Read this first. Some of these symptoms are emergencies.
The Centers for Disease Control and Prevention lists the following as danger signs after a head injury. If you have any of them, stop reading and go to an emergency department or call 911.
A headache that gets worse and will not go away. Weakness, numbness, or decreased coordination. Convulsions or seizures.
Repeated vomiting. Slurred speech or unusual behavior. One pupil larger than the other.
Not being able to recognize people or places, or becoming confused, restless, or agitated. Drowsiness you cannot shake, or loss of consciousness.
If you hit your head, blacked out, or felt dazed or confused at any point, you need to be evaluated by a physician for a possible concussion. A concussion is a medical diagnosis. A chiropractor cannot make it and should not try. Get it made, then come back to this page.
The honest version of what is going on
After a crash, symptoms can come from your brain, from your neck, or from both at once. They can look almost identical from the outside, which is exactly what makes this confusing.
Here is what does not get said often enough: the medical system is set up to check your brain carefully and your neck secondarily. If you were evaluated for a head injury, you were probably screened thoroughly for the dangerous possibilities and correctly told to rest. If your neck was hurt in the same event, and in a car crash it almost always is, that part of the problem can sometimes receive a less thorough look.
This page is about the neck part. It is not an argument that your symptoms are only coming from your neck. That claim gets made too easily and it can lead people to skip care they need.
Muscle spasm, tightness, and stiffness: what they actually are
These three words describe something specific, and it is not weakness or being out of shape. It is called muscle guarding, and it is a protective reflex.
When tissue in or around a joint is injured, the muscles surrounding it tighten to restrict movement, in order to keep the injured structure from being loaded further. It is the same reflex that makes the muscles around a broken bone go rigid. Your nervous system is splinting the area.
Two things about guarding are worth understanding.
It is involuntary. You cannot produce it on purpose and you cannot relax it on purpose. That is a meaningful point if anyone has suggested your symptoms are exaggerated, and it is a large part of why these symptoms are so frustrating: the harder you try to loosen up, the more clearly you notice that you cannot.
And it can persist. Guarding is useful in the first days after an injury. When it continues for weeks, it becomes its own problem. Muscles held in sustained contraction become painful, fatigue faster, and restrict the motion the joint needs in order to recover. The original injury and the protective response start reinforcing each other.
Headache that comes from the neck
Headache is one of the most common complaints after a crash, and it has several possible sources. One of them is the neck itself.
The upper cervical segments, the top two or three joints of the neck, share nerve pathways with structures in the head. When those joints are injured or irritated, pain can be perceived in the back of the head, behind the eye, or across the temple, even though the problem is in the neck. This is called cervicogenic headache, and it is a recognized diagnosis with formal criteria published by the International Headache Society.
Two honest caveats belong here. First, only the upper cervical segments refer pain into the head. The lower segments of the neck refer into the shoulder blade and shoulder girdle instead, so not every neck problem can explain a headache. Second, cervicogenic headache is a minority of post-crash headaches. The largest study following whiplash patients over a year found new cervicogenic headache in roughly eight percent at six weeks and around three percent at one year. Most post-crash headaches are classified as tension-type or migraine-like. Anyone telling you that most whiplash headaches come from the neck is overstating the evidence.
Dizziness, brain fog, and concussion-like symptoms
This is the part that needs the most care, so it is worth being precise.
The symptom list for concussion and the symptom list for a significant neck injury overlap almost completely. Headache, dizziness, balance problems, fatigue, difficulty concentrating, mental fog, light and noise sensitivity, irritability, and sleep disturbance appear on both. You cannot tell them apart by symptoms alone, and neither can anyone else.
What the research does support is that neck injury is common alongside persistent symptoms after a concussion. A 2021 systematic review in Sports Medicine found that among patients with persistent post-concussive symptoms, roughly ninety percent had cervical findings, and that neck pain at the initial evaluation increased the risk of developing persistent symptoms by between two and a half and six times.
There is also a specific concept called cervicogenic dizziness, in which impaired position sense in an injured neck contributes to unsteadiness. It is real and it appears in peer-reviewed literature. It is also a diagnosis of exclusion, which means other causes of dizziness, including inner ear conditions and injury to the balance system itself, have to be ruled out first. There is no single test that confirms it.
The conclusion people jump to, and why it is wrong
The tempting conclusion is “my concussion symptoms are really coming from my neck.” That is not what the evidence says, and believing it can be harmful.
