Craniosacral therapy
Craniosacral therapy (also called CST, cranial osteopathy, also spelled CranioSacral bodywork or therapy) is a method of Complementary and alternative medicine used by massage therapists, naturopaths, chiropractors, osteopaths, physical therapists, nurses, dentists, and doctors who manually apply a subtle movement of the spinal and cranial bones to bring the central nervous system into harmony. This therapy involves assessing and addressing the movement of the cerebrospinal fluid (CSF), which can be restricted by trauma to the body, such as through falls, accidents, and general nervous tension. By gently working with the spine, the skull and its cranial sutures, diaphragms, and fascia, the restrictions of nerve passages are eased, the movement of CSF through the spinal cord can be optimized, and misaligned bones can be restored to their proper position.  This therapy is said to be particularly useful for mental stress, neck and back pain, migraines, TMJ Syndrome, and for chronic pain conditions such as fibromyalgia.

# History
Cranial Osteopathy was originated by physician William Sutherland, D.O. (1873-1954), who studied under the founder of osteopathy, Andrew Taylor Still, at the first American School of Osteopathy (now Kirksville College of Osteopathic Medicine) in 1898-1900. While looking at a disarticulated skull, Sutherland was struck by the idea that the cranial sutures of the temporal bones where they meet the parietal bones were "beveled, like the gills of a fish, indicating articular mobility for a respiratory mechanism."
The idea that the bones of the skull could move was contrary to contemporary anatomical belief. Sutherland spent many years attempting to disprove his theory, but research on himself and on his patients led him to conclude that the bones of the skull do move along their sutures, and any hindrance in movement may be associated with a dysfunction.
After confirming the presence of movement between the bones of the skull, Sutherland evolved the idea that the dural membranes act as 'guy-wires' for the movement of the cranial bones, holding tension for the opposite motion. He used the term reciprocal tension membrane system (RTM) to describe the three Cartesian axes held in reciprocal tension, or tensegrity, creating the cyclic movement of inhalation and exhalation of the cranium. He called this breathing movement the primary respiratory mechanism, and later described its origin as the Breath of Life,
from the Book of Genesis (2:7). This was an acknowledgement of the vital force as a fundamental aspect of osteopathic philosophy.
The RTM as described by Sutherland includes the spinal dura, with an attachment to the sacrum. In his observation of the cranial mechanism, Sutherland found that the sacrum moves synchronously with the cranial bones. The mechanical relationship between motion in the sacrum and the parietal bones has since been confirmed in experiments using electrodes measuring capacitance across parietal sutures of the squirrel monkey.
Sutherland began to teach this work to other osteopaths from about the 1930s, and tirelessly continued to do so until his death. His work was at first largely rejected by the mainstream osteopathic profession as it challenged some of the closely held beliefs among practitioners of the time. However, his clinical results were said to be impressive and he began to attract a small group of osteopaths who  studied with him.
In the 1940s the American School of Osteopathy started a post-graduate course called 'Osteopathy in the Cranial Field' directed by Sutherland, and was followed by other schools. This new branch of practice became known as "cranial osteopathy". As knowledge of this form of treatment began to spread, Sutherland trained more teachers to meet the demand, notably Drs Viola Frymann, Edna Lay, Howard Lippincott, Anne Wales, Chester Handy and Rollin Becker.
The Cranial Academy was established in the US in 1947, and continues to teach DOs, MDs, and Dentists "an expansion of the general principles of osteopathy"
including a special understanding of the central nervous system and primary respiration.
Towards the end of his life Sutherland began to sense a "power" which generated corrections from inside his clients' bodies without the influence of external forces applied by him as the therapist.  Similar to Qi and Prana, this contact with the Breath of Life changed his entire treatment focus to one of spiritual reverence and subtle touch. 
This spiritual approach to the work has come to be known as both 'biodynamic' craniosacral therapy and 'biodynamic' osteopathy, and has had further contributions from practitioners such as Becker and James Jealous (biodynamic osteopathy), and Franklyn Sills (biodynamic craniosacral therapy). The biodynamic approach recognises that embryological forces direct the embryonic cells to create the shape of the body, and places importance on recognition of these formative patterns for maximum therapeutic benefit, as this enhances the ability of the patient to access their health as an expression of the original intention of their existence.
In 1953 Sutherland established the Sutherland Cranial Teaching Foundation as a way of providing a continuity for his teaching.
From 1975 to 1983, osteopathic physician John E. Upledger neurophysiologist and histologist Ernest W. Retzlaff worked at Michigan State University as a clinical researchers and professors. They set up a team of anatomists, physiologists, biophysicists, and bioengineers to investigate the pulse he had observed and study further Sutherland's theory of cranial bone movement. Upledger and Retzlaff went on to publish their results, which showed support for both the concept of cranial bone movement and the concept of a cranial rhythm.
Upledger developed his own treatment style, and when he started to teach his work to a group of students who were not osteopaths he generated the term 'CranioSacral therapy', based on the corresponding movement between cranium and sacrum. Craniosacral therapists often (although not exclusively) work more directly with the emotional and psychological aspects of the patient than osteopaths working in the cranial field. The Upledger Institute, formed in 1987, has many international affiliates
united by Upledger's International Association of Healthcare Practitioners.
The Craniosacral Therapy Association of the UK (CSTA) was established in1989 to promote and regulate craniosacral therapists from various UK colleges.
Graduates from the College of Craniosacral Therapy who had their own register later became eligible for registration with the CSTA. The Craniosacral Therapy Association of North America was founded in 1998 for the recognition, registration, and as a referral service for certified Craniosacral Therapists and students.
The Craniosacral Therapy Association of Australia was established in 2004.

