Are your neck muscles injured in a car accident?

Your neck muscles can become shredded in a car accident. When you are sitting in your car at a stop light, and someone hits you from behind, even with a small tap, you can be severely injured in your neck’s discs, joints, and even muscles. 

They use to think that muscles weren’t contracting fast enough during an injury to become injured in a whiplash event, but new evidence was published this year that shows that your muscles contract faster from an injury than we previously thought. 

I’ve been reading studies on whiplash injures on and off in the past 20 years. I remember reading about injury biomechanics in the late 1990s where they said that a whiplash injury occurs in 100 milliseconds, but your muscles don’t start contracting until about 200 milliseconds. We thought back then that by the time your muscles started to contract, the injury was done. 

I did this video on whiplash 8 years ago.

We thought that when you were unaware of the impending injury, that you would be unable to contract your muscles fast enough, and you would get all ligament injury. We knew back then that when you see in the rear view mirror a car approaching too fast, and you braced for impact, you would have less ligament damage, but more muscle damage. This was a better scenario, we thought, and we still believe, because muscles heal a lot faster than ligaments, discs, and joints in the spine. 

It turns out that when you are rear ended, the muscle going diagonal from your ear to your collar bone called the sternocleidomastoid muscle contracts really fast with impact. It only takes 60 milliseconds after impact from behind to make that muscle go through its peak contraction. Your head will still be whipping backwards at this time, and your head won’t stop whipping backward until about 113 milliseconds. This SCM muscle, as we abbreviate it, contracts to slow down your head movement. And as the muscle is bracing your neck, it is being pulled apart in fast-motion, causing your muscle fibers to tear apart. 

After the SCM muscle is being shredded with this injury, The trapezius muscle, the “traps”, start to contract and almost immediately contract to their full force. The traps are shredded at the 90 millisecond mark, and your head is still on its way backwards to meet the head restraint in your car. 

Now, as your car seat is busy pushing your low back and mid back forward, and your life starts flashing before your eyes as glass shatters and metal buckles, and as your front neck muscles are holding on for dear life, the muscles behind your neck start to then contract, and they react last. The erector spinae muscles start contracting 53 milliseconds after impact, and they contract at their peak at 149 milliseconds. This is just after your head is at its peak acceleration at 113 milliseconds. 

The whole event is over in only 200 milliseconds. Yep. 0.2 seconds. 

As your muscles are grabbing on, they are torn apart through negative, eccentric muscle contraction. Your muscles are trying to contract, to shorten their length, but the car accident is sending forces to make your muscles lengthen. 

What this tells me, as a clinician, is this: When you are injured in a car accident, and you are hit from behind, you’re going to be suffering soft tissue injuries to the muscles and ligaments. Your muscles are the active tissue, that contract and brace you for injury. Your ligaments are passive parts, that brace and hold your spine no matter what happens to the muscles. They are both damaged. 

And we know that muscles hurt a lot when injured, but fortunately they heal pretty quickly. But picture this: Your ligaments are also damaged, and they take forever to heal. Sometimes up to a year. They heal slowly and poorly because they have a limited blood supply. 

All of these areas are very pain sensitive, and can interfere with your brain’s central sensitivity, which is a very unfortunate side effect of these injuries than can have lifetime consequences. Neck pain is already the 4th leading cause of disability among working adults, and this will only make matters worse. 

So what should you do if you are injured? If it were me, I would do everything I can think of to facilitate the best soft tissue healing. I would immediately try to restore movement in my neck, spine, and shoulders as soon as I could. I would also start to strengthen the damaged muscles as quickly as possible in my neck, probably by performing kick-ball exercises. I would support myself with good nutrition principles, which would be as anti-inflammatory as possible. And among other things, I would consult with my own chiropractor to get third part coaching and treatment for this. 

Rear ended, your muscles react in a certain time.

Whiplash Injuries

Whiplash injuries are injuries to your neck when you’ve had a car accident. Car accidents that cause neck pain are really common, as they happen about 5 million times a year in the United States. Sometimes they are mild, and too many times, they can be disabling.

Your doctors have probably been traditionally well-trained in pathological conditions that happen in your neck, but they might not have been very well trained in motor vehicle collisions and how they can affect your neck. They might not understand how they happen, how to diagnose them, how to manage them, and what to tell you for a prognosis. Further, they might not know much about litigation–the med-legal part of the injury.

