Cranial Adjusting Techniques: A Guide to Cranial Chiropractic

Cranial adjusting isn’t one single technique — it’s a category that includes several distinct approaches, developed by different practitioners over several decades. Understanding the differences can help make sense of what you might encounter from one practitioner to the next.

Cranial Facial Release (CFR)

CFR is the flagship technique in my cranial approach. It is an endonasal technique — meaning it works through the nasal passages — designed to provide a precise, rapid mechanical stimulus to the cranial and facial system.

CFR belongs to a broader family of endonasal, balloon-assisted cranial techniques with a documented history stretching back more than 80 years, from early intranasal work in the 1930s and 40s through Bilateral Nasal Specific to CFR today. I didn’t invent CFR, and I don’t present it as though I did — it’s the foundation I build the rest of my approach on. See the full history if you’re curious where it came from.

Nasal Release Technique (NRT)

NRT is another name for this same family of endonasal techniques, developed from the original work of J. Richard Stober, D.C. and taught more recently through Cynthia Stein, PT, M.Ed. of Conquer Concussion. I use NRT alongside CFR — the two are close relatives, and I draw on whichever approach fits what I find in a given patient.

NRT is often marketed specifically toward concussion and post-concussion recovery. I’m especially interested in working with athletes who’ve had a concussion, and this is one of the tools I use with that population — alongside a full history and exam, not as a stand-alone fix. See cranial adjusting and concussion recovery for more.

Afferentology

Afferentology is the muscle-testing framework I actually use in my practice. It grew out of Applied Kinesiology — the manual muscle-testing system chiropractor George Goodheart developed in the 1960s — refined by Simon King, a former chiropractor who became a diplomate of the International College of Applied Kinesiology in 1996 before developing Afferentology as its own approach. Afferentology focuses specifically on afferent input: the sensory signals traveling from the body toward the nervous system, and how disruptions in that input can affect muscle facilitation and inhibition. I trained and am certified through Simon King’s Association of Certified Afferentologists.

In practice, I test a muscle, apply a specific contact, and test again to see whether the response changes — the same basic approach as Applied Kinesiology-based muscle testing more generally. Research on the reliability of manual muscle testing is mixed — some applications show reasonable reliability, others don’t, and I’m not aware of dedicated research evaluating Afferentology specifically. I treat it as one useful piece of information, not a stand-alone diagnostic proof.

The idea that sensory input can influence muscle response isn’t new. Sir Charles Sherrington’s foundational work in the early 1900s described reciprocal inhibition — the way the nervous system inhibits one muscle group while activating its opposing group to produce smooth movement. More recently, researchers have studied a related phenomenon called afferent inhibition: using transcranial magnetic stimulation combined with a peripheral nerve stimulus, they’ve shown that sensory (afferent) input measurably changes motor output at the level of the brain and spinal cord. That gives a real physiological basis for the idea that a muscle’s response to a test can reflect more than raw contractile strength — it can reflect the broader sensory information reaching the nervous system at that moment.

That research is largely done in controlled laboratory settings using specific stimulation techniques, though — it doesn’t directly validate manual muscle testing as I use it clinically, or the specific mechanisms Afferentology proposes for particular symptoms. I think of it as a plausible physiological basis for why muscle testing might pick up on something real, not proof that any specific finding means what I believe it means.

Afferentology organizes this around three well-established spinal reflexes that govern muscle tone:

• The myotatic reflex (stretch reflex) — the same reflex a doctor tests with a knee-jerk hammer tap. It’s driven by muscle spindles: specialized sensory organs inside every muscle that continuously report its length and tension to the spinal cord, even at rest. That constant background signal is part of what maintains ordinary muscle tone. When a spindle detects sudden stretch, it triggers a contraction through a simple, single-synapse connection to the motor neuron — the fastest reflex loop in the body, entirely within the spinal cord.
• The withdrawal reflex — a protective reflex triggered by a painful or threatening stimulus, causing a limb to pull away while relaxing the opposing muscle group.
• Reciprocal inhibition — the same principle Sherrington described: when one muscle group contracts, the nervous system automatically relaxes its opposing muscle group, so movement stays smooth rather than fighting itself.

Afferentology’s working model is that a muscle’s response during testing can reflect how these three reflex arcs are currently behaving, shaped by the sensory input reaching them. That’s a reasonable framework built on real, well-established physiology — but it’s still a clinical model for interpreting what I find, not an independently validated account of what a given muscle-test result means for a given patient.

Percussion-Hammer technique

A percussion instrument can be used to deliver a light, controlled, rapid impulse to a specific contact point — useful in situations where a very precise, low-force input is appropriate.

The tool traces back to Robert Fulford, D.O. (1905–1997), an osteopathic physician who studied cranial osteopathy directly under William Garner Sutherland in the 1940s and later served as president of the Cranial Academy. Fulford introduced a motorized percussion device — now often called the Fulford percussor — into osteopathic treatment, and it became closely associated with his work over the following decades. It’s a separate tool from CFR and NRT, coming out of the direct-manipulation osteopathic lineage rather than the endonasal one; see that history for more on Sutherland’s influence.

In practice, I think of using the percussor a bit like dosing a medicine. The vibration speed is the part I have to match to the person: I’ll palpate the tissue and adjust the speed until I find the point where it visibly softens under the instrument at that spot. How close I hold the head to the skin functions like the dose, since the energy delivered falls off quickly as the head moves away from the tissue — closer means more, farther means less. And how often I use it on a given area, and how many visits it takes, is the equivalent of a dosing schedule. It’s a simple way to think about a tool that has more nuance to it than it might first appear.

Related techniques you may encounter

Bilateral Nasal Specific (BNS), Nasal Specific Technique, Functional Cranial Release and several other named approaches share a historical lineage with CFR and NRT — they are related but not identical techniques, developed and modified by different practitioners over time. A separate, older tradition of direct cranial-bone manipulation — associated with Sutherland, Cottam and Toftness — developed independently; see that history as well.