Does your neck cause headaches or does your headache cause neck pain? This is a topic of much scientific debate, and the answer is it can be both, sometimes at the same! The challenge is determining where to start when a patient presents with one or both conditions, and whether any previous treatment has even identified and managed all of the relevant modifiable causes. And what have headaches and neck pain got to do with high blood pressure?
More about blood pressure later. Let’s first look at the stats on neck pain and headache.
We know that about 77% of patients with migraine headaches have neck pain, with migraine patients being around 12 times more likely to suffer neck pain than people without headache
The more frequent the headache, whether migraine or tension-type headache, the more likely it is that neck pain will also be present. In a recent review, 5 of 6 studies show that neck pain is a frequent occurrence during the headache component of migraine in both adults and adolescents (Al-Khazali et al 2022). Sometimes, the neck pain occurs before the headache, some patients regard it as a headache trigger, whilst for others it occurs after the headache has commenced.
Understanding the anatomical connections is essential to diagnosing and treating these problems. One of the well-recognised links between headache and neck pain has recently been proven in human research, which showed clearly that the various pain nerves arising from both the upper neck and the face converge onto the same area of the brain (Mehnert et al 2023). The nerve supply to the front half of the head is very different to the back half of the head. Specifically:
The front half of the head (including the covering of the brain known as the dura mater) is supplied by the 5th cranial nerve, the “Trigeminal nerve”. This is a very common area where headaches are felt (around the eyes or temples).
The back half of the head including the dura around the back of the brain is supplied by the nerves from the upper neck. This is the other common headache region known as an “occipital headache”.
Both the trigeminal nerve and cervical (neck) nerves converge on the same area of the brain (the “trigeminocervical complex”).
This creates the potential for referred pain, in a manner analogous to “crosstalk” between nearby electrical wires. For example, neck pain may be felt as referred pain in the head (i.e. a headache), or vice versa. This region of the brain appears to be involved in the onset of migraine headaches (Schulte et al 2020) and may, at least partially, explain the high incidence of neck symptoms with migraine headache, or why some people with upper neck problems experience recurrent headaches.
Now you are armed with the knowledge that most Physiotherapists learn. Let’s look beyond the basic knowledge of “headache” practitioners and get a glimpse into what other things contribute to neck and head pain.
Looking at the diagram above, you can easily see that the front of the neck is also supplied by nerves from the back of the neck. How many practitioners have ever even looked at the front of your neck? But it’s not as simple as saying the cervical nerves are the key. Often they aren’t the cause even when the front of the neck is involved, and one of the reasons is that there is considerable overlap in nerve supply to the front of the neck from other cranial nerves. The cranial nerves help coordinate some very tricky and subconscious movements like chewing, swallowing, breathing, speaking, moving your tongue, coughing, gagging (and sometimes several of these at once!). Now we’re getting into the visceral realm, which is what the front of the neck and jaw are all about. The front of the neck contains key visceral organs like the trachea, oesophagus, and throat to name a few. Who has examined and treated any of this for you? Learning to examine and treat these areas is not something that Physiotherapists, Chiropractors or too many others receive any training during their university courses; rather it’s advanced post-grad work that leads one into these more advanced fields.
In my earlier post I mentioned that around 25% of headache patients have high blood pressure (this is around double the rate of the population in our part of the world) (Mills et al 2020). This is especially true in chronic migraine (Mazzacane et al 2024). There are multiple reasons why blood pressure might be elevated in chronic headache patients, but let’s focus on the role of the front of the neck again. This is where the major arteries (carotid arteries) are located to transport oxygenated blood to the brain. It's where major veins (the jugular venous system) drain the blood from the brain back to the heart and thereby prevent pressure build up (think “pressure headache”). At the top of the carotid artery before it sends its branches inside the skull to your brain, the artery contains both baroreceptors and chemoreceptors which are strategically placed to monitor blood pressure and the oxygen content of the blood getting to your brain. Located just behind these receptors is the Superior Cervical Ganglion (SCG). The SCG is an important nerve plexus that sits right behind the vessels and right in front of C1, C2 and C3 (the upper 3 neck vertebrae). Why does this matter? Take a look at what the SCG supplies and what this may mean for treating headaches:
The origin of the SCG is the upper thoracic levels of the spine (usually T1-4, sometimes T1-6). This is the upper thorax / chest and associated ribs. This means that in treating your neck and headaches, we need to examine right down to the bottom of your shoulder blade at the very least. Like most chronic complaints we are no longer dealing with a localised problem. This is one reason why traditional local treatment approaches consistently fail.
The SCG sends sympathetic branches to the carotid artery system. This means it is involved in controlling blood supply to your brain. I’d say that counts as being rather important.
The SCG is the nerve supply to the baroreceptors and chemoreceptors I just mentioned. Now it is also involved in controlling blood pressure and ensuring your brain is receiving enough oxygen. Again, not a trivial thing!
The SCG sends branches to the middle cervical ganglion, which is involved in controlling the heart via the sympathetic accelerator nerves. Now it’s involved in controlling heart rate and the strength of heart contraction. Hopefully you can begin to appreciate how complex and interconnected this area is.
The SCG has multiple other connections into the cranium. As just one example it sends sympathetic nerves to the eye, controlling pupil dilation and blood flow. Think how many migraine patients have visual symptoms.
Why does this matter? The SCG sits right in front of the upper neck vertebrae and some of its nerve branches actually pass through the thin sheet of neck muscle on the front of the bones. These joints and muscles are frequently injured (for example in a whiplash accident) or become inflamed and dysfunctional for other reasons (for example a long standing forward head posture). This may result in irritation and inflammation of the SCG when there is an upper neck problem. The impact of an irritated neural structure is either “turning up” the dial on the structures it supplies, for example increasing blood pressure. Alternatively, the nerve output may be “turned down”, evidenced by a smaller percentage of migraine patients who have low blood pressure (Centeno Córdova et al 2021). Now we have one possible mechanism by which this occurs, and which skilled hands can examine and treat. This is well beyond the standard care model which is based on a joint mobilisation / manipulation paradigm circa 1970!
So, if you have chronic or episodic headaches, recurrent neck pain or a range of other things that may seem unrelated, for example blood pressure changes either high or low which is often noticed as feeling light headed or dizzy when standing up, then book in for a consultation to work out what’s going on and get it treated before it worsens. Another Physiotherapist asked me when did I first start treating the SCG, and so I checked - the first course I attended was 2003, so I've over 20 years of experience in this arena.
References:
Al-Khazali HM et al (2022): Prevalence of neck pain in migraine: A systematic review and meta-analysis. Cephalgia 42:663-673.
Centeno Córdova M et al (2021): Headache Is Associated with Low Systolic Blood Pressure and Psychosocial Problems in German Adolescents: Results from the Population-Based German KiGGS Study. J. Clin. Med. 10:1492.
Mazzacane F et al (2024): Arterial hypertension in the chronic evolution of migraine: bystander or risk factor? An overview. The Journal of Headache and Pain 25:13 .
Mehnert J et al (2023): Functional brainstem representations of the human trigeminal cervical complex. Cephalgia 45:1-13.
Mills KT et al (2020): The global epidemiology of hypertension. Nat Rev Nephrol. 2020 Apr; 16(4): 223–237.
Schulte L et al (2020): Longitudinal Neuroimaging over 30 Days: Temporal Characteristics of Migraine. Annal of Neurology 87:646-51.