Concussion, CSF & the Glymphatic System: What Does the Research Show?

Read about the wider assessment and treatment approach for persistent post-concussion symptoms.

For many years, concussion research focused primarily on what happens to neurons following injury.

That picture is becoming broader.

Researchers are now also investigating changes in the environment surrounding the brain — including cerebral blood flow, cerebrospinal fluid (CSF), neuroinflammation, meningeal lymphatic pathways and the glymphatic system.

This is particularly interesting in people with persistent post-concussion symptoms such as brain fog, fatigue, headache and head pressure.

At Cranial Solutions, it is also relevant for another reason.

These fluid systems operate within a physical anatomical environment formed by the cranial base, dura, blood vessels, upper cervical region, craniofacial structures and the respiratory system.

That raises an important question:

Could the mechanical environment surrounding these systems also be relevant following concussion?

This article explores what current research tells us, alongside the biomechanical relationships we investigate clinically at Cranial Solutions.

Cerebrospinal Fluid: The Brain's Changing Fluid Environment

Cerebrospinal fluid is the clear fluid surrounding the brain and spinal cord.

It performs several important functions, including:

• cushioning and protecting the central nervous system
• contributing to chemical stability
• transporting signalling molecules
• participating in nutrient and metabolic exchange
• interacting with pathways involved in waste clearance

CSF is continuously produced and renewed.

Although only around 150 mL is present within the adult CSF spaces at a given time, several hundred millilitres can be produced over 24 hours.

This means CSF is not a static pool of fluid.

It is continuously produced, circulated and reabsorbed as part of a dynamic physiological system.

What Moves Cerebrospinal Fluid?

CSF movement is dynamic and pulsatile.

Several physiological forces contribute to this movement, including:

• cardiovascular pulsation
• respiration
• pressure gradients
• body position
• movement
• changes occurring across the sleep-wake cycle

Two rhythmic mechanical processes are particularly interesting to the Cranial Solutions approach.

The first is respiration and its influence on thoracic, venous and CSF pressure dynamics.

The second is the cranial rhythmic motion described within cranial osteopathy.

Looking at these together provides an interesting model for considering the mechanical environment surrounding the brain.

Nasal Breathing, Thoracic Pressure and CSF Movement

Breathing is not only about moving air into and out of the lungs.

Every breath creates rhythmic pressure changes through the chest, venous system and spinal canal, and these pressure changes contribute to the movement of cerebrospinal fluid.

During inspiration, expansion of the thoracic cavity alters intrathoracic pressure. This influences venous blood movement and creates pressure changes transmitted through the spinal and cranial compartments.

Respiration is therefore one of the recognised physiological drivers of pulsatile CSF movement.

This is particularly relevant to Cranial Solutions because nasal breathing is something we pay close attention to — and something that often improves substantially following NasalRx.

Why Nasal Breathing Matters

Normal nasal breathing does considerably more than simply provide another route for air to reach the lungs.

The nose provides resistance to airflow and helps regulate breathing mechanics.

Nasal breathing can encourage a different respiratory pattern from habitual mouth breathing and may support more effective diaphragmatic respiratory mechanics.

When nasal airflow is restricted, people may compensate by breathing predominantly through the mouth.

Habitual mouth breathing can be associated with changes in:

• respiratory pattern
• diaphragmatic mechanics
• rib-cage and thoracic movement
• head and neck posture
• tongue and jaw position
• upper airway mechanics

For Cranial Solutions, this creates another potentially important connection between the nasal airway, craniofacial mechanics, respiratory mechanics and the pressure environment influencing CSF movement.

The Thoracic Pump and CSF Flow

The chest can be thought of as an important pressure-generating component of the body's fluid systems.

With each respiratory cycle, changes in intrathoracic pressure influence venous return and pressure relationships extending between the chest, spinal canal and cranial cavity.

These respiratory pressure oscillations contribute to CSF movement.

From below, breathing therefore produces repeating thoracic and respiratory pressure changes.

Within the head, there are also pulsatile vascular forces and the cranial rhythmic movement described within cranial osteopathy.

All occur within an interconnected system containing arterial blood, venous drainage, CSF and lymphatic pathways.

This makes respiratory mechanics particularly relevant when thinking about the physical environment surrounding the brain.

Nasal Breathing, Mouth Breathing and the Cranial Environment

The distinction between nasal and mouth breathing may also be important.

