Biomechanics

Biomechanical engineering bridges the fields of medicine and mechanical engineering. It is the study of the mechanics of living beings. Biomechanical engineers (sometimes called biomechanists) have a knowledge of physics and anatomy and are particularly concerned with the forces exerted on the body's structures and the effects of these forces (e.g., motion, stresses and strains).

While medicine focuses primarily on diagnosis and treatment of injuries, biomechanical engineers analyze the conditions in which injuries are sustained by examining human body movement, loading and tolerances. Similarly, although mechanical engineers are well versed in the concepts of dynamic forces and loading, they do not usually have an understanding of human injury tolerance. Biomechanical engineers, through their understanding of forces and the impact of forces on the human body, can provide insight into the injury mechanics of the incident under examination.

The two main questions are asked of a biomechanical engineer:

Did the incident in question cause the reported injury?
Could the injury have been prevented?

A biomechanical assessment focuses on the mechanism and magnitude of the impact forces that were present. More specifically, did a mechanism exist to produce the reported injury and if it did, was there sufficient magnitude to produce the reported symptoms?

For biomechanists, relevant topics in the civil litigation of injury accidents include the following:

  1. Occupant Dynamics and Kinematics
  2. Injury Potential Determination
  3. Injury Mechanisms
  4. Restrained/Unrestrained Occupant Injury Comparisons
  5. Ejected Occupants
  6. Safety Helmet Assessments
  7. Slip, Trip and Fall Investigations
  8. Low speed impact analysis
  9. Identification of occupant seating positions

Occupant Motion and Injuries

A biomechanical evaluation and a review of available medical documentation are used to evaluate occupant motion during a motor vehicle collision and to predict expected injuries. This can then be used to determine whether the given collision is likely to have caused the reported injuries, and if the presence of pre-existing medical conditions contributed to the injuries that were sustained.


Restrained/Unrestrained Occupant Injury Comparisons

Once seat belt usage has been established by an accident reconstruction, a biomechanical assessment can provide a more detailed analysis of the extent of benefit that the occupants of the various vehicles would have received at the time of collision by wearing their seat belts. For example, if the occupants were not belted, which of their injuries could have been prevented by the proper use of a seatbelt?


Safety Helmet Assessments

When injuries are sustained by an individual wearing a safety helmet, a biomechanical engineer can examine the helmet to determine whether it complies with current safety standards and whether it was the proper type of helmet for the purpose for which it was used.


Slip, Trip & Fall

When there is a need to closely examine the injuries sustained by a person who has slipped, tripped or fallen, a biomechanical investigation may be necessary. A biomechanical evaluation of the incident and a detailed review of the relevant medical documentation can assess a range of issues: the presence of pre-existing medical conditions that contributed to the injuries; a comparison of expected and reported injuries; a comparison of likely injuries from multiple possible incident scenarios to elucidate discrepancies in statements about how the incident occurred; a comparison of differences in injury outcome from a fall on a surface (or from a structure) that does not comply to code, to a fall on one that does.


Low Speed Impact Analysis

Even after a typical low speed accident reconstruction has been completed, some incidents require further analysis of the occupants' injuries. For example, did the presence of pre-existing medical conditions contribute to the injuries sustained? Is it unlikely that an occupant would have sustained the injuries reported in an impact of this severity?

Sintra Engineering has published a research paper through the Society of Automotive Engineers SAE) that developed injury symptom risk curves for low speed collisions. We are currently conducting additional research that addresses the expected duration of symptoms experienced by individuals involved in a low speed collision.


Identification of the Occupant Seating Positions

It can be important to know where the individuals involved in a motor vehicle collision were seated. For example, it is often critical to know who was driving, even though that information may not be clear from the superficial physical evidence present immediately following the collision. By examining the vehicle and its interior, and considering the details of the injuries sustained by the occupants, a biomechanical engineer can determine the location of the occupants in the vehicle at the time of the incident.