Exploring the Forces that Alter the Fluid Rhythm and Tides of the Craniosacral System

The cranial fluid system is a powerful, self-organising, homeostatic system inherent in all of us. Its therapeutic use was pioneered in the early twentieth century by osteopath Dr William Garner Sutherland DO.

History: An Anatomical Insight Becomes a Lifelong Study

Sutherland first glimpsed the skull’s capacity for motion when he observed the squamosal articulation of the temporal bone in a dried specimen. It struck him that its form resembled fish gills — an insight that led to his hypothesis that these bones were designed for movement or breathing. Over years of rigorous exploration, he postulated that the skull’s sutures permitted minute motion throughout life.

Focusing on the internal architecture of the brain — particularly the sickle-shaped membranes known as the falx cerebri, falx cerebelli, and tentorium — Sutherland identified a mechanism he termed the reciprocal tension membrane (RTM). He theorised that these inelastic structures suspended the brain and governed minute cranial movements via intrinsic tensions responsive to shape changes, initiated by the dynamic movement of cerebrospinal fluid (CSF).

Ventricular Motility and the Birth of a Therapeutic Model

Sutherland posited that the brain itself had an inherent rhythmic motility, governed by the cyclical filling and partial emptying of the cerebrospinal fluid (CSF)- filled ventricles. Through personal experimentation and self-palpation — including the use of restrictive headbands — he traced the relationship between cranial dynamics and systemic health. He concluded that small bony shifts in the cranium affected the fascia, musculature, and autonomic systems throughout the body, confirming his mentor A.T. Still’s premise: structure governs function.

Mapping Vectors and Fulcrum: An Engineering Approach

Sutherland constructed a biomechanical model of the cranium, identifying the vectors, fulcra, and tissue relationships underlying cranial motion. He understood that trauma or external forces could impose pathological fulcra, distorting the natural cranial rhythm. His solution: a therapeutic return to balance through palpation and facilitation of a “still point” — a moment of profound quiet in which the system resets.

This still point is a phase of complete cessation — no movement, no pulse, only balance—enabling the tissues to unwind from held tensions and re-enter their physiological pattern.

Cranial Osteopathy: Mechanism Meets Mystery

In 1955, Sutherland introduced his findings to the osteopathic field. His ideas, initially dismissed by more mechanistic colleagues, gave rise to two broad schools:

• Mechanical cranial osteopathy: emphasising structural correction
• Energetic cranial osteopathy: working with fluid tides and systemic rhythms

Both approaches aim to restore health by aligning the body with its primary organising rhythm — the movement of CSF.

Structure, Function, and the Primary Tide

Disruptions in cranial structures alter physiological function, impacting gait, mood, and systemic coherence. Cranial work posits that trauma disrupts the rhythm of CSF at cellular, tissue, and organ levels. The inherent rhythmic filling and emptying of the ventricles generates subtle motion throughout the brain axis, affecting dural membranes and cranial bones. These rhythmic pulses — often averaging a six-second cycle — reflect overall health.

However, not all disruptions are physical. Sutherland’s engineering model lacks an ontological dimension — an understanding of the unseen forces that organise, distort, or reorient our being. Here lies the limitation of the purely structural model.

‘Thinking, Feeling, Knowing Fingers’: Palpation as Perception

Effective palpation is both technical and intuitive. It requires anatomical knowledge, but also attunement — the ability to perceive the nuances of movement and stillness. Some models move beyond anatomy to embrace energetic sensing. But all are coloured by the practitioner’s limbic history and unconscious biases. Our interpretation of what we feel is shaped by who we are.

Gestures as Protolanguage

Gesture — from animal signalling to ritual mudras — may act as a bridge between internal states and outer expression. In Indian traditions, mudras are used to influence internal states via the somatosensory cortex. When combined with ontological kinesiology, these gestures help construct a nonverbal narrative from the body’s own language, allowing access to unconscious processes.

Craniosacral Therapy and the Still Point

Craniosacral therapy adopts Sutherland’s core idea: facilitating stillness to restore rhythmic balance. While many practitioners attune to a single rhythm (e.g. the cranial rhythmic impulse), deeper healing often involves tuning into a spectrum of rhythms — including the subtle waves below the CRI, such as the Traube-Hering wave.

Ontological Cranial Work

InnerDialogue and Ontological Kinesiology refine cranial work further. Rather than manipulating structures, the practitioner listens to the client’s core narrative through mudras and muscle testing. The client’s body indicates the story that wants to be told. By holding the shape and essence of that story, the practitioner facilitates a return to physiological and spiritual coherence.

The Role of Companioning

Change occurs not by imposition, but through witnessing. The practitioner becomes a companion, holding the person in their narrative without judgement. Healing arises when the narrative is met with awareness, stillness, and human presence.

Solihin Thom, DO (UK), DAc (SL) is the author of Being Human: Exploring the Forces that Shape Us and Awaken Inner Life. He has taught Cranial Fluid Dynamics® in Russia, Europe, the UK, and the US for over 37 years. His work emphasises the cranial fluid system as a vehicle for therapeutic transformation and inner coherence.