Impact Event — Collision or Fall Onset
Every trauma reconstruction starts with one moving body meeting one fixed surface.
- 0–120: Vehicle impact speeds (km/h modeled range)
- 0–30: Fall heights (meters modeled range)
- 40–120: Body mass range (kilograms modeled)
- <200: Contact duration (milliseconds typical)
Two impact archetypes
Vehicle collisions and falls differ, but both deliver sudden energy.
Why speed and height matter
Both variables set the velocity at the moment of contact.
Doubling speed quadruples kinetic energy, not doubles it.
Kinetic Energy Calculated From Mass and Motion
Energy at impact is computed directly from mass and either speed or fall height.
- ½mv²: Vehicle formula (mass × velocity squared)
- mgh: Fall formula (mass × gravity × height)
- 9.81: Gravity constant (m/s² used in model)
- Joules: Energy unit (standard SI energy unit)
Kinetic energy formula
½mv² converts vehicle speed and body mass into joules.
Potential energy formula
mgh converts fall height into the same joule scale.
Both formulas feed one shared severity model.
Energy Transfer Into Tissue and Bone
At contact, kinetic energy transfers into the body at the point of impact.
- <50: Transfer window (ms for rigid contact)
- Contact: Peak force zone (point concentrates load)
- High-g: Deceleration (sudden velocity change)
- Deform: Tissue response (then rebound or fail)
Contact point loading
Energy concentrates wherever the body first meets the surface.
Deceleration and injury
Faster stopping means more force delivered per second.
Shorter stopping distance always raises peak force.
Injury Severity Correlation With Impact Energy
Higher calculated impact energy correlates with more severe injury patterns.
- <400 J: Minor threshold (bruising, soft tissue)
- 1.2–3 kJ: Severe threshold (fracture likely)
- 3–6 kJ: Critical threshold (multi-system trauma)
- >6 kJ: Fatal threshold (non-survivable range)
Severity bands
Energy is grouped into five escalating injury bands.
Not a hard cutoff
Bands are statistical tendencies, not certainties.
Real cases vary with anatomy and impact angle.
Forensic Injury Estimate From Impact Energy
A likely injury severity and survivability estimate closes the reconstruction.
- 5: Output classes (minor through fatal)
- Exponential: Survivability model (decays with energy)
- Forensic: Use case (trauma reconstruction)
- Estimate: Confidence (not a diagnosis)
Reading the estimate
Severity and survivability are read straight off the gauge.
Limits of the model
This is an educational estimate, not a medical finding.
Always defer to actual clinical or forensic exam.