Biomechanics and Injury Analysis

    Biomechanical and injury analysis can be used to determine what forces, torques, and kinematics were involved in causing a specific injury. Dr. Fijan does not diagnose medical injuries; rather, he analyses the forces, torques, and kinematics that were generated during the accident and compares these with the diagnoses made by medical personnel.  

    Dr. Fijan analzses medical data, information from vehicle and accident site inspections, data from vehicle-to-vehicle crash tests (including dynamic data from anthropomorphic test dummies in vehicle sled tests), and computer modeling to evaluate kinematics, contacts, and injuries during an accident.


    Dr. Fijan has considerable expertise in evaluating motor vehicle accidents, occupant kinematics, injury mechanics, and human injury tolerance. Dr. Fijan has conducted hundreds of biomechanical analyses in accidents ranging from single and multi-vehicle collisions, including passenger cars, light and heavy trucks (including SUVs and vans), bicycles and motorcycles


    Things that can be determined 

    • How did an occupant move around inside the vehicle during an accident?
    • What forces or joint motions did an occupant experience during the accident?
    • Does the testimony of how an occupant moved around make sense?
    • How large are the accident forces compared to injury tolerance thresholds or forces associated with everyday activities?
    • Which, if any, of an occupant’s claimed injuries could have been sustained during a specific motor vehicle accident?
    • Based on injuries and other evidence (e.g. windshield fracture), where was an occupant most likely positioned within the vehicle?
    • Was an occupant properly wearing the available seatbelt restraint?
    • If an improperly restrained occupant had been properly wearing the available seatbelt restraint, then what injuries may have resulted?
    • Did the injuries occur inside or outside of the vehicle (when ejection occurs)?
    • In a multi-impact accident, during which event did an occupant sustain a specific documented injury? 

    These and other questions can be addressed using rigorous biomechanical analyses.  Based on results from accident reconstruction analyses, and incorporating occupant-specific geometry and inertia data, the motions and forces an occupant experiences can be analyzed.  Joint ranges of motion and impact forces may be estimated and compared with injury tolerance thresholds documented in the biomechanics literature, and also compared to joint motions and forces associated with benign everyday activities.  An accident can be analyzed to determine if it included a mechanism for a specific occupant’s injury. 

    For some occupant seating positions in some motor vehicle accidents, seat belts may play a major mitigating role for certain injuries.  Biomechanical analyses may assess the likelihood of a sustained injury having occurred if an occupant had been properly restrained, or conversely to determine if an occupant was likely wearing the restraint during the accident based on injuries, ejection from the vehicle, etc. 

    Relevant biomechanical and seat belt analyses are performed based on: 

    • estimated, known or assumed vehicle motions (accident reconstruction)
    • occupant seating positions
    • occupant height and weight
    • vehicle-specific interior geometry and structural stiffness
    • available seatbelt, airbag or other restraints
    • vehicle interior “witness marks”
    • documented occupant injuries
    • pedestrian or ejected occupant rest or impact positions
    • lists of activities an occupant participated in prior to an accident (for comparison purposes)