"The doctor of the future will give no medicine, but will interest his patients in the care of the human frame, in diet and in the cause and prevention of disease." - Thomas A. Edison

Peter Varley BDSc, FDSRCS, DFHom(Dent.) and Richard Holding DO, MRO.(profile)

Introduction

Osteopathy was founded in 1892 when Dr A.T. Still, a doctor and travelling preacher from Kirksville, Missouri, founded the American School of Osteopathy. DR Sutherland was a student of DR Still’s noticed a disarticulated skull in his office he questioned why the sutures were beveled in a manner that suggested motion.

Since there are no muscular agencies between the bones of the skull, the question ‘How did the cranium move?’, took DR Sutherland into another area of study; the dura mater. Looking at the whole cranial-sacral inelastic dura as a total interconnected mechanism, where if one part moved everything moved, he was able to explain the changes in bevel in the sutural articulations in terms of applied anatomy. He was then able to describe the changes in the shape of the skull that could be expected from these changes in sutural bevel.

Dr. Sutherland now had the basis of an new anatomical physiological system of cranial motion. This included:

• A fluctuation movement of the cerebro-spinal fluid.
• The reciprocal tension of the dural membranes.
• Motility in the brain.
• Motility of the 22 cranial bones and the sacrum between the ilea.

What was left was to find out how clinically relevant this movement was and how it could be utilised in the treatment of peoples’ health problems.

After twenty years of research he was able to demonstrate that the craniosacral mechanism’s motion was not just clinically important but vitally important to the proper functioning of the individual’s physiology. The motion was shown to have the following characteristics:

• It is involuntary.
• It has a respiratory function.
• It has a lubricating function to the whole spinal cord.
• It controls venous return in the skull.
• It provides drainage and balance to the orbit eight bones.
• It is independent of thoracic respiratory motion.
• It is independent of arterial fluctuation.

Skills Required in Cranial Therapy

Dr. Sutherland emphasised that osteopathy, with its cranial approach, ‘is a science that deals with the natural forces of the body’. The basic skills that we need to learn are not a collection of techniques but the following:

Right and Left Brain Awareness

One of the skills needed by practitioners using the craniosacral approach is the integration of right and left brain awareness. Those people who are right brain dominant rely on their intuition to tell them what is happening under their hands. Those who are left brain dominant tend to learn this approach through the analytical and systematic application of anatomy and physiology. Unfortunately, the use of either of these approaches to the exclusion of the other will not allow the real beauty of this way of working to be appreciated.

Gentle Touch

Our touch should be very light and gentle. In fact the more gentle the touch, the less invasive we are and the more the tissues under our hands are able to demonstrate what they wish to do. If we apply too great a pressure, then the system locks up and we feel nothing.

The Primary Respiratory Mechanism

Physiological Effects of Involuntary Motion in the Tissues

There are at least three different ways that this involuntary motion affects the tissues:

1. It acts as a powerful hydraulic system that initiates balanced interchange between all the tissues of the body.
2. It has a lubricating function, which enables the tissue to protect itself against stress and trauma.
3. The involuntary motion of the primary respiratory mechanism is the primary energetic system of the body. The level of activation of other energetic systems, eg. Qi energy is dependent on it.

The craniosacral system is the primary respiratory mechanism of the body. Physiologically it is the highest known element in that it carries ‘the breath of Life’ into the tissues.

Careful balancing of the primary respiratory mechanism will correct unwanted adaptation to stress, trauma and disease. The more efficiently the primary respiratory mechanism functions, the more the body is able to resist trauma and disease in the future.

Although DR Sutherland stressed that the primary respiratory mechanism was a unit of function, he recognised that it is easier to understand if it is broken down into four constituent parts of CSF, dura, brain and bones. He believed that the constituent parts have a hierarchy of function, which he listed in the following order:

• The fluctuation of the cerebrospinal fluid
• The reciprocal tension of the dural membranes
• The motility of the brain and spinal cord
• The mobility of the 22 cranial bones and the sacrum between the ilia.

Fluctuation of the Cerebrospinal Fluid

An understanding of the potency within the fluctuation of the cerebrospinal fluid (CSF) is central to the cranial osteopathic approach. Cerebrospinal fluid fluctuates in a rhythmic fashion. This fluctuation provides a driving force towards normal function. It can be harnessed internally by the homeostatic mechanisms of the body and externally by the physician to achieve homeostasis using the dural membranes to induce balance in tissues.

The Reciprocal Tension of the Dural Membranes

The dural membranes are a tough and inelastic sheath for the whole brain and spinal cord. The concept of reciprocal tension can be likened to the operation of a mobile; when one part moves, the remaining parts will shift to adapt to this change.

Reciprocal tension is made possible by the cranial dura forming three sickle shaped membranes called the falx cerebri (the midline membrane) and the two tentorium cerebelli (the lateral membranes). The significance of this is that if there is a shift in the functional position of the dura, then the cranial bones en masse have to move also.

Articular Poles of Attachment

There are six articular poles where the dura attach to various points inside the skull. One can visualise that they move in different directions during the flexion and extension phases of motion.

Flexion Phase of Motion

The skull shortens in the anterior posterior plane and widens in the lateral plane.

Extension Phase of Motion

The skull lengthens in the anterior posterior plane and narrows in the lateral plane.

Cranial Patterns of Movement

In optimum health, the capacity of the craniosacral mechanism for flexion and extension is evenly balanced. If, however, the craniosacral system has had to adapt to trauma or disease, the dural membrane will express itself in one of the following patterns:

1. Exaggerated flexion
   All quadrants are held in external rotation.
2. Exaggerated extension
   All quadrants are held in internal rotation.
3. Sidebending rotation or ‘cranial bulge’
   Both quadrants on one side are held in external rotation, whilst the opposite quadrants are held in internal rotation.
   
   The above three movements are what we call physiological constricted movements. The next three movements are pathological.
   
4. Torsion or ‘cranial twist’
   The anterior quadrant on one side is in internal rotation whereas the posterior quadrant on the same side is in external rotation; on the opposite side, the anterior quadrant is in external rotation and the posterior quadrant is in internal rotation.
5. Lateral strain or ‘cranial shear’
   Both anterior quadrants are shifted laterally in one direction whereas both posterior quadrants are shifted laterally in the opposite direction.
6. Vertical strain or ‘cranial shear’
   Both anterior quadrants are shifted in a superior direction whereas both posterior quadrants are shifted in an inferior direction or vice versa.

Cranial techniques can be useful to dentists before and after adjusting occlussal splints and orthodontic appliances, and also after the extraction of teeth or any other potentially traumatic application to the maxilla, mandible or surrounding bones.

The Inter-relationship between Cranