Spinal Flow access points are often described as an “in-road” to the central nervous system (CNS). Anatomically, we are not physically touching the spinal cord or dura mater, because these structures are protected beneath bone.
Instead, access points work through how the nervous system receives information.
1) The body responds to light, specific sensory input
Skin, fascia, and tissues near bone contain mechanoreceptors that convert touch and pressure into neural signals that are processed by the CNS.
2) The upper neck has a real structural link into the dural system
There is an anatomical connection called the myodural bridge, linking suboccipital tissues to the cervical spinal dura mater. This supports the idea that changing tension in this region can influence the dural system indirectly, without direct contact.
3) CSF movement is driven by internal rhythms, not external force
Cerebrospinal fluid motion is largely influenced by cardiac and respiratory-driven forces. When the nervous system settles and breathing patterns change, the internal environment CSF moves through can shift as well.
In simple terms:
Access points don’t work because we “push on the CNS.”
They work because they provide a precise, repeatable signal the nervous system can respond to.
References
• Iheanacho F, et al. Physiology, Mechanoreceptors. StatPearls (NCBI).
• Enix DE, et al. The cervical myodural bridge: a review of literature. (2014).
• Yatsushiro S, et al. Cardiac- and respiratory-driven CSF motion… (2022).
• Gutiérrez-Montes C, et al. Effect of normal breathing on CSF movement… AJNR (2022).
Cerebrospinal Fluid (CSF): What It Is, How It Does Its Job, and Why It Matters
Most people have heard of the brain, spine, and nervous system…
…but very few people know there’s a clear fluid constantly moving around and supporting the brain and spinal cord every day.
That fluid is called cerebrospinal fluid (CSF).
In simple terms:
Your brain and spinal cord float in fluid.
What is CSF?
Cerebrospinal fluid (CSF) is a clear, colourless fluid that surrounds the brain and spinal cord.
It sits in:
* The ventricles (fluid-filled spaces inside the brain)
* The subarachnoid space (the space between the brain/spinal cord and the protective layers around them, where CSF flows)
The spinal canal (the tunnel inside the spine that contains the spinal cord and its surrounding fluid spaces)
Why do we have CSF? (What does it do?)
CSF has a few major jobs:
1) It protects the brain and spinal cord (shock absorption)
CSF acts like a cushion for the brain and spinal cord.
It helps absorb and spread forces so the nervous system stays protected.
2) It supports a stable internal environment
CSF helps the brain and spinal cord function in a steady, supported environment.
This includes supporting:
* nutrient delivery (bringing “fuel” to nerve tissues)
* waste transport (carrying away by-products)
* chemical balance (helping keep conditions stable for brain signalling)
3) It supports waste clearance (brain “clean-up”)
Research has shown CSF plays a role in the brain’s clean-up system, often referred to as the:
glymphatic system (a waste-clearance pathway in the brain that helps remove metabolic “leftovers,” especially during sleep)
This system appears to be more active during sleep, which is one reason sleep helps people feel mentally clearer.
Where does CSF come from?
Most CSF is produced by the choroid plexus (special tissue inside the brain’s ventricles that makes CSF).
Your body produces CSF continuously — all day, every day.
How much CSF do we have?
A simple way to understand it:
* You have about 125–150 mL (about half a cup) of CSF in your system at one time
* Your body produces about 500 mL per day (roughly 2 cups per day)
So CSF is constantly being refreshed.
How does CSF move?
CSF is not “still.”
It moves in a rhythmic way, influenced by things like:
* heartbeat (pressure waves from blood flow)
* breathing (changes in pressure through the chest and spinal spaces)
* pressure changes in the head and spinal canal (fluid responds to movement and pressure shifts)
Modern imaging like MRI (Magnetic Resonance Imaging — a scanning method that can show soft tissue and fluid spaces) has been used to measure CSF motion and flow patterns.
Why can CSF function feel “off” in real life?
When the nervous system is under stress, the body often goes into protection mode.
That can look like:
* neck and jaw tension
* shallow breathing
* rib cage stiffness
* spinal bracing (holding tension like “armour” through the spine)
* reduced natural movement through the spine
When this happens, the whole system can feel like it’s working overtime.
So… where does Spinal Flow fit into this?
Spinal Flow is a gentle approach that works with the nervous system using specific access points.
The key idea:
Spinal Flow isn’t trying to “push fluid around.”
It’s aiming to help the body reduce stored tension patterns and improve regulation.
Regulation (the nervous system’s ability to shift out of stress mode and back into calm function)
Why that matters:
When someone moves out of a protected “braced” state, they often notice changes like:
* deeper breathing
* softening through the neck and spine
* less guarding (less unconscious tension-holding)
* calmer presence
* feeling lighter or more open
* improved rest and recovery
This matters because CSF motion is influenced by rhythm, pressure, movement, and the overall environment of the central nervous system.
A simple way to explain this to clients:
CSF is the support fluid of your central nervous system.
And Spinal Flow supports the body’s natural shift toward ease, release, and regulation — so the system can do what it was designed to do.
Bottom line
CSF isn’t just “brain fluid.”
It’s part of how your brain and spinal cord stay protected, supported, and functioning properly.