In fact, one imaging study found that people who sustained both a mild traumatic brain injury and a whiplash mechanism had worse postural control and greater measurable brain changes than people with a brain injury alone. Having a neck injury as well does not make brain involvement less likely. If anything it suggests the event was significant.
The defensible conclusion is different and more useful: if both were injured, both need to be addressed, and the neck is the one more likely to be overlooked.
What evaluating the neck actually involves
A thorough neck evaluation after a crash looks at how the neck functions, not just whether anything is broken. That generally includes range of motion in each direction and where in that range symptoms begin, segment-by-segment assessment of the upper cervical joints if headache is present, screening for neurological signs, and, where symptoms persist, imaging taken in motion rather than at rest.
Some clinics, including this one, also use dynamic surface electromyography to record muscle activity during movement. It is important to be accurate about what that does and does not establish. It records electrical activity in the muscles as you move, which can document how guarding changes over a course of care. It is not universally accepted as a diagnostic test, and several major insurers currently classify it as investigational for that purpose. It is a way of tracking change, not proof of injury on its own.
What a chiropractor can and cannot do here
Plainly, because this matters.
- A chiropractor cannot diagnose a concussion, cannot treat a concussion, and cannot clear you to return to work, sport, or driving after one. In Minnesota those are medical determinations. If your history or examination suggests a concussion, the right action is a prompt referral to a physician, and that is what should happen.
- What a chiropractor can do is evaluate and treat the neck and soft tissue injuries you sustained in the same event, and coordinate that care with the physician managing everything else.
- Certain findings mean hands-on treatment should not proceed until further evaluation is done. Those include suspected fracture or dislocation, signs of ligament rupture or instability, neurological deficits, and symptoms suggesting a blood vessel problem, such as visual disturbance, difficulty speaking or swallowing, facial numbness, or dizziness that is provoked by particular head positions. A responsible evaluation screens for these before anything else happens.
If you are three weeks out and still not right
Persisting symptoms are information. Most people improve substantially in the first several weeks, and when that does not happen it is worth asking what has not been examined yet rather than waiting longer.
If you have been evaluated for concussion and cleared, and you still have headaches, stiffness, or fog, the neck is the most common unexamined explanation. If you have not been evaluated for concussion and you hit your head or lost time, that evaluation comes first. Not instead of looking at your neck, but before it.
Frequently asked questions
Why is my neck still stiff weeks after a car accident?
The most common reason is muscle guarding, an involuntary protective tightening of the muscles around an injured joint. It is useful in the first days after an injury and becomes a problem when it persists, because sustained muscle contraction is itself painful and restricts the motion the joint needs to recover. Persistent stiffness several weeks out is a reason for evaluation rather than for waiting longer.
Can a doctor prove my muscle spasm is real?
Muscle guarding is an involuntary reflex, which means it is not something a person can produce or suppress at will. It can be observed on physical examination through palpable tightness, restricted motion, and altered movement patterns. Some clinics also record muscle activity during movement using dynamic surface electromyography, though that technology is not universally accepted as a diagnostic test and several insurers classify it as investigational.
Can a neck injury cause headaches?
Yes. The upper cervical joints share nerve pathways with structures in the head, so injury there can produce pain felt in the back of the head, behind the eye, or across the temple. This is called cervicogenic headache and it has formal diagnostic criteria. It is one recognized cause among several, and studies applying strict criteria find it accounts for a minority of headaches after whiplash.
Can whiplash cause concussion-like symptoms?
Neck injury and concussion share nearly the same symptom list, including headache, dizziness, fatigue, and difficulty concentrating, and they cannot be told apart by symptoms alone. Neck findings are very common among people with persistent symptoms after a concussion. That does not mean concussion-like symptoms are only coming from the neck. If you hit your head or lost consciousness, you need a medical evaluation for concussion first.
Should I see a doctor or a chiropractor after a car accident?
If you have any of the emergency warning signs listed at the top of this page, go to an emergency department. If you hit your head or were dazed, see a physician for concussion evaluation. Once serious injury has been ruled out and any concussion is being managed medically, a chiropractor can evaluate and treat the neck and soft tissue injuries from the same event, working alongside your physician.
How long should stiffness last after a crash?
Most people improve substantially over the first several weeks. There is no exact number that applies to everyone, but symptoms that are not clearly improving by around three weeks, or that are getting worse at any point, are worth having evaluated rather than waited out.