Biodynamic Craniosacral Therapy (BCST) has gained recognition as a powerful, gentle approach to healing and wellness. Perhaps you’ve already experienced BCST, or you’ve heard positive recommendations from friends or professionals. But for many, the workings of BCST are somewhat mysterious.

In this article, we'll delve into the underlying processes unfolding during a BCST session, exploring how this subtle yet potent modality works with our body's innate intelligence to promote healing and balance.

Although the experience of BCST can be appreciated without a technical understanding of what’s happening, having some level of knowledge of the many processes at play can enhance your experience on the table and the benefits that you receive.

This does not mean that you need to be trying to keep all of this in mind while you are receiving BCST. Take in the information that follows, let it soak in, and let it go, trusting that it has made its impression on you.

The craniosacral system: The foundation of BCST

At the heart of BCST lies the craniosacral system, a fundamental yet often overlooked aspect of our physiology.

This system comprises the membranes and fluid that surround and protect the brain and spinal cord, extending from the bones of the skull, face, and mouth (which make up the cranium) down to the sacrum, or tailbone area.

Central to the craniosacral system is the cerebrospinal fluid (CSF), a clear, colourless fluid that circulates around the brain and spinal cord.

This fluid helps maintain the optimal environment for our central nervous system, providing nutrients, removing waste products, and cushioning the brain and spinal cord from physical shocks.

The CSF is a highly refined filtrate of the blood plasma; thus, we can think about CSF as continuous with the entire circulatory system, but playing a special role in surrounding and nourishing our precious brain.

Craniosacral therapists pay a good deal of attention to the craniosacral rhythm, or cranial rhythmic impulse. This subtle, rhythmic movement is believed to be created by the production and reabsorption of cerebrospinal fluid, creating a tide-like motion that can be felt throughout the body.

BCST practitioners are trained to sense this rhythm, using it as a diagnostic tool and a means of facilitating healing.

The importance of the craniosacral system extends far beyond its immediate anatomical boundaries. Through its intimate connection with the central nervous system, it influences every other system in the body. The state of the craniosacral system can affect our overall health, impacting everything from our stress levels and emotional well-being to our immune function and physical vitality.

BCST works by supporting the body’s inherent healing mechanisms, many of which are closely tied to the craniosacral system. By gently interacting with this system, practitioners can facilitate a cascade of positive effects throughout the body. This approach works by aligning with the body’s natural capacity for healing, supporting rather than forcing change, with the assumption that the vitality of the body will move us towards states of greater well-being when provided with a favourable environment for healing to occur.

As we explore the specific mechanisms of BCST in the following sections, keep in mind that all of these processes are interconnected, much like the craniosacral system itself is connected to every other system in the body. We will focus on different body systems sequentially, but allow your imagination to make connections between all these layers of explanation to grasp the holistic picture.

Key Mechanisms of BCST

Physical Structure and Fluid Dynamics

One of the primary mechanisms through which BCST operates is its influence on physical structure and fluid dynamics within the body. This starts with the regulation of the craniosacral rhythm. Through gentle touch and focused attention, practitioners can help optimize the flow of cerebrospinal fluid, promoting a balanced and healthy rhythm. This balanced rhythm supports overall health and vitality, influencing everything from brain function to emotional well-being. The craniosacral rhythm typically oscillates at a rate of 6-12 cycles per minute, distinct from both the cardiac and respiratory rhythms, and practitioners learn to sense its quality, amplitude, and symmetry.

BCST works extensively with the fascia, the connective tissue that surrounds and interpenetrates every structure in our body. This fascial network is far more sophisticated than once believed: it's now understood to be a continuous, three-dimensional web that extends from the surface of the skin to the nucleus of every cell! Restrictions in the fascia can cause pain, limit mobility, and even affect organ function. These restrictions often develop as a protective response to physical or emotional trauma, chronic stress, or inflammation.

