Mechanisms of Injury in Motor Vehicle Collisions
Mechanisms of injury refers to how traumatic forces affect the human body, causing injury.
How can LNCs help attorneys with motor vehicle crash cases? You will need an understanding of the various forces exerted upon the vehicles and occupants (humans riding in the vehicle) in multiple configurations of motor vehicle collisions (MVCs).
How an LNC’s Knowledge of Occupant Kinematics Led to a Just Result
Case example
Fifteen-year-old Josh was a restrained rear-seat passenger in a vehicle driven by his father. Only a lap belt was available in the rear seat.
Their vehicle was rear-ended at low speed while at a complete stop at a red light.
They refused emergency medical services at the scene. Josh was seen later that day by an orthopedic surgeon at which time he claimed that he had been forcefully thrown into the back of the front passenger seat. He hit his face “very hard.”
Imaging studies revealed a complex nasal fracture. Josh underwent surgical repair as recommended. Some obvious deformity and septal deviation persisted.
Josh’s father filed a lawsuit against the other driver for damages (medical bills and pain and suffering) on Josh’s behalf.
The defense attorney’s LNC reviewed the complaint, traffic collision report, medical records, and vehicle photographs.
Because of her basic knowledge of the forces involved in a rear-end collision (i.e., toward the point of impact–the rear of the vehicle), the LNC questioned Josh’s claim that he was forcefully thrown forward into the back of the front passenger seat causing impact to his nose.
She watched some crash test videos of rear-end collisions to confirm her opinion. She discussed her conclusions with the defense attorney.
A Savvy LNC’s Attention to Detail
Additional medical records, including an emergency department (ED) report from the day before the MVC, were obtained. During that ED evaluation (not previously disclosed), it was clear that Josh had hit his face on the mat during a wrestling match at school.
Emergency department X-rays revealed the complex nasal fracture, and surgery was advised. Josh’s father responded that the family did not have adequate insurance coverage for the surgery.
The defense attorney decided not to make a settlement offer. Instead, he advised his insurance company client to refer the case to the district attorney for prosecution of Josh’s father for insurance fraud.
The father eventually admitted that he had planned to “get the other driver’s insurance to pay” for the repair of Josh’s fractured nose. He did not expect the claim to be questioned following the accident. The LNC’s knowledge of basic occupant kinematics helped uncover the fraudulent claim.
Let’s look at the analysis behind this example.
Types of Crashes
Three basic types of MVCs are discussed in this blog, extracted from a chapter written by Arlene Klepatsky for the third volume of Medical record Analysis: A Guide for Attorneys by Expert LNCs.
Arlene’s chapter covers 5 types. These include the:
- Frontal MVC
- Rear-end MVC
- Lateral (T-bone or broadside) MVC
- Sideswipe MVC
- Rollover MVC
Read on for a description of the first 3 of them.
MVCs are named by the location of the primary force exerted upon the vehicle in question. A vehicle impacted in the front is a frontal MVC. A vehicle impacted on its right or left side is a lateral MVC, and so on. Each MVC type generates unique forces on the vehicle and its occupants. (Please refer to the Appendix to review crash test videos depicting the various types of MVCs.)
A basic understanding of the forces exerted in these MVC types allows the LNC to predict the likely responses of the vehicle and the occupants to these forces. This ability to predict the likely responses will assist the attorney in answering the following strategic questions:
- Do the client’s claims of injuries make sense?
- Is the client exaggerating or lying?
- Should you take or reject the case?
- Is there another explanation for the claimed injury?
- Should you hire an accident reconstruction, biomechanical, or other expert?
- What type of medical evaluations would be helpful?
- Should you settle or try the case?
Blunt Force Trauma
A common type of injury in MVCs, especially those at high speed, is blunt force trauma.
Blunt force trauma is a non-penetrating trauma that causes shock waves through the body. These may result in injuries to organs and other tissues, even at the cellular level.
In blunt force trauma from MVCs, three separate collisions occur. These include collisions between vehicles, occupants against the interior surfaces of vehicles, and occupants’ internal organs and tissues with skeletal structures.
Acceleration/Deceleration Injuries
Another type of injury in MVCs occurs because of acceleration and/or deceleration forces. With these forces, serious injuries may occur without direct impact to the occupant’s body.
Acceleration and deceleration forces can cause severe brain injury called diffuse axonal injury (DAI). This is caused by the shearing forces tearing and disrupting the brain’s axons (nerve cells).
Another injury from rapid deceleration in an MVC is tearing of the largest artery, the aorta. This can occur with anterior/posterior or lateral forces on the ascending thoracic aorta.
Rapid deceleration causes this portion of the aorta to stretch suddenly, undergoing shearing and torsion forces which may displace the heart.
Stretching forces may occur to the moveable portion of the aorta, while other portions are fixed. This results in the tearing of the vessel.
Sixteen percent of all MVCs fatalities involve thoracic aorta injury. The abdominal aorta, however, is commonly injured by direct penetrating trauma.