# The Primary Respiratory Mechanism
Craniosacral therapy is originally based on Sutherland's 'Cranial Concept',
which proposed a system known as the Primary Respiratory Mechanism (PRM). The basis of PRM function has been summarised in the following five phenomena:
- Inherent motility of the central nervous system
- Fluctuation of the cerebrospinal fluid
- Mobility of the intracranial and intraspinal dural membranes
- Mobility of the cranial bones
- Mobility of the sacrum between the ilia
The effect of the above five on the rest of the body is suggested by Magoun
as a sixth phenomenon.

## Inherent motility of the central nervous system
Still described the inherent motion of the brain as a "dynamo," beginning with the cerebellum,
a century before electroencephalography (EEG) studies confirmed the presence of this activity.
Emanuel Swedenborg was the first to discover inherent motion in the brains of living dogs in the 18th Century. His work has since been verified by human physiologists: according to modern radiological observations the pulsatility of the central nervous system (CNS) is a function of the cardiac cycle, as described by Bergstrand in 1985 using magnetic resonance imaging.
The intracranial fluid fluctuation can be seen as an interaction between four main components: arterial blood, capillary blood (brain volume), venous blood and cerebrospinal fluid (CSF).
The function of such a mechanism is explained by Lee
as being based on a fulcrum created by the root of the cerebellum and its hemispheres moving in opposite directions, resulting in an increase in pressure which squeezes the third ventricle. The pulsation is described as essentially a recurrent expression of the embryological development of the brain.
The amplitude and phase of theta rhythms in the cortex of the human brain have been studied using magnetic resonance imaging. High gamma activity has been found to reflect the activation of a local cortical area and is correlated with the blood oxygen level dependent MRI-signal. The much slower theta rhythm is more distributed across the cortex and is associated with novelty, attention, working memory, and exploratory behavior. The strength of the theta-gamma coupling is correlated with variations in a range of cognitive tasks. 
This suggests a significant physiological role in CNS rhythmical movement.
The motility of the CNS in turn causes a rhythmic fluctuation of the CSF.

## Fluctuation of the cerebrospinal fluid
Sutherland used the term "Tide" to describe the inherent fluctuation of fluids in the Primary Respiratory Mechanism. Tide alludes to the concept of ebbing and flowing, but also the contrast between waves on the shore having one rhythm, with the longer rate of lunar tides below. The Tide incorporates not only fluctuation of the CSF, but of a slow oscillation in all the tissues of the body, including the skull.
Practitioners work with cycles of various rates:
- 10-14 cycles per minute - the original "Cranial Rhythmic Impulse" (CRI) (also described as 6-14 times per minute)
- 2-3 cycles per minute - the "mid-Tide"
- 6 cycles every 10 minutes - the "long Tide"
Following on from the work of Swedenborg, Traube and Hering in the 19th Century observed fluctuations in the arterial rates of dogs (the Traube-Hering wave) at similar rates to those reported by cranial practitioners. In 1960 Lundberg made a continuous recording of intracranial activities of traumatised patients, finding three waves, one of which resembles the CRI.
Research has not verified a large correlation in rates detected between examiners working simultaneously on a subject, possibly due to the rate being a product of entrainment between patient and practitioner.

## Mobility of the intracranial and intraspinal dural membranes
The membranes surrounding the brain and separating the left and right halves and the cerebrum from the cerebellum are continuous with the spinal dura, and share the same fluctuating rhythm. In 1970 Upledger observed during a surgical procedure on the neck what he described as a slow pulsating movement within the spinal meninges. He attempted to hold the membrane still and found that he could not due to the strength of the action behind the movement.
In craniosacral treatment the membranes act as a fulcrum for fascial restrictions throughout the body, and craniosacral therapists may perceive a change in quality as a result of disturbance such as infection or allergic irritation.