Through subtle touch, BCST can help release these fascial restrictions. Release does not happen through force or direct pressure; instead, practitioners create a supportive context that allows the fascia to release itself. This process often involves what's called “unwinding,” where tissues move in specific patterns as they release stored tension. This unwinding can occur locally in a specific area or globally throughout the body, leading to improved mobility, reduced pain, and better overall function.

The fascial system is also intimately connected with the body’s fluid systems. Recent research has revealed that fascia contains microscopic fluid-filled channels called “prelymphatic pathways” that play a crucial role in fluid circulation and immune function. BCST’s effect on fascia, therefore, has direct implications for fluid dynamics throughout the body.

Structural alignment is another key aspect of BCST’s physical effects. The therapy gently encourages proper alignment of the skull, spine, and pelvis. This process often begins at the level of the cranial bones, which, contrary to traditional medical understanding, maintain a small degree of motion at their sutures throughout life. This subtle mobility is essential for the proper flow of cerebrospinal fluid and the functioning of the central nervous system. As an example of the relationship between structure and fluid dynamics, restrictions in the tentorium cerebelli (a layer of dura mater that separates the cerebellum from the cerebral hemispheres) can affect not only structural alignment but also the flow of cerebrospinal fluid and the function of nearby venous sinuses.

Beyond its influence on cerebrospinal fluid, BCST has profound effects on overall fluid dynamics. The therapy can improve the circulation of blood and lymph through several mechanisms. First, by promoting parasympathetic nervous system activity, it helps optimize blood vessel tone. Second, by releasing fascial restrictions, it removes impediments to fluid flow. Third, by supporting proper structural alignment, it helps maintain the pressure gradients necessary for optimal fluid circulation.

This optimization of fluid dynamics enhances cellular nutrition and waste removal, supporting the health of every tissue in the body. It's particularly beneficial for the lymphatic system, gently encouraging lymph flow and supporting the body's detoxification processes and immune function. Although people do not always think about circulation in these terms, proper fluid flow is essential for delivering nutrients, removing waste products, maintaining proper pH balance, and supporting immune system function. A Chinese saying states: “If there is no free flow, there is pain; if there is free flow, there is no pain” (不通這痛, 痛則不通). Tissue health is inextricably linked to fluid exchange.

Nervous System Regulation

Perhaps one of the most immediately apparent mechanisms of BCST is its ability to regulate the nervous system. This regulation begins with the central nervous system—the brain and spinal cord—and has a global effect on the body and mind. Understanding this mechanism requires appreciating the intricate relationship between the nervous system and the craniosacral system.

The dural tube, which contains and protects the spinal cord, is continuous with the dural membranes surrounding the brain. This creates a direct mechanical link between craniosacral motion and the environment of the central nervous system. As ‘virtual’ as the thought processes generated by the brain may seem, it is striking how the brain’s functioning is dependent on physical influences such as the health of its tissues and the appropriate level of pressure and movement from the surrounding structures.

One of the most immediate effects of BCST is its ability to promote parasympathetic nervous system activation, often referred to as the “rest and digest” state. This state is essential for healing, regeneration, and recovery from stress. During a BCST session, many clients experience a profound shift from sympathetic dominance (the “fight or flight” state that many of us live in) to parasympathetic activation. This shift manifests in numerous ways, such as:

Decreased heart rate and blood pressure
Improved digestion and gut motility
Enhanced immune system function
Reduced muscle tension
Improved sleep quality
Decreased anxiety and stress hormones
Enhanced tissue repair and healing

Beyond these immediate effects, BCST has a broader influence on the autonomic nervous system by promoting changes in one’s mood and overall perception of reality. The autonomic nervous system, which controls many of our involuntary bodily functions, operates optimally when it can smoothly transition between sympathetic and parasympathetic states according to the demands of the situation. Through regular BCST sessions, many clients report improved autonomic flexibility—the ability to respond appropriately to stress while maintaining the capacity to return to a calm state when the stress subsides.

