People are often surprised when I suggest that their headache might be coming from the very top of their neck.
They usually say something like: “But I thought the discs in the neck wear out really early – there’s nothing left up there, is there?”
It’s a fair question. Most of us have been told that the soft centre of the neck discs – called the nucleus pulposus – dries up and becomes solid by our twenties. And if it’s “all dried up,” it couldn’t really be causing trouble… could it?
Here’s the surprising thing: that belief isn’t correct either.
A Hidden Core That Lasts
Thanks to modern imaging, researchers have been able to look much closer inside the discs than ever before. Using powerful scanning electron microscopy and advanced magnetic resonance imaging (MRI) techniques like T2 relaxation time mapping, they’ve found something important:
Even in middle age and beyond, the disc between the second and third neck bones – the C2-3 intervertebral disc – still has a soft, jelly-like centre.
It hasn’t vanished. It still holds water, and it still behaves like a tiny cushion.
This makes C2-3 quite different from the discs in the middle of the neck, which become drier and uniform with age. In fact, the C2-3 disc seems to behave more like the lower neck discs (C6-7 and C7-T1), which are known to carry a lot of load.
Small Structure, Big Sensitivity
The outer ring of the disc – called the annulus fibrosus – is very thin at the back, only about a millimetre thick. But it’s also full of tiny nerves (sinuvertebral nerve endings).
This means that even a tiny, subtle pressure change inside the disc could irritate those nerves. That irritation can send pain signals into the trigeminocervical complex (TCC) – a nerve hub that connects the top of the neck with the face and head.
And here’s the key part: if that pressure shifts from one side of the disc to the other, it can trigger pain on one side of the head, and then on the other side at a different time. Not both sides at once. Just one side at a time – but sometimes alternating.
Why This Matters
If a headache changes sides, many people (and even many health professionals) automatically assume it must be migraine, not neck-related.
But if the C2-3 disc can behave this way – and the evidence shows it can – then a side-changing headache might still be coming from your neck.
And if we miss that possibility, we might miss the real cause of your pain.
Looking for the Pattern
Here’s a helpful question to ask yourself:
“When my headache swaps sides, is it still always clearly on just one side at a time?”
If the answer is yes, and especially if it starts at the base of the skull and goes behind the eye, your upper neck is involved, even if the pain crosses sides.
The Take-Home Message
The little C2-3 disc at the top of your neck is more resilient and more sensitive than we used to think.
It hasn’t dried up. It hasn’t disappeared.
And if it’s irritated, it might just explain those one-sided headaches that seem to “play favourites” with different sides of your head.
This doesn’t mean your pain is mysterious or untreatable. It means it deserves to be checked carefully, skilfully, and with fresh eyes.