## Mobility of the cranial bones
Cranial sutures are often believed to be immobile after fusion, preventing cranial bone movement. This belief arose in the mid-1900s. According to Lee 
this belief was misinterpreted from the work of authors hoping to correlate suture closure with the chronological age of a skull in archaeological specimens. The authors not only found that there was no correlation between suture closure and the chronological age of the individual, but also that most skulls demonstrated no suture closure at all except as structural evidence of pathological physical trauma. Lee cites many references giving evidence for mobility in human skulls,
and modern anatomy books suggest incomplete fusion of some sutures, for example: "Sutural ligaments may effect an almost immovable bond between large areas of bone... but such immobility cannot be effected at narrow edges of bones in the cranial vault," 
and: "When such sutures are tied by sutural ligament and periosteum, almost complete immobility results."
It is usual in cranial textbooks to say that the motion of the skull is possible during flexion and extension because the sutures are mobile, especially the spenobasilar synchondrosis (SBS) - the junction between the base of the sphenoid and the occiput. Positional descriptions of cranial lesions traditionally relate to the relationship between the sphenoid and the occiput at this junction. An alternative theory to SBS motion taught in craniosacral training suggests that sutures are "lines of folding", like pre-folded marks on cardboard, rather than necessarily being fully open.

## Mobility of the sacrum between the ilia
Mobility of the sacroiliac joint is not contested, although the fulcrum of craniosacral movement is through the body of the second sacral vertebra or segment (S2). The cranial concept recognises the link between the sacrum and occiput via the spinal dura, which is attached to the anterior of the sacrum at S2: as the occiput goes into extension the sacrum nutates, and the converse also occurs. The occiput can therefore be influenced by treatment of the sacrum, and vice-versa.

# Craniosacral treatment
A typical craniosacral therapy session is performed with the client fully-clothed, in a supine position, and usually lasts about one hour. In the Upledger method of craniosacral therapy, a ten-step protocol serves as a general guideline, which includes (1) analyzing the base (existing) cranial rhythm, (2) creating a still point in that rhythm at the base of the skull, (3) rocking the sacrum, (4) lengthening the spine in the lumbar-sacral region, (5) addressing the pelvic, respiratory and thoracic diaphragms, (6) releasing the hyoid bone in the throat, and (7-10) addressing each one of the cranial bones.  The practitioner may use discretion in using which steps are suitable for each client, and may or may not follow them in sequential order, with time restraints and the extent of trauma being factors.
The therapist places their hands lightly on the patient's body, tuning in to the patient by listening with their hands or, in Sutherland's words, "with thinking fingers". Therapeutic contact between the patient and therapist may involve entrainment between patient and practitioner. 
Patients often experience a sense of deep relaxation during and after the treatment session, and may feel light-headed. This is popularly associated with increases in endorphins, but research shows the effects may actually be brought about by the endocannabinoid system.
Craniosacral therapy is claimed to be particularly beneficial in children.
Adverse side effects of treatment are uncommon: in a study of craniosacral manipulation in patients with traumatic brain syndrome the level of adverse effects from treatment was 5%.
Postgraduate study at the UK Osteopathic Centre for children can lead to the award of an MSc in Paediatric Osteopathy.

# Training and accreditation
Craniosacral therapy is not protected by statute either in the US or the UK, and there is currently no legal requirement to be trained to any standard or registered with a professional association. In the UK the Health Professions Council is consulting on whether to integrate all craniosacral therapists in the UK under their umbrella of state regulated professions.

## Accreditation and training in the US
In 1985, Dr. John Upledger established the Upledger Institute, a health center based in Florida and dedicated to the education and certification of practitioners in craniosacral and related therapies. An Upledger certification in CranioSacral therapy involves four levels of training and an overview of practice.  In the most basic introductory CranioSacral courses of the Upledger Institute, training is restricted to people with some background in anatomy and health care.
Certified training in Biodynamic Craniosacral therapy, by Dr. Franklyn Sills (a further development of Dr. Sutherland's investigation into cranial osteopathy), takes three years to complete.
Originally kept in the domain of chiropractors and osteopaths, craniosacral therapy has been opened up to those with less medical training, due to its broad healing potential and that its gentle manipulations do not pose a threat to the body.

## Accreditation and training in the UK
There are currently two different organisations in the UK offering registration of practitioners graduating in craniosacral therapy, the UK Craniosacral Therapy Association (CSTA), whose members may use the postnominal letters 'RCST', and The Cranio Sacral Society, based in Perth, Scotland and founded in 1993. The CSTA validates five training colleges, and the The Cranio Sacral Society offers regulation for those with postgraduate training with The Upledger Institute. Both registering bodies are self-governed and have their own code of ethics. They have made moves towards amalgamation into a common register via the Forum for Cranial Practitioners, but the diversity of their training programmes has prevented this.

## Accreditation and training in AUST
Training in Australia is provided by Stillness Trainings in sydney,  the Craniosacral Academy of Australia in Adelaide. Craniosacral Australia Also available is training in Biodynamic Craniosacral therapy, with Roger Gilchrist and Polarity Therapy.

# Criticisms
Skeptics existing both inside and outside the osteopathic profession level the following criticisms at craniosacral therapy:
- Lack of evidence for the existence of "cranial bone movement"
- Lack of evidence for the existence of the "cranial rhythm"
- Lack of evidence linking "cranial rhythm" to disease
- Lack of evidence "cranial rhythm" is detectable by practitioners