How Does Cranial Adjusting Work? Understanding Cranial Mechanics

Understanding cranial mechanics — and what remains uncertain.

To understand how cranial adjusting works, it helps to start with what the cranium actually is: a set of bones joined by sutures, wrapped in connective tissue, and closely related to the muscles, nerves and membranes of the head, face, jaw and upper neck.

Biomechanical research has found that the living human skull can undergo small amounts of measurable deformation under load. The studies involved are limited, and the degree to which manual forces produce clinically meaningful movement remains debated in the scientific literature.

My clinical model

Here is how I think about it, based on more than 22 years of clinical experience:

When an area of the cranium isn’t moving or functioning the way I’d expect, I believe that restriction can create mechanical tension involving the surrounding tissues. My working model is that this tension may, in some patients, be associated with changes in neuromuscular function elsewhere in the body.

That’s a clinical model, not an established mechanism — it’s how I interpret what I observe, not a claim that every link in that chain has been proven by research.

Sensory input and motor output: There is good general support in neurophysiology for the idea that sensory input — including from the craniofacial region — can influence motor output elsewhere in the body. That principle is well established. What’s much less established is exactly how a specific cranial contact produces the specific changes I observe during an examination.

Why I use muscle testing

One of my primary assessment tools is muscle testing. I’ll test a muscle, apply a contact to a specific area of the cranium, and test the same muscle again. If the response changes, that gives me information I use — alongside the rest of my examination — to help decide where to focus.

I don’t treat a single muscle-test change as proof of a particular cranial finding. It’s one piece of a larger picture, and I look for a consistent pattern before I act on it.

Then I retest

After an adjustment, I go back to the same tests. Sometimes there’s an immediate, noticeable change. Sometimes there isn’t. Either way, retesting tells me something I wouldn’t know by simply assuming the adjustment worked.

Related reading

Learn more about cranial anatomy and mechanics, or see the techniques I use to address what I find.