The vagus nerve plays a central role in this regulatory process. As the primary nerve of the parasympathetic nervous system, the vagus nerve influences nearly every major organ system in the body. BCST can affect vagal tone through several mechanisms:

Direct mechanical influence through holds that access the exits of the cranial nerves, including the vagus nerve;
Indirect stimulation through touch and attention to specific areas that are enervated by the vagus nerve; and
Creation of a safe, regulated environment that supports healthy vagal function.

Recent research in polyvagal theory helps explain why the gentle, non-threatening touch of BCST can be so effective. According to this theory, our nervous system is constantly evaluating environmental safety; this unconscious scanning is called neuroception. The predictable, gentle nature of BCST helps create a sense of safety that allows the nervous system to shift into a state of calm and restoration. We are social creatures, and in our evolutionary history, closeness with other supportive humans (being with one’s tribe) represented a kind of safety that could not be attained alone. Despite the many differences between modern life and earlier eras, the same holds true today. Being in the presence of grounded and predictable others relaxes the nervous system in an irreplaceable way.

Brain wave patterns also show interesting changes during BCST sessions. Many clients enter a state characterized by increased alpha and theta waves, similar to what is seen in deep meditation. This state is associated with the following: enhanced creativity and problem-solving; improved memory consolidation; reduced anxiety and depression; increased learning capacity; better emotional regulation; and enhanced immune function.

These changes in brain wave patterns may help explain why many clients report insights, emotional releases, or a sense of clarity during or after sessions. The shift into these slower brain wave patterns also supports the body’s natural healing mechanisms by reducing stress hormones and promoting the production of growth and repair hormones.

Furthermore, BCST can influence the glymphatic system. Recently discovered, the glymphatic system is the brain's lymph-like waste clearance system that operates primarily during states of deep rest. By promoting these restful states, BCST is thought to support the brain's natural detoxification processes, contributing to improved cognitive function and neurological health.

Sensory Integration and Body Awareness

BCST plays a significant role in enhancing sensory integration—the sophisticated process by which our nervous system receives, organizes, and interprets sensory information. This aspect of BCST works on multiple levels, influencing both our external senses (exteroception) and our internal sensing systems (interoception and proprioception).

Therapeutic touch in BCST has unique qualities that make it particularly effective for sensory integration. In our everyday lives, when we experience physical touch, whether welcome or unwelcome, there is generally some expectation of a response from us in return. By contrast, BCST touch is non-directive and without agenda. Rarely in life do we have an opportunity to be with another nervous system without having to scan our environment, monitor for safety, read social cues, and be primed to respond appropriately. This being-together while being at rest allows the nervous system to process sensory stimuli without becoming overwhelmed. The practitioner's touch provides a consistent, reliable reference point that helps the nervous system calibrate its responses to sensory input.

For individuals with sensory processing challenges, this work can be extremely useful. Common signs of sensory processing difficulties include issues discriminating between different sensory inputs, poor balance or spatial awareness, and difficulty maintaining an appropriate activity level. Individuals often experience oversensitivity to touch, sound, or movement; chronic hyperstimulation can contribute to emotional reactivity to sensory experiences.

BCST can help address these challenges by:

Providing a safe environment for the nervous system to process sensory information
Supporting the development of more refined sensory discrimination
Helping integrate primitive reflexes that may be interfering with sensory processing
Calming an overactive stress response that can interfere with sensory integration

The enhancement of interoception—our ability to sense our internal state—is a key mechanism of BCST. Interoception is the sense that tells us whether we are hot or cold, hungry or full; it includes the sensations of our heart rate, breathing, muscle tension, and pain. Importantly, interoception is also key to our experience of emotional states. It is by detecting the physical sensations of our body that we draw conclusions about how we feel emotionally.

Through the quiet, focused nature of craniosacral sessions, clients often become more attuned to their internal sensations. This increased interoceptive awareness has far-reaching implications for health and well-being. Research has shown that accurate interoception is linked to better emotional regulation, more effective stress management and pain management, enhanced immune function, and improved mental health overall. As the saying says: “Feel it to heal it.”