Nasal breathing produces different airflow resistance and respiratory mechanics from breathing predominantly through an open mouth.

There is emerging research examining relationships between respiration, nasal airflow, neural activity and CSF dynamics.

We should not assume that simply changing someone from mouth breathing to nasal breathing automatically increases glymphatic clearance.

But the physiological relationships are compelling enough that breathing pattern deserves a place in the broader model.

At Cranial Solutions, we are particularly interested when a patient presents with a combination of:

• restricted nasal airflow
• habitual mouth breathing
• altered craniofacial mechanics
• head pressure or headache
• poor sleep
• brain fog or fatigue
• persistent symptoms following concussion

Rather than viewing these as completely unrelated findings, we assess how the nasal airway, craniofacial mechanics, cervical region and respiratory system are functioning together.

Why NasalRx Is Particularly Relevant to Nasal Breathing

One of the most consistent changes we see following NasalRx is an improvement in nasal airflow.

For some patients, the change can be substantial.

NasalRx mechanically influences the internal nasal passages and surrounding craniofacial structures. As restriction reduces, patients frequently describe being able to breathe much more freely through the nose.

This matters at several levels.

Improved nasal airflow may make nasal breathing easier and reduce reliance on habitual mouth breathing.

That may influence the way the diaphragm, rib cage and thorax participate in respiration.

And because respiratory pressure changes are one of the recognised drivers of CSF movement, improving the mechanical conditions for effective nasal and diaphragmatic breathing may also improve the wider pressure environment in which cranial and spinal fluid movement occurs.

This provides an important physiological bridge between what we frequently observe following NasalRx — improved nasal breathing — and a recognised driver of CSF dynamics: respiration.

Cranial Rhythmic Motion and the Sphenobasilar Region

Within cranial osteopathy, practitioners have described and worked with a rhythmic movement of the cranial system for many decades.

This is commonly discussed as part of the primary respiratory mechanism, with the sphenoid and occiput — and their relationship at the sphenobasilar region — playing a central role in the cranial rhythmic pattern.

Clinically, this is described as a cyclical expansion and relaxation through the cranium.

At Cranial Solutions, we consider the quality, symmetry and amplitude of cranial movement to be relevant to the overall mechanical picture.

Following concussion or other head trauma, we frequently identify areas of cranial restriction involving structures such as the sphenoid, occiput, temporal bones and facial skeleton.

These restrictions may alter the way the wider cranial system moves.

Could Cranial Rhythmic Motion Have a Pumping Function?

This is an important question.

A repeating expansion-and-relaxation cycle within a fluid-filled biological system naturally raises the possibility that the movement may contribute to fluid movement or pressure dynamics.

From a biomechanical perspective, it is reasonable to consider whether rhythmic cranial movement could have a pumping or pressure-modulating influence within the cranial environment.

This idea also has a long history within cranial osteopathic theory.

CSF movement is known to be dynamic and pulsatile, with cardiovascular pulsation, respiration, pressure gradients and other physiological forces contributing to its movement.

Our clinical model is that cranial rhythmic movement may be another mechanical component of this dynamic environment.

If cranial movement becomes restricted following trauma, we therefore consider whether that restriction may alter the normal mechanical behaviour of the cranial system.

What has not yet been established is precisely how much this palpable cranial rhythm contributes to CSF circulation, or whether changing cranial mechanics through treatment produces measurable changes in CSF or glymphatic flow.

That does not make the mechanical relationship irrelevant.

It makes it an important area for further investigation.

Two Rhythms Within One Fluid System

This gives us an interesting way of looking at the wider system.

There is a cranial rhythm described within cranial osteopathy.

There is also a powerful respiratory rhythm, generated through breathing and thoracic pressure changes, that is known to influence CSF movement.

NasalRx has potential relevance to both sides of this mechanical picture.

We often observe improved cranial and facial movement following treatment.

And we very commonly observe improved nasal airflow.

The combination of improved cranial mobility and easier nasal breathing may therefore create a more favourable mechanical and respiratory environment for the normal physiological forces involved in cerebral blood flow, venous drainage and CSF movement.

Whether these changes translate into measurable alterations in CSF flow or glymphatic clearance following NasalRx requires direct investigation.

But it provides a much richer research hypothesis than considering cranial mechanics, nasal breathing or CSF dynamics in isolation.

