4. D. A standard 10 cm card
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    Answer: B. The patient's own hand

    Palm size scales with the patient's body size. Using a large rescuer's hand on a small child would underestimate the burn.

12. The Lund-Browder chart is more accurate than the rule of nines because it:

    1. A. Includes superficial burns in the total
    2. B. Uses the paramedic's palm as a guide
    3. C. Adjusts body part values for age
    4. D. Measures burn depth instead of size
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    Answer: C. Adjusts body part values for age

    Lund-Browder assigns age-specific percentages to many small regions. It is the standard in burn centers, though the rule of nines is quicker in the field.

13. A 30-year-old man has partial-thickness burns of the entire front of both legs. His burned TBSA is about:

    1. A. 9%
    2. B. 36%
    3. C. 27%
    4. D. 18%
    Show answer

    Answer: D. 18%

    The front of each adult leg is 9%, so both fronts total 18%. 36% would be both entire legs, front and back.

14. A 45-year-old woman has a partial-thickness burn of her entire right arm and the entire front of her chest, but not her abdomen. Her burned TBSA is about:

    1. A. 18%
    2. B. 27%
    3. C. 13.5%
    4. D. 36%
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    Answer: A. 18%

    The arm is 9% and the chest is half of the 18% anterior trunk, or 9%. Counting the whole anterior trunk would give the 27% distractor.

15. A 25-year-old firefighter has partial-thickness burns of his entire back and the back of both legs. His burned TBSA is about:

    1. A. 27%
    2. B. 45%
    3. C. 36%
    4. D. 18%
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    Answer: C. 36%

    Posterior trunk is 18% plus 9% for the back of each leg, for 36%. Using 18% for each leg back would give 54%, and leaving one out gives 27%.

16. A 9-month-old pulled a pot of hot water onto herself, burning her entire head and the front of her chest and abdomen. Using the pediatric rule of nines, her TBSA is about:

    1. A. 27%
    2. B. 18%
    3. C. 45%
    4. D. 36%
    Show answer

    Answer: D. 36%

    Infant head is 18% and anterior trunk is 18%, for 36%. Using the adult 9% head value would give the 27% distractor.

17. A 40-year-old man has full-thickness burns of the entire front and back of his left leg and partial-thickness burns of the front of his left arm. His burned TBSA is about:

    1. A. 27%
    2. B. 22.5%
    3. C. 18%
    4. D. 13.5%
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    Answer: B. 22.5%

    The whole leg is 18% and the front of one arm is 4.5%, for 22.5%. Counting the whole arm would give 27%.

18. A 32-year-old woman has a red, unblistered sunburn over her back and partial-thickness scalds over her entire right arm. The TBSA used for burn calculations is:

    1. A. 9%
    2. B. 27%
    3. C. 18%
    4. D. 4.5%
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    Answer: A. 9%

    Only the partial-thickness arm burn counts, at 9%. Adding the superficial back burn would wrongly give 27%.

19. A 50-year-old man has scattered partial-thickness burns from a grease fire. You estimate the burned areas would be covered by about seven of his own palms. His TBSA is about:

    1. A. 14%
    2. B. 3.5%
    3. C. 63%
    4. D. 7%
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    Answer: D. 7%

    Each palm with fingers is about 1%. The 63% distractor wrongly treats each palm as 9%.

20. Field estimates of burn size are most often in error because providers:

    1. A. Underestimate the full-thickness areas
    2. B. Forget to count the hands and feet
    3. C. Count superficial burns and overestimate
    4. D. Measure with the patient's own palm
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    Answer: C. Count superficial burns and overestimate

    Studies show referring providers overestimate TBSA, largely by counting superficial redness. Overestimation leads to excess fluids and unnecessary transfers.

21. A 28-year-old man has circumferential partial-thickness burns of both entire arms and his entire head and neck. His burned TBSA is about:

    1. A. 18%
    2. B. 27%
    3. C. 36%
    4. D. 45%
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    Answer: B. 27%

    Each arm is 9% and the head is 9%, for 27%. Using the infant head value of 18% would give the 36% distractor.

22. In a patient with obesity, the rule of nines tends to be inaccurate because:

    1. A. The trunk is a larger share of TBSA
    2. B. The head makes up a larger share of TBSA
    3. C. Burns are always deeper in fat tissue
    4. D. Palms are relatively larger in obesity
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    Answer: A. The trunk is a larger share of TBSA

    In obesity the trunk is proportionally larger and the limbs and head smaller, so standard values misrepresent TBSA. Fat does not change the percentage rule for the head.

23. A 4-year-old has partial-thickness burns of both entire legs. Compared with the adult rule of nines estimate, the true TBSA in this child is:

    1. A. Higher, because a child's legs are larger
    2. B. Lower, because a child's legs are smaller
    3. C. Exactly the same at any age
    4. D. Impossible to estimate before age 10
    Show answer

    Answer: B. Lower, because a child's legs are smaller

    Children's legs make up a smaller share of body surface than adults', so the adult 36% would overestimate. A Lund-Browder chart or pediatric rule corrects for age.

24. A 60-year-old man has partial-thickness burns of his anterior trunk, his genitalia, and the front of both arms. His burned TBSA is about:

    1. A. 37%
    2. B. 19%
    3. C. 27%
    4. D. 28%
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    Answer: D. 28%

    Anterior trunk 18% plus perineum 1% plus 4.5% for each arm front, for 28%. Counting both entire arms gives 37%.

25. When you describe a burned patient to the receiving burn center, the most useful report includes:

    1. A. Partial- and full-thickness TBSA
    2. B. Total red area, including superficial
    3. C. Only the deepest single wound
    4. D. A guess of the depth by color only
    Show answer

    Answer: A. Partial- and full-thickness TBSA

    Burn centers use partial- and full-thickness TBSA to plan fluids and care. Including superficial redness makes the report less useful and inflates the estimate.