Proprioception—our sense of the position and movement of our body parts—also improves through BCST. Proprioception is enhanced in craniosacral therapy partly through peripheral physical changes, such as the release of restrictions that may be interfering with proper proprioceptive feedback and improved function of the receptors in joints and muscles that provide positional information. It also occurs through neural changes, such as better integration of proprioceptive information in the central nervous system and enhanced awareness of subtle movement patterns.

As restrictions in the body are released and alignment improves, many people report a greater sense of ease in their body and improved coordination. They may enjoy improved athletic performance and greater confidence in the way that they physically move through the world.

BCST cultivates a deeper level of body awareness that goes beyond simple sensation. The quiet, reflective nature of BCST sessions creates an opportunity for clients to develop embodied presence—a state of being fully awake to and aware of their bodily experience. This kind of self-awareness a powerful tool for ongoing self-regulation, allowing a person to recognize and respond to stress earlier, tend to their health, understand the connection between physical and emotional states, and set appropriate boundaries. It is also an intrinsically pleasurable state, and affords a sense of peace and contentment that cannot be acquired through external means.

These improvements in sensory integration, interoception, proprioception, and body awareness provide clients with a greater capacity for resilience in daily life, as well as helping create a new baseline of embodied awareness with a multitude of benefits for long-term health and enjoyment.

Emotional and Memory Processing

An important cross-over between BCST and somatic therapy is its potential to facilitate emotional processing and the release of stored trauma along with tension from the body. This mechanism is rooted in the understanding that our bodies physically remember emotional experiences and trauma, a concept increasingly supported by research in neuroscience and psychophysiology.

There is an intimate relationship between physical and emotional holding patterns in the body. When we experience stress, trauma, or strong emotions, our bodies physically respond like any animal would under threat. Muscles tense, we take on a defensive posture, and breathing patterns quickens; our movements patterns change; our nervous system shifts into a different gear. Over time and through repeated activation, these responses can become habitual, creating what we might call “body memory.”

BCST creates a safe container for these stored emotions and memories to emerge and be processed. This doesn't necessarily mean reliving traumatic experiences—in fact, staying in the present moment and listening to the unfolding story that the body is telling right now is generally what’s encouraged in a craniosacral session. BCST supports processing without retraumatization according to these principles:

Titration: The gradual release of stored tension allows the nervous system to process manageable amounts of activation
Pendulation: The natural oscillation between activation and settling helps prevent overwhelm
Recognition of resources: Clients connect with their inner resources – for example, the sense of being at home in their body, in a pleasurable and expansive state of awareness – and build trust in their capacity for regulation
Present-moment awareness: The focus on current physical sensations, whether pleasant or unpleasant, can be grounding and reassuring, and helps prevent dissociation
Co-regulation: The practitioner's regulated nervous system offers alternative patterns and rhythms for the client’s nervous system to entrain with

Some researchers theorize that BCST can access and release stored information (i.e. memory) on a cellular level. This may occur through several mechanisms: changes in cell membrane tension and permeability; alterations in neuropeptide receptor expression (chemical messengers of the brain); modifications in gene expression; changes in cellular metabolic processes; and shifts in cellular electric potential. Although the exact mechanism of this cellular memory release is not fully understood, this is an area of interest that we may learn more about in the future.

Energetic and Bioelectric Aspects

Throughout its history, craniosacral therapy has straddled the boundary between biomechanical therapeutic approaches and more esoteric forms of healing that attend to subtle energies. These forms of influence, while sometimes challenging to measure with conventional instruments, are increasingly addressed by emerging research in biophysics and energy medicine.

