Burns
Background Information
Classification of Burn Depth
| Depth of burn | Affected skin | Skin appearance | Blisters | Sensation | Capillary refill |
|---|---|---|---|---|---|
| Superficial epidermal | Epidermis (no dermis involvement) | Red | No | Painful (normal) | Blanches then refill rapidly |
| Superficial dermal | Epidermis + superficial dermis (no deep dermis involvement) | Red / pale pink (moist) | Yes | Blanches then refill slowly | |
| Deep dermal | Epidermis + entire dermis (no subcutaneous involvement) | Blotchy / mottled / red (dry) | Painful (less intense) | Does not blanch | |
| Full thickness | Epidermis + dermis + subcutaneous tissue +/- muscle and bone | White / brown / black (charred)
Dry / leathery / waxy |
No | Painless |
One may still come across the traditional burn classification system in some textbooks, clinical notes, or older resources. This is how the latest classification (shown above) corresponds to the old classification:
- Superficial epidermal = old 1st degree burn
- Superficial dermal + deep dermal = old 2nd degree burn
- Full thickness = old 3rd degree burn
Classification of Burn Extent
There are 3 main ways to estimate the burn extent, measured by TBSA – the % of the body suface area that is burnt / affected.
Wallace’s Rule of 9s
The rule of 9s estimates the body surface area using multiples of 9, representing different areas of the body:
- Head + neck = 9%
- Each upper limb = 9%
- Anterior torso = 18%
- Posterior torso = 18%
- Each lower limb = 18%
- Perineum and genitalia = 1%
It is possible for exam questions to ask one to estimate the TBSA by providing a written description of what parts of the body are affected / burn (e.g. this patient comes in with his entire left arm and leg burnt, what is the estimated burnt surface area?). Therefore, students are recommended to memorise the rule of 9s by heart.
Rule of Palm
The rule of palm is a simple method to estimate the TBSA by using the patient’s palm as a reference:
dsfsfsf
- The entire palmar surface of the patient’s hand (including the fingers) represents ~1% of body surface area
The rule of palm is mainly useful for irregular burn patterns or small burnt areas.
Lund and Browder Chart
The Lund and Browder chart is the gold standard and most accurate method to estimate TBSA across all age groups (adults, children and babies)
- The chart divides the body into multiple regions, each assigned a specific percentage that represents its contribution to body surface area
- It accounts for changes in body proportions with age, especially important in children (e.g., a larger head relative to body).