Personally, I have been a victim of a rear-end collision a few times in my life. The first happened while I was in high school. A car hit the back of my 1981 Buick Regal, and I in turn, hit the car in front of me. As a kid, I liked to recline my car seat a little bit too much, which is probably not very wise in hindsight, but that might have saved me from having a lot of neck trauma. The second time, I was in a small sports car in about 2005, and I was hit from behind by an SUV. I made it out okay with that one too, but I might have been pretty sore the week following the injury. The third time, I have been hit from behind was in 2018, and at the time of this writing, I am still sore from  the injury. I was at a complete stop on Highway 37 in Sonoma at Sears Point in my Prius when a kid in an SUV/Minivan hit me with enough force that I remember being propelled into the pickup in front of me. All of this collision happened in a blink of an eye.

Vehicle Dynamics

A car crash is a very brief event. They only last about the blink of an eye. 100 milliseconds. Your neck muscles only respond in about 200 milliseconds, which can cause problems that I will talk about later.

When you hit someone from the front, there are three ways that the energy from your speeding vehicle absorbs the speed and energy from your car:

  • The first crush zone is the area between your bumper and the car’s engine.
  • The engine compartment absorbs the energy next, and this part is much stiffer than the bumper crush zone.
  • The structures behind the engine, but in front of the firewall where your dash board is mounted is the third area of impact absorption, and this is less stiff than the engine compartment, but stiffer than the bumper.

If you are the driver of the “bullet” car, your body will continue to move along at the speed you were traveling while your car is crushing in these three zones. Until it is caught in your seatbelt or airbag. Or windshield or steering wheel.

A body in motion will stay in motion until acted upon by another force.

As your car suddenly stops against the car in front of it, you have about 4-18 inches of wiggle room until your body meets the seatbelt in front of you, or another part of the car. Women can have worse injuries than men because women tend to have their seats pulled farther forward, and places their bodies closer to the steering wheel and other interior car bits. Either way, your seatbelt will be the first point of contact, and the largest source of direct blunt injury to your body.

If your body hits parts of the car’s interior, you will have a direct blunt trauma to a body part. In your neck, though, you’ll get a sprain/strain type of injury.

Side Impact

About a third of all car accidents are side impact injuries. Same crash time: 100ms. In most cars, when you are hit, you have 8-12 inches of car door and space before the impact hits your body, and the peak time for injury happens at 35ms. The side impact will compress your car’s suspension on the far end, which can lift your car at the point of impact. If you are hit from the side, your torso will load at the side of the collision and your head will lag behind, leaving you with jammed neck joints, and strained neck muscles.

There’s no bumper and engine to absorb these kinds of injuries, so they can be pretty devastating. When it comes to your neck, the most commons part of the neck that gets injured is at C5-C6. The discs in your neck are primarily injured, followed by the facet joints, then your muscles. If you are sitting in the side of the car closer to the impact, you will get injured more than if you were sitting on the other side. You’ll have 1-3 times more risk of injury.

High Speed Rear End Collisions

“High Speed” rear enders are classified as such when the car’s speed is more than 10 miles per hour. Most research on rear end crashes study 2 to 5 mph collisions.

As a rear-end collision occurs, the energy of the crash is absorbed by both the bullet car, and the target car. Sometimes the target car will absorb the impact through the back hatch or trunk. Sometimes the bullet car will absorb impact through the hood. Usually the impact will submarine the suspension of the target car.

As the collision’s forces travel through the frame of the car, the person sitting in the target car will slam into the back of their seat as the seat travels forward with the collision. The forces push your seat back into your mid-back. Your torso pushes forward, leaving your neck behind, then your neck finally catches up by either hitting the head restraint (head rest), or by a shearing force in your neck.  If your neck has to absorb the crash energy, then your neck structures will have to bear the trauma. Discs, facets, ligaments, and muscles will have to be injured as your 12-16 pound head is pulled forward.

If this injury is severe enough, and if you’re lucky, then the pin that secures your seat back will break, and your seat back will break away, absorbing more energy, and causing you to recline as the impact slows down (decelerates.) In some cases, a broken seat will let you walk away from a crash without injury1.

A rebound often occurs. After the first impact has caused you to spring off of the back of your seat, you could hit the steering wheel or dash board, and you could be further injured. This happens in 28 percent of all injuries2.