The bioelectric aspects of BCST can be understood through several key concepts:

Cellular Electrical Activity: Every cell in our body maintains an electrical potential across its membrane. This potential is crucial for cellular function and communication. Changes in cellular electrical activity can influence protein synthesis, ion transport, cell division, tissue repair, and inflammatory responses.
Tissue Piezoelectric Effects: Connective tissues, especially bone and fascia, generate electrical charges when compressed or stretched. These piezoelectric charges have effects on cell behaviour, tissue repair, local circulation, and neural activity.
Bioelectric Fields: The collective electrical activity of cells creates measurable bioelectric fields. These fields play roles in tissue organization, wound healing, development and regeneration, cell-to-cell communication, and nervous system function.

BCST practitioners often report sensing these bioelectric phenomena as subtle pulsations, a sense of electrical charge in the tissues, a directional magnetic pull, or shifts in local energy fields.

The energetic aspects of craniosacral therapy extend beyond purely bioelectric phenomena. In BCST language, we often use the concept of the field: the energy body that surrounds a living thing, which is perceptible when we practice attuning to it. The field has an optimal organization, but can be organized in less or more coherent ways, depending on the condition of the person’s health. Biodynamic work can facilitate reorganizations in the energy field.

The practitioner’s and client’s fields interact during a table session, and a combined relational field is created. Through the phenomenon of resonance, different energies that come into contact can harmonize and synchronize. We see this occurring with brain waves when people interact, as well as with heart rate coherence when people are engaged in the same task or listening to the same story. On many levels, our biological rhythms become entrained and physiological processes synchronize when we are feeling connected with one another. This phenomenon has therapeutic relevance, where a dysregulated system can ‘learn’ from a regulated system and (re)establish energetic harmony and balance.

BCST pays attention to the flow of energy throughout the body, identifying areas of blocked or restricted energy flow and providing support for optimal energy distribution throughout the system. With its focus on resolving inertial fulcrums (points of tension and holding in the body that develop due to the stresses of lived experience), craniosacral therapy recognizing that the energy of the body can be ‘bound up’ in maintaining physical and emotional patterns that do not serve overall health. By instigating reorganization of these patterns, the stuck energy is available to flow through the entire system, contributing to an increased sense of vitality.

Systemic Effects

We have already discussed multiple body systems and the ways that they are influenced by craniosacral touch. To bring all of this information together, let us name and elaborate on the systemic effects that represent the influence of BCST on overall health and wellness.

Enhanced Self-Healing Mechanisms: BCST can help to optimize immune system function (e.g. regulating inflammation), enhance tissue repair processes (e.g. cellular regeneration), and increase metabolic efficiency (e.g. nutrient utilization, waste elimination and energy production).
Hormonal Balance Support: BCST can influence the functioning of the endocrine system (e.g. improving hypothalamic-pituitary axis function). It can have have specific hormonal effects, including reducing stress hormone levels, improving thyroid function, balancing the reproductive hormones, and increasing growth hormone production.
Improved Circulation and Metabolism: Through its focus on fluids, BCST can enhance blood flow, improve organ perfusion, and enhance tissue oxygenation. The lymphatic system also benefits from increased circumation, which bolsters the immune system, enhances detoxification, and reduces edema and inflammation.
Enhanced Autonomic Balance: On an experiential level, we can easily appreciate BCST’s effects on the autonomic nervous system. Stress response regulation, improved sleep patterns, and enhanced digestive function are all tangible changes that we can notice.
Tissue Health and Repair: With its promotion of free flow of energy and fluids, as well as its impact on cellular metabolism, BCST can have positive effects on tissue health, such as through hydration and waste removal from tissues.

Craniosacral therapy is a deeply holistic, integrative therapy. From its effects on physical structure and fluid dynamics to its influence on our nervous system, sensory integration, and emotional processing, BCST works on multiple levels to promote balance and healing. As research in this field continues to evolve, our understanding of these mechanisms will undoubtedly deepen. Whether you're a seasoned BCST enthusiast or just beginning to explore its potential, may this discussion enrich your appreciation of craniosacral therapy and your journey towards health and well-being.

So how does craniosacral therapy work?