Understanding the First Law of Motion
In the late 1600s, Sir Isaac Newton explored and documented characteristics of movement related to various forces exerted upon objects. He called these three laws the laws of motion.
They help us predict the likely movements and force of vehicles and vehicle occupants involved in various types of motor vehicle collisions (MVCs). This chapter covers Newton’s first law of motion.
Frontal MVC
The first law of motion states that an object in motion remains in motion until acted upon (stopped) by force.
This portion of the first law helps us to envision the direction of forces to vehicles and occupants involved in frontal collisions (when a vehicle impacts something with the front of the vehicle). When a vehicle is moving forward at 30 miles per hour (mph), the occupants inside are also moving forward at 30 mph.
If the front of the vehicle hits a solid brick wall, the vehicle suddenly stops, but the occupants continue to travel forward at 30 mph. Their bodies maintain that forward motion until they are stopped by impact with the seatbelt, airbag, steering wheel, dashboard, and/or windshield.
A rule of thumb is that an occupant’s body moves (or is thrown) toward the point of impact (in this case, toward the front of the vehicle). In this situation, it appears that the occupants are thrown forward.
Injuries
Occupants are thrown forward in a frontal collision. If not protected by the deployed front airbag and properly worn seatbelts, the driver may suffer blunt trauma as they are thrown into the steering wheel and other structures on the driver’s side.
Furst (2016) points out that the front seat occupants move forward relative to the vehicle, often suffering blunt trauma to the lower extremities from impact with the floorboard and pedals. These forces also cause trauma to the hips and abdominal organs.
Sometimes, the occupant is thrown upward and into the dashboard and windshield, resulting in blunt trauma primarily to the abdomen, chest, and head. In high-impact collisions, such as head-on collisions, the entire body of the occupant may suffer from blunt trauma.
Rear-End MVC
Newton’s first law of motion also states that an object at rest remains at rest until acted upon by a force.
A vehicle may be stopped at a stoplight (at rest). The occupants are also stopped (at rest). If the vehicle is then rear-ended, it is pushed forward. The occupants in the vehicle remain at rest while the vehicle is pushed forward.
Again, it appears that the occupants are thrown toward the point of impact, in this case, toward the vehicle’s rear relative to the vehicle’s movement. The force pushes the occupants backward into their seat backs and head restraints.
Injuries
Rear-end collisions cause hyperextension injuries to the neck called whiplash. This may injure the soft tissues and/or skeletal structures of the cervical spine. (Acceleration/deceleration injuries may also occur.)
Lateral (Side-Impact) MVC
A lateral impact MVC, also referred to as a T-bone or broadside collision, often occurs at an intersection. As with other collisions, the occupant appears to move (or be thrown) toward the point of impact consistent with the first law of motion.
A lateral impact into the driver’s side door causes the driver to appear to move (or appear to be thrown) toward the driver’s door.
The vehicle is being pushed toward the right. The occupant appears to move toward the point of impact at the driver’s door. (If this does not seem entirely clear, see the lateral impact crash test in the Appendix.)
Injuries
Lateral impacts may cause intrusion of the side of the vehicle into the occupant compartment.
A lateral collision on the driver’s side causes the driver to impact the driver’s side of the vehicle at the same time this intrusion is occurring. These forces may result in blunt trauma to the left side of the head, left shoulder, and arm, left side of the chest and ribs, as well as the left hip, femur, and lower leg of the driver or left rear seat occupant.
Skeletal structures, tissues, and organs on the same side as the impact may suffer blunt trauma. On the other hand, lateral impact into the vehicle’s passenger side causes the right-side occupants(s) to suffer similar impacts to the right side of their body. Some vehicles have side impact airbags that may dampen the impact to the side of the body when deployed.
Read the rest
This is from Chapter 1, Mechanisms of Injury in Motor Vehicle Collisions, from the book: Iyer, P. (Ed.) Medical Record Analysis A Guide for Attorneys by Expert LNCs Volume 3.
Arlene Klepatsky, JD, MSN, RN, PHN, Forensic Nurse, Attorney at Law is the author of this chapter excerpt.
Order the book at this link: https://legalnursebusiness.com/medical-record-analysis-vol-3/
Pat Iyer is president of The Pat Iyer Group, which develops resources to assist LNCs in obtaining more clients, making more money, and achieving their business goals and dreams.
Have you heard the most recent podcasts on Legal Nurse Podcast? The show is in its 9th year, putting it in the top 1% of all podcasts for its longevity. Watch our podcast on YouTube at http://LNC.tips/YouTube.
Join our Facebook group, LNC Business Growth Circle, to be part of our LNC community.
Pat’s related websites include the continuing education provided on LNCEU.com, the podcasts broadcast at podcast.legalnursebusiness.com, and writing tips supplied at patiyer.com.
Get all of Pat’s content in one place by downloading the mobile app, Expert Edu at www.legalnursebusiness.com/expertedu. Watch videos, listen to podcasts, read blogs, watch online courses and training, and more.