And because the brain and spine are deeply connected through movement, pressure, breath, and nervous system signalling…
Supporting spinal ease and nervous system regulation can create very real shifts in how a person feels — physically, mentally, and emotionally.
References:
* Telano LN, Baker S. Physiology, Cerebrospinal Fluid. StatPearls (NCBI Bookshelf).
* Huff T, et al. Neuroanatomy, Cerebrospinal Fluid. StatPearls (NCBI Bookshelf).
* Jessen NA, et al. The Glymphatic System – A Beginner’s Guide. Neurochemical Research (2015).
* Yildiz S, et al. Quantifying respiration and cardiac pulsations on CSF dynamics using real-time phase-contrast MRI. Journal of Magnetic Resonance Imaging (2017).
* Chen L, et al. Dynamics of respiratory and cardiac CSF motion revealed by real-time MRI. NeuroImage (2015).
The Dura Mater: The Hidden Link Between the Spine and Nervous System Regulation
The dura mater is the tough, protective outer membrane that surrounds the brain and spinal cord. What makes it clinically important is not only that it protects the central nervous system, but that it forms a continuous connection from the inside of the skull, through the foramen magnum, and down the spinal canal toward the sacrum.
This continuity matters because the dura is not an isolated “covering.” It is a tension-bearing structure that can transmit mechanical strain along the length of the spine. When stress accumulates through posture, injury, repetitive loading, or long-term protective patterns, the nervous system may begin receiving distorted sensory input. Over time, this can contribute to ongoing guarding, altered movement strategies, and difficulty shifting out of protective tone.
The meninges are arranged in layers: the dura mater on the outside, the arachnoid mater beneath it (associated with cerebrospinal fluid dynamics), and the pia mater directly contacting neural tissue. Together, these layers create a protective interface between structure and nervous system function. When tension patterns persist, regulation can become harder not because the body is “broken,” but because the system is operating from defence rather than safety.
Spinal Flow works by using precise, gentle contact at specific access points to provide low-threat sensory input to the nervous system. This is not force-based work and does not rely on mechanical correction. The goal is to support regulation, so the body can reorganise tension patterns through its own neurological control rather than through external pressure.
When regulation improves, posture, motion, breathing patterns, and overall ease can begin to change, not by forcing the body into alignment, but by reducing the need for protection.
Principle:
The nervous system leads; tissue responses follow.
References
Standring, S. (Ed.). Gray’s Anatomy: The Anatomical Basis of Clinical Practice (42nd ed.). Elsevier.
Bogduk, N. Clinical Anatomy of the Lumbar Spine and Sacrum (5th ed.). Elsevier.
The Vagus Nerve, the Spine & Why “Calm” Doesn’t Always Work
Most vagus nerve conversations focus on techniques.
Breathing.
Cold exposure.
Humming.
“Stimulating” the nerve.
Helpful tools — but incomplete.
The missing piece is rarely discussed:
The vagus nerve does not work in isolation.
It depends on spinal sensory input to determine whether the body is safe.
The Vagus Nerve Listens Before It Regulates
Neurophysiology matters here.
Approximately 80% of vagal fibres are afferent, meaning they carry information from the body to the brain, not the other way around.
The vagus nerve does not calm the body unless the brain first receives clear safety signals.
If spinal sensory input is distorted — through chronic tension, protective guarding, old injury, or prolonged stress — the brain may discount vagal signals entirely.
You can breathe all you want.
The nervous system may still remain guarded.
The Vagus Nerve Isn’t in the Spine — But It Depends on It
The vagus nerve does not run down the spine.
It exits the brainstem and innervates the heart, lungs, and digestive organs.
What’s rarely explained is this:
The vagus nerve relies on spinal sensory and proprioceptive input to interpret what’s happening in the body. Joint position, dural tension, and spinal movement all inform whether the system reads safety or threat.
When spinal segments are held in protective patterns, the nervous system receives a threat-biased signal — even in the absence of conscious danger.
Why Forcing Calm Can Increase Stress
Freeze, shutdown, and collapse are often misunderstood.
They are not failures of regulation.
They are adaptive survival responses.
For some nervous systems, forcing activation — intense breathwork, cold exposure, or pushing calm — can actually increase threat, not resolve
References
Vagus nerve anatomy & afferent dominance
• Berthoud, H.-R., & Neuhuber, W. L. (2000). Functional and chemical anatomy of the afferent vagal system. Autonomic Neuroscience, 85(1–3), 1–17.
• Bonaz, B., Bazin, T., & Pellissier, S. (2018). The vagus nerve at the interface of the microbiota–gut–brain axis. Frontiers in Neuroscience, 12, 49.
Brainstem & autonomic regulation
• Standring, S. (Ed.). (2021). Gray’s Anatomy: The Anatomical Basis of Clinical Practice (42nd ed.). Elsevier.
• Kandel, E. R., Koester, J. D., Mack, S. H., & Siegelbaum, S. A. (2021). Principles of Neural Science (6th ed.). McGraw-Hill.
Spinal sensory input & proprioception
• Proske, U., & Gandevia, S. C. (2012). The proprioceptive senses: Their roles in signaling body shape, body position and movement. Physiological Reviews, 92(4), 1651–1697.
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