What Is the Glymphatic System?

The glymphatic system describes a pathway involved in fluid exchange and waste clearance within the brain.

CSF interacts with fluid surrounding brain tissue along spaces associated with blood vessels.

This exchange appears to help move metabolic waste products away from brain tissue.

Sleep is particularly important.

Glymphatic activity appears to change considerably across the sleep-wake cycle, which is one reason researchers are interested in the relationship between sleep, brain health and neurological recovery.

The brain also has meningeal lymphatic vessels associated with its surrounding membranes.

Together, glymphatic and meningeal lymphatic research has significantly changed the older idea that the brain is largely isolated from lymphatic and fluid-clearance systems.

What Happens to These Systems After Traumatic Brain Injury?

This is where the research becomes particularly relevant to concussion.

Experimental and clinical research suggests traumatic brain injury can disturb aspects of:

• cerebral blood flow
• neurovascular regulation
• CSF dynamics
• inflammatory signalling
• glymphatic function
• sleep
• metabolic waste clearance

Much of the detailed mechanistic glymphatic research has been performed in animal models, and measuring glymphatic function directly in living humans remains difficult.

There is therefore still a great deal researchers do not know.

However, there is increasing scientific interest in the possibility that altered fluid exchange and clearance form part of the complex physiological response to traumatic brain injury.

Neuroinflammation and Persistent Symptoms

Concussion can trigger an inflammatory response within the nervous system.

Research examining people with persistent post-concussion symptoms has identified changes in inflammatory signalling molecules, including findings involving CSF biomarkers.

This provides evidence that persistent symptoms can be accompanied by ongoing biological changes.

What this research does not establish is that inflammatory molecules simply become “trapped” because a cranial fixation prevents CSF from flushing them away.

The relationship is likely to be more complex.

A more useful question is whether neuroinflammation, altered fluid physiology and the physical environment surrounding these systems interact during recovery.

That remains an important area of investigation.

Why Can Brain Fog and Fatigue Persist?

Brain fog and fatigue are common complaints following concussion.

Patients may describe:

• slowed thinking
• difficulty concentrating
• reduced mental stamina
• difficulty finding words
• feeling mentally “heavy”
• becoming exhausted after relatively modest cognitive activity
• needing substantially more recovery after work, reading or screen use

These symptoms are unlikely to have one universal cause.

Post-concussion brain fog and fatigue may involve overlapping neurological, metabolic, autonomic, sleep-related and other physiological factors.

Glymphatic function, cerebral circulation and neuroinflammation are particularly interesting parts of that developing research picture.

The Dura: Where Mechanics and Physiology Meet

This is where the subject becomes especially relevant to Cranial Solutions.

The dura mater is the strong connective-tissue membrane surrounding the brain and continuing around the spinal cord.

Within the cranial cavity, it has important attachments to the skull and cranial base.

It also forms structures such as the falx cerebri and tentorium cerebelli and has close anatomical relationships with the venous sinuses.

At the cranial base, the dura relates closely to structures including the:

• sphenoid
• occiput
• temporal bones
• cranial foramina
• upper cervical and craniocervical region

We use the term dural tension or torsion as a biomechanical clinical concept when considering abnormal mechanical tension or asymmetry within this interconnected system.

The important underlying anatomy is that the dura is mechanically connected to the cranial and spinal environment.

Consequently, changes in cranial mechanics cannot be considered entirely separate from the membranes contained within that environment.

The Sphenoid, Occiput and Cranial Base

The sphenoid and occiput occupy central positions within the cranial base.

The sphenoid has extensive relationships with the facial skeleton, orbits and cranial cavity.

The occiput forms much of the posterior cranial base and articulates inferiorly with the upper cervical spine.

Together with the temporal bones, these structures create a complex mechanical environment around important neural, vascular and dural anatomy.

At Cranial Solutions, we often identify restriction or asymmetry in cranial and facial movement following head trauma.

Particular attention may be given to relationships involving the sphenoid, occiput, temporal bones, cranial base and upper cervical region.

But NasalRx is not limited to subtle movement at the sphenoid or sphenobasilar region.

The structural changes we observe can involve a much wider craniofacial system.

Structural Change and Cranial Mechanics

The changes produced with NasalRx can occur at different levels.

Some are relatively subtle changes in cranial compliance and movement.

