How Can a Brain Injury Be Caused By a Simple Accident?

Hi, I’m Matt Powell. I am a car accident attorney and the proud owner of MattLaw, a personal injury law firm in Tampa, Florida. Today, I would like to share some information about the physics involved in car crashes and how even simple car accidents can cause whiplash and mild traumatic brain injuries.

Newton’s laws and their role in car accidents

Sir Isaac Newton described the laws of motion in 1687. The first Law of Motion basically says an object at rest will remain at rest until it is acted upon by an outside force. An object in motion will continue in motion with the same speed and direction unless acted upon by another force, which is called the Law of Inertia.

Newton’s first law: Inertia

In simpler terms, inertia means that there is a natural tendency of objects to keep on doing what they’re doing. All objects resist change in their state of motion.

Newton’s second law: Acceleration

Sir Isaac Newton’s second law of motion basically says that acceleration is produced when a force acts on a mass, and the greater the mass of the object being accelerated, the greater amount of force it will take to move it.

What happens in a rear-end collision?

With these two general explanations of the laws of physics, let me show you what happens in a simple rear-end car crash before the moment of impact. The person inside the car and the car itself are resting without motion. As soon as the car is hit from behind, the mass and energy from the moving, at-fault car begins to transfer energy into the stopped car.

 

What most people don’t understand is that the body of the person sitting in the stopped car will not move immediately with or as quickly as the car they’re sitting in. Instead, there is a lag in time before their body starts to move. In this graph, we have time going along the bottom, with G-forces on the left. The steel frame of the car being hit will begin to accelerate forward from the impact.

 

 

However, the person in the car will resist moving due to Newton’s law of inertia. What will happen is the vehicle will begin to move before the occupant. The vehicle may actually move several inches forward while the person’s torso begins to increase pressure against the back of their car seat.

 

Image 6: Car Crash Physics – Driver Position Hands of Steering Wheel

The whiplash effect

Note in the above picture how the driver’s hand is off the steering wheel. The pressure from the seat shoots the torso of the human body forward like a diving board propels a diver. The torso moves first, and because your head is somewhat like a bowling ball supported only by your neck, your head will remain motionless for a few more milliseconds. So the car moves first, then your torso moves out from underneath your head.

 

Next, your head must suddenly accelerate to catch up with the car and your torso. This very sudden acceleration of the head causes two points of stress in your neck. The first point is at the cervical vertebrae, C5 and C6, and the other stress point is between the cervical vertebrae, C1 and C2. These two areas of our neck usually get the most damaging levels of force. Oftentimes, this tears or permanently stretches the ligaments that hold the vertebrae in their proper place. The result is pain and suffering.

 

Understanding the brain’s vulnerability

The exact same laws of physics that cause whiplash can also cause mild traumatic brain injuries. Our brain is very complex and made up of two types of brain cells. The center of our brain is called white brain matter, and then there is the gray brain matter, which surrounds the white matter. Our brains are floating in a liquid, which is cerebral spinal fluid. All of this is housed inside our very hard skulls.

It’s important to know that the white brain matter is much denser and heavier than the gray brain matter.

 

 

There are billions of cells in our brains, and there are axons that connect the gray and the white matter. These axons transmit information from one part of the brain to another.

 

 

When a person is suddenly hit from behind, like in our example, the head, which is the last part of the body to move in a car crash, has to accelerate forward quickly to catch up to the car and the torso. The back of the person’s head may also hit the headrest, which further increases its acceleration.

 

Since our brain is floating in liquid and consists of two different types of brain cells, one heavier than the other, each part of the brain accelerates at a slightly different time and rate. The difference in the movement between the white and gray matter causes diffuse axonal shearing. This is a medical term that explains how the connecting axons are damaged from the shearing between the gray and white brain cells.

 

Your brain cells follow Newton’s first law of physics, and your brain remains still while the skull is being accelerated forward by the headrest. The brain’s gray matter is accelerated first because it’s closer to the back of our skull, is softer, and has less density than white brain matter. The pressure from the gray brain matter begins to apply force to the white brain matter, and then the white brain matter begins to move forward to catch up with the gray matter.

 

Now, as your head is traveling forward, it will suddenly stop when your seatbelt, which holds your torso in your seat, causes your head to jerk backward. Meanwhile, your brain is still moving forward inside your skull and goes through the same traumatic forces a second time. Again, this causes shearing of the axons as the gray and white matter move at different times and speeds.

 

 

Also, if there’s some rotation of your head – which may happen if your head is slightly turned before or during the crash – then the shearing to your brain cells can be even worse.

This type of brain injury can happen in less than a quarter of a second. Most of the time, people don’t even lose consciousness. They may not even have a bump on the back of their head, but they may feel dazed, groggy, confused, agitated, or experience many other feelings from this traumatic brain injury.

Why many brain injuries go undiagnosed

Unfortunately, many mild traumatic brain injuries go undiagnosed. It is not uncommon for people to feel an adrenaline rush in their bloodstream. Due to the chaos associated with a car crash, they may think they’re okay and not seek immediate medical care, even though they have just experienced a very life-changing injury.

In my 30 years of experience as an injury lawyer, the injured person is usually the last one to realize or know that they have suffered a mild traumatic brain injury. It’s usually their family or friends who notice they are having a difficult time selecting words in a conversation or being able to concentrate or remember things.

How brain injuries are diagnosed

Normal X-rays, CT scans, or MRIs will not show a mild brain injury because our brain cells are so small. These tests are good at showing the anatomy of our brains but not our brain’s inability to function.

Instead of basic radiological studies, doctors must use more sophisticated tests to measure the function, or lack of function, of our brain. They can use specialized MRI with DTI, which stands for Diffusion Tensor Imaging, or SWI, which stands for Susceptibility Weighted Imaging. Your doctors may even order a C.T. SPECT scan, which can measure how your brain cells are functioning by measuring the amount of sugar your brain cells are using.

 

 If certain brain cells are not using sugar because the cells are damaged, a C.T. SPECT scan will show this loss of brain function. In this image, the blue areas of the brain are damaged cells. There are other tests that also measure brain function, including SPECT scans and an MEG, which stands for magneto encephalopathy and is one of the most sensitive ways to measure brain function. An MEG is an advanced, non-invasive brain imaging test that measures real-time brain function by detecting magnetic waves generated by neuronal activity. Unlike traditional scans like MRIs or CTs, which only capture static images, MEG identifies functional disruptions in the brain, helping diagnose and pinpoint damage from head trauma. This cutting-edge technology is helpful in both medical diagnosis and building legal cases involving traumatic brain injuries.

In addition to the radiological tests and studies that can be used to measure a person’s brain function, there is also neuropsychological testing, which measures the brain’s performance. Neuropsychologists are trained experts in assessing the function of the brain through administering psychological tests. These tests require us to use different parts of our brains in different ways. And if we have a deficit, it will show up in testing.

Why legal help matters after a brain injury

As you can see, a mild traumatic brain injury is an extremely serious injury, and it requires extremely sophisticated testing, as well as very good doctors to appreciate and understand when someone may be suffering from such an injury. At my law firm, we can help you find the doctors you need. I hope you have found this information helpful, and if you have more questions about brain injuries, please fill in my contact form or call me at (813) 222-2222  or visit my law office in Tampa. Thank you for reading.