Injury Severity Score - Determining The Seriousness Of Injuries
The Injury Severity Score (ISS) is an anatomical scoring system that provides an overall score for patients with multiple injuries.
Each injury is assigned an Abbreviated Injury Scale (AIS) score, allocated to one of six body regions:
- head
- face
- chest
- abdomen
- extremities (including pelvis)
- external
Only the highest AIS score in each body region is used.
The three most severely injured body regions have their score squared and added together to produce the ISS score.
COPYRIGHT_SPINE: Published on https://spinal-injury.net/injury-severity-score/ by Dr. Bill Butcher on 2022-10-24T11:17:32.075Z

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ISS Calculator
The ISS Calculator can be found online. One just simply needs to input the right details and the computation will be performed online on someone’s behalf.
The parts of the body under the “Abbreviated Injury Scale” include the Head, Face, Chest, Abdomen, Extremities, and External.
In her article published by MDCalc.com, Dr. Susan Baker, an epidemiologist at Johns Hopkins Bloomberg School of Public Health who specializes in injury prevention, identified seven descriptions for a specific injury.
For example, the question is: “Head and neck worst injury?” The following are the answers (as mentioned by Dr. Baker) to arrive at an Injury Severity Score:
- No injury
- Minor
- Moderate
- Serious
- Severe
- Critical
- Unsurvivable
ISS Calculation
A sample calculation for an Injury Severity Score is shown below:
1. First example
a. Region - head and neck
b. Injury Description - cerebral contusion
c. Abbreviated Injury Scale (AIS) - 3
d. Square Top Three - 9
2. Second example
a. Region - face
b. Injury Description - no injury
c. AIS - 0
d. Square Top Three - none
3. Third example
a. Region - chest
b. Injury Description - flail chest
c. AIS - 4
d. Square Top Three - 16
4. Fourth example
a. Region - abdomen
b. First Injury Description - minor contusion of liver
c. AIS - 2
d. Second Injury Description - complex rupture spleen
e. AIS - 5
f. Square Top Three - 25
5. Fifth example
a. Region - extremity
b. Injury Description - fractured femur
c. AIS - 3
d. Square Top Three - none
6. Sixth example
a. Region - external
b. Injury Description - no injury
c. AIS - 0
d. Square Top Three - (blank)
Add all the scores under “Square Top Three” and the Injury Severity Score is 50.