Others are much more obvious mechanical releases.

Depending on the individual pattern of restriction, we can see and palpate changes involving structures such as the:

• vomer
• ethmoid
• sphenoid
• maxillae
• palatine bones
• zygomatic bones
• temporal bones
• occiput

During some corrections there can also be an audible cavitation or release associated with movement through these articulations.

This is important for understanding what NasalRx actually is.

NasalRx is a mechanically applied structural treatment.

Controlled pressure is introduced through the nasal passages to apply force to the internal nasal and craniofacial structures. That force can be transmitted through an interconnected system of bones, sutures, articulations and connective tissues.

Sometimes the resulting change is subtle.

At other times there is a much more substantial mechanical release, followed by an immediately apparent change in cranial or facial movement.

The cranial rhythmic motion described earlier in this article remains relevant to our broader understanding of cranial mechanics and fluid dynamics, but it is one component of a much larger structural picture.

Our primary clinical focus is the restriction itself: where it is, how the surrounding structures are moving, and what changes when that restriction is treated.

The Upper Neck and Myodural Bridge

The cranial system also connects mechanically with the cervical spine.

The myodural bridge complex provides a particularly interesting anatomical example.

Connective-tissue structures link several deep suboccipital muscles with the spinal dura around the upper cervical region.

Research has investigated the possible functional significance of these connections, including relationships with cervical movement and CSF dynamics.

For Cranial Solutions, the myodural bridge is not considered an isolated explanation for post-concussion symptoms.

It is one component of a broader occipital-cervical-dural system.

This is why cervical assessment can form an important part of our post-concussion approach.

Where NasalRx Fits Into This Structural Model

NasalRx gives us a distinctive way of accessing the craniofacial system from within the nasal passages.

Brief, controlled pressure is applied internally to influence structures that cannot be approached in the same way through external manual treatment.

Depending on the individual pattern of restriction, treatment may influence mechanical relationships involving the vomer, ethmoid, sphenoid, maxillae, palatine and zygomatic regions, with changes also observed through the temporal, occipital and wider cranial system.

Clinically, we often observe changes in:

• movement of specific cranial and facial structures
• symmetry and mobility through the craniofacial system
• sphenoid and cranial-base mechanics
• occipital and posterior cranial movement
• facial and scalp tension
• nasal airway space and airflow

Patients may simultaneously report changes in:

• head pressure
• headache
• brain fog or mental clarity
• light sensitivity
• discomfort or restriction with directional eye movement
• cranial or facial tension
• posterior scalp or base-of-skull tension
• nasal breathing

This is central to the Cranial Solutions approach:

Identify the restriction. Apply a controlled mechanical force. Improve structural movement. Reassess the patient and their symptoms.

Does NasalRx Improve CSF or Glymphatic Flow?

This is the larger scientific question.

At present, we cannot say that NasalRx has been demonstrated through direct physiological measurement to increase CSF circulation or glymphatic clearance in humans following concussion.

Those effects need to be investigated directly.

What we can say is that:

1. CSF, cerebral blood flow, venous drainage, lymphatic pathways and glymphatic function form part of the brain's dynamic physiological environment.

2. Traumatic brain injury can disturb aspects of that environment.

3. Respiration is a recognised contributor to CSF movement and craniospinal pressure dynamics.

4. The dura, cranial base, blood vessels, upper cervical region and craniofacial structures form part of the physical anatomical environment in which these systems operate.

5. Cranial osteopathy has long recognised a rhythmic cranial mechanism and proposed that this movement is functionally related to CSF and fluid dynamics.

6. NasalRx can produce mechanical changes within the nasal, craniofacial and wider cranial system.

7. NasalRx often produces substantial improvements in nasal airflow, potentially making nasal breathing easier and influencing the respiratory mechanics that contribute to craniospinal pressure changes.

8. We frequently observe changes in symptoms alongside these structural changes.

The next scientific question is whether these mechanical and respiratory changes can be shown to produce measurable changes in cerebral blood flow, venous drainage, CSF dynamics, lymphatic drainage or glymphatic function.

We believe that is an important area for future research.

Why This Matters to Cranial Solutions

Our clinical model is straightforward.

A concussion exposes the head, face and neck to significant mechanical forces.

Those forces can be followed by persistent changes in cranial, facial and cervical mechanics.