Neck Injuries in High-Speed Crashes

Your neck gets injured by your seat back punching your back, and your head moving backward. Your head might hit the head restraint, or if your car’s seat if designed poorly, it will pitch up and over the head restraint, pushing it down into it’s low position. In old pickup trucks, your head will hit the rear window.

Then you rebound, and your head moves forward. Maybe your head will hit something, or maybe your neck joints will absorb the impact.

One study shows that when your seat back hits your mid back, it causes your spine to compress at the junction between your neck and upper back. Your mid back gets taller, and it compresses the discs in your neck, creating an injury.

There have been many studies on low-speed collisions on humans, for safety, and it’s been said that you can take the low speed results and magnify them the faster the collision is.

Here are the factors for injury:

  • Head turned
  • Seat back stiffness
  • Elastic rebound of the seat back
  • Female passenger (smaller neck to support the head, compared to men)
  • Different car models
  • Being unaware of impact
  • Being too tall
  • Being too short
  • Being out of position
  • Being elderly
  • Movable head restraints (as opposed to fixed, like in a Volvo or Porsche)
  • The car does not crumple, stays undamaged on the bumper
  • Change of velocity of the target car (does it get thrown forward very far?
  • Small car hit by large truck
  • Pre-existing medical conditions (osteoarthritis, disc degradation, thyroid disorders, spinal surgery, spinal stenosis, diabetes)

Next: Clinical Presentation of Whiplash Injuries


Morris A, Thomas P. Neck Injuries in the UK Co-operative Crash Injury Study. SAE. 1996;(962433).
Farmer C. Effects of Head Restraint and Seat Redesign on Neck Injury Risk in Rear-End Crashes. Traffic Injury Prevention. 2010:83-90.

7 tips for improving office ergonomics.

  1. Check your monitor height.
  2. Check your monitor distance.
  3. Fix your seat back angle.
  4. Check your keyboard position.
  5. Adjust your seat pain angle.
  6. Get a foot rest.
  7. Ask your employer for a standing workstation.

While in the standing position, you can provide variety to your stance by using a fencer’s stance. You can actively stretch your legs by doing calf stretches or hip flexor stretches. Bring a soccer ball to work to adopt a Captain Morgan stance. This take pressure off of your hips and low back.

What kind of pillow should I use?

The topic of what pillow to use for neck pain or posture comes up a lot in our clinic, and there’s never an easy answer that will apply to all people. The first answer is always, “it depends.” But that’s not very rewarding, so let’s go over some principles.

Principle #1: Keep your spine in a neutral position when you sleep. 

Whether you are a side-sleeper, or a back sleeper, you need to find a pillow that will allow you to keep your spine neutral. If you are a side sleeper, you will want to have a firmer and thicker pillow than if you sleep on your back. If you think about it, when you are on your side, your pillow will need to meet the space between your shoulder and your neck. It’s got to be thicker.

If you are on your back, you won’t need to have as much space between your head and the bed. Some people who are back sleepers even get away without any pillow at all. You’ll want to get yourself a nice, thin pillow if you are on your back. And, this pillow might even the kind that is super thin, but has a little more support for your neck.

To keep your spine neutral, you don’t necessarily need to know the way the curves in your spine are structured. You won’t need to know about the cervical lordosis and the thoracic kyphosis, for example. You just need to find a way to avoid side bending in your neck or low back, and avoid rotation in your neck or low back. When you’re on your back, your ears should be on the same plane as your shoulders and your hips. If I were to draw a line between these points, the line should be straight. In other words, you should avoid the trap of having your head propped up to high on a thick pillow. Back sleepers need to have a firm enough support in the rest of the back to avoid a dip between your shoulders and hips.

If you’re a back sleeper, the exception to keeping your neck horizontal, of course, is if you have sleep apnea. If you have sleep apnea and you sleep on your back, then your throat will tend to close down on your airway and restrict breathing. Sleep apnea is a special case where you might want to even prop up your upper back with a special wedge that will elevate your whole upper body, while still taking care to keep your spine neutral.

If you’re a side sleeper, it’s common to not have enough support for your head and neck. When on your side, you don’t sleep on the very point of your shoulder–that would be uncomfortable. Rather, you tend to sleep with your arm forward on top of the flat part of your shoulder blade. This can interfere to some degree with your resting shoulder position, and it’s why side sleeping is not as good as back sleeping. But if you do sleep like this, you need to visualize the distance between your shoulder and your neck. Too little support, and tour head will rotate and bend to one side, creating neck problems. Too much support, and your neck is elevated too much. Sleeping like this often causes an acute kink in your neck that be painful for a week.

Side sleepers often do well with a shredded memory foam pillow, which combines the thickness of memory foam with the soft breathability of a pillow with a looser type of material. The Chiroflow water pillow also tends to be a good choice for side sleepers, as you can change the thickness of the pillow by adding or draining water from the water pouch.

Principle #2: Don’t sleep on your stomach.

So what do you do if you have the bad habit of sleeping on your stomach? If you sleep on your stomach, you need to stop. There is no way to go face down and keep your spine neutral if you still want to breathe. Even if you borrowed a face cradle from your massage therapist, you won’t be able to comfortably sleep with the pressure on your face. Stomach sleepers turn their head at night to breathe. You have to breathe. And, having your head turned all night long is even worse than having a head-forward posture. It’s horrible. Having your head turned to one side affects the length and tone of the neck muscles. It’s positioning the joints in the neck in a way that sends a continuous neurological signal to your brainstem and cerebellum for postural processing, and the garbage-in-garbage-out signal processing is creating hard wiring that will hove profound effects on your balance, posture, and athletic abilities.

If you are a stomach sleeper, you will come to our clinic with tightness in your upper neck and an unconscious postural head-turn. When I check your neck, I will feel the spinous process of your C2 bone rotated all the way to one side. this will affect the tightness throughout your neck and probably your whole spine. This will give you a much higher likelihood of developing headaches. Tightness in your upper cervical complex of muscles will affect the neurological circuits going into your brainstem, and it will directly compress the nerves at the back of your head called the greater occipital nerve, and can cause pain from nerve compression. You can’t just get this adjusted back to normal very easily, either. Your chiropractor can’t work against 8 hours of sleep every night for 7 days a week with only a 5 minute weekly adjustment.

Don’t sleep on your stomach.

Principle #3: Allow yourself time to get use to your new pillow. 

If you’re having neck pain and you want to be proactive about every aspect of your life, and you are getting what you think will be the best pillow, you might be disappointed at first. You need to allow yourself to adapt to your pillow for a few weeks before you make a judgement about how it is working for you. Even when you first lay yourself down to sleep, you need to allow yourself 10-15 minutes for your neck muscles to fully adapt and relax into your pillow. For this reason, you can’t really tell what kind of pillow is best for you with a brief squeeze at the store. But, when you do get a new pillow, allow yourself to get use to it for a few weeks.

Also realize that when you make a change to your pillow, but change nothing else about your lifestyle, you might be feeling the effects of your work ergonomics or your recent neck pain episode, but since your new pillow isn’t bringing you relief, then it’s easy to say that it isn’t working for you. During the day, you are active. You are moving around, and your movement receptors in your muscles and joints are bringing signals to your spinal cord and brain even when you are merely sitting. Your movement throughout the day triggers pain-relieving signals in your spinal cord and brainstem, and this makes it so you don’t feel the pain as much as you do when you wind down for the day. When you are laying in bed, you might feel the throbbing from an injury, or the ache from tight muscles more. And even if your pillow is supporting you properly, you can still feel the effects of your waking hours.

Principle #4: You pillow surface should be soft.

As you use your pillow, and you are counting on a good night’s sleep, you will want to minimize the pressure points on your skin. Some pillows are just too hard on the surface, and this surface hardness will blanch your skin. It will put pressure on your skin, and it will starve your skin of the blood flow. The capillaries will be compressed. This is usually not harmful for the long term, but it will be uncomfortable. If you were to measure out the pressure levels on certain parts of your head, neck, and face while you are lying on your pillow, you don’t want any pressure points, because these pressure points over time will turn achy on you. You want the weight of your head to be evenly distributed. This is particularly important if you are a side-sleeper. If you are on your side, and your pillow is pressing against your cheek, and starving your cheek skin of blood flow, you are causing wrinkles and impairing your ability to recover from sun damage and facial muscle tension from your day. You are going to want to allow some recovery.

In our office, we carry the Chiroflow pillow. This is a pillow that has a water pouch built into it, and you can adjust the amount of water to your level of comfort. With the water pouch, under the layer of soft fill, the water will shift out of the way when you reposition yourself on it. The dynamic way that the pillow changes shape has been shown to reduce the forces translated to your head, neck, and face when you are sleeping.

Principle #5: Reduce the pressure on your shoulders and hips.

When you are lying on your side, common pressure points include your shoulder and your hips. If you are feeling hip pain, and perhaps developing a bursitis type of pain on the side of your hip, you are either going to want to train yourself to be a back sleeper, or you will want to get a softer surface for your mattress. This mattress topper can be memory foam, soft synthetic fill, or cotton. It can be 1″ to 4″ in depth, and it will all depend on your budget. If you are currently battling a pain in your hip, then you might want to go softer and deeper from a strictly orthopedic perspective. It might be worth it to get a topper that is a little softer than you otherwise would need to help you take care of the problem.

You’ll also want to experiment with other supporting pillows for your body to minimize pressure points on your shoulders and hips. While sleeping on your side, a pillow between your knees will help keep your knees in line with the hip joints in your pelvis. If you are able to avoid too much angle between your hips and your knees, this will help you avoid a tendinopathy that you can develop across your hip joints because the tendon is stretched at an unnatural angle. Some runners will blame their tight TFL (tensor fascia lata) and IT (iliotibial) band on their running, but it can also be affected by their sleeping posture. The IT band runs from your hip bone on your side, down your thigh to your knee, and it provides added stability to your hips, thighs, and knees. It’s common to have a tightness develop in your IT band, and therapists often try to fix it by stripping the muscles and fascia. In effect they are beating it all up, but they are not addressing postural issues that are a more direct cause of the pain.

Work on your upper back mobility to reduce neck pain.

Neck pain is a common source of disability that affects your every day life, while simultaneously being non-threatening to your life. It’s a form of suffering that affects you in the moment, but it is not an emergency. But with your quality of life being affected so much, now is also the time to do something about it.

My tip of the week is that you need to pay attention to your neck’s foundation. Your neck’s foundation is your thoracic spine. Your mid back. Your shoulders and that space between your shoulder blades. When you have lost mobility in your upper back, then your neck will surely suffer as a result. Stiffness in your back causes your neck to move forward into a forward head posture. This makes your neck muscles work harder. This creates instability in the joints in your neck. This complex of problems can create a chronic neck pain condition, and it can cause headaches.

When your neck is forced forward from your upper back being tight, the muscles such as the trapezius, the levator scapulae, the paraspinal muscles, and the scalene muscles all have to tighten to brace the neck, and to pull their supportive load. This chronic neck tightness can create trigger points in your muscles, it can create a tendonopathy, and it can degrade the joints in your neck. Every inch that your neck goes forward can multiply the forces that your neck is forced to hold, and this creates more stress and instability as time goes on.

Many of us are stuck behind a desk, sitting and looking at a computer monitor for hours at a time, without many breaks in between. This long form of abuse to your own back will cause your upper back to become stiff. You’re in a constantly hunched position. This is spinal flexion without a lot of time going back, straightening out in extension.

You’re going to need to extend your spine once in a while. You’re going to need to mobilize your spine.

One of the most common ways that my patients mobilize their backs is by using a foam roller. Foam rollers are great because they provide a comfortable surface on which to extend your spine. You ca lay the roll across your back, and you can reach out wide with your arms to open your chest and roll your back back at the same time. It’s a great way to provide a surface massage on your tight spinal muscles. But more importantly, getting the joints in your back to open up and to mobilize is an effective way to provide better support for your neck. As a bonus, the deep stabilizing muscles of your neck are usually very active during this exercise.

Another excellent mobility drill is one that I teach many of my patients when I identify a lot of stiffness in their upper backs. This one involves you getting on your knees, kneeling against a bench, bed, or couch. And you’ll need a stick to hold on to, like a broomstick handle or a golf club. You start by kneeling against the bench in a prayer position, elbows on the surface of the bench, and your hands palms up holding on to the stick. While in this position, rock back so your arms go overhead, and bend your elbows so your hands and that stick goes behind your head. You will feel a great stretch in your latissimus muscles on both sides, and you will feel a great passive extension in between your shoulder blades.

Spinal manipulation is not something you can do at home, but when you get a great chiropractor that can provide the right amount of movement to your upper back, that provides an immediate, palpable relief to that tight feeling of pressure between your shoulder blades. If you have neck pain, and you haven’t explored this approach, this type of therapy along with stabilizing exercises is a great combination.

Any time you can get yourself into a doorway stretch or some other reaching type of stretch or movement with your arms and shoulder, you are helping your upper back mobility. Movement of the upper half of your body in general is an important thing to do if you are stuck in one position at work all day.

Todd Lloyd, DC