The brain is simultaneously recovering within a dynamic environment involving blood flow, venous drainage, CSF, lymphatic pathways, inflammatory signalling and glymphatic function.

Respiration adds another important component because every breath produces pressure changes extending through the thorax, venous system and craniospinal fluid environment.

Cranial Solutions works specifically with the mechanical side of this interconnected system.

NasalRx gives us a distinctive method of applying a structural intervention internally through the nasal passages while frequently producing substantial improvements in nasal airflow.

Cervical treatment allows us to address relevant neck and craniocervical restriction where required.

We identify the mechanical restrictions.

We treat those restrictions.

We assess the resulting changes in cranial, facial and cervical movement.

And we monitor whether those changes correspond with meaningful improvements in the patient's symptoms and function.

That is where established anatomy and physiology, structural biomechanics, cranial osteopathic principles, emerging neuroscience and repeated clinical observation meet.

Frequently Asked Questions

Does concussion affect cerebrospinal fluid?

Traumatic brain injury research suggests that aspects of CSF physiology and fluid dynamics can be altered following injury. The extent and clinical significance of these changes in mild traumatic brain injury remain active areas of research.

Does concussion affect the glymphatic system?

Experimental research suggests traumatic brain injury can disturb glymphatic function. Human concussion research is developing, and direct measurement remains challenging.

Does brain fog mean my glymphatic system is blocked?

Not necessarily. Brain fog following concussion can have multiple contributors. Glymphatic function, cerebral circulation, sleep and neuroinflammation are all interesting areas of research, but brain fog alone does not tell us which mechanisms are involved.

Is there really a rhythm or pulse within the cranium?

Cranial osteopathy has described a rhythmic cranial movement for many decades as part of the primary respiratory mechanism.

At Cranial Solutions, we consider this rhythm relevant to the wider biomechanical model, particularly because of the longstanding proposed relationship between cranial movement and fluid dynamics.

Could the cranial rhythm help move fluid?

Cranial osteopathic theory has long proposed a relationship between cranial rhythmic motion and CSF dynamics.

Because CSF movement is pulsatile and the cranial system exhibits cyclical mechanical behaviour clinically, we consider a possible pumping or pressure-modulating relationship to be biomechanically relevant.

Exactly how much cranial rhythmic motion contributes to CSF movement has not yet been established through direct physiological measurement.

Does breathing affect CSF flow?

Yes. Respiration is one of the recognised contributors to CSF movement.

Changes in thoracic pressure during breathing influence venous and craniospinal pressure relationships, creating rhythmic changes in CSF movement.

Why might nasal breathing matter?

Nasal and mouth breathing involve different airflow resistance and can be associated with different respiratory mechanics.

This is particularly interesting to us because improved nasal airflow is one of the most consistent changes we observe following NasalRx.

If easier nasal breathing allows more effective respiratory mechanics, this may also influence the thoracic pressure changes that contribute to normal craniospinal fluid movement.

Are the changes produced by NasalRx always subtle?

No.

Some changes in cranial movement and compliance can be subtle, but NasalRx can also produce much more obvious structural releases.

Depending on the restriction being treated, we may observe significant changes through the nasal and craniofacial structures, and an audible cavitation or release may sometimes accompany the correction.

Is NasalRx an energy-based cranial technique?

No.

NasalRx is a physical, mechanically applied structural treatment.

Controlled pressure is introduced through the nasal passages to influence restricted nasal and craniofacial structures and their wider mechanical relationships.

The treatment is based on anatomy, mechanical restriction, controlled force, structural movement and clinical reassessment.

Can cranial restriction affect CSF flow?

Cranial Solutions considers this a plausible biomechanical relationship worthy of investigation, particularly where significant restriction is present following trauma.

However, identifying a mechanical cranial restriction does not by itself demonstrate impaired CSF circulation.

Does NasalRx restore CSF flow?

NasalRx is designed to influence mechanical restriction and movement within the nasal, craniofacial and wider cranial system and frequently produces noticeable improvements in nasal airflow.

Whether these structural and respiratory changes directly alter CSF circulation or glymphatic clearance requires physiological measurement and further research.

Explore the Cranial Solutions Approach

If you are experiencing persistent symptoms following concussion, our assessment looks at mechanical components that may still be relevant — including the cervical spine, cranial and facial structures, internal nasal restriction, nasal airflow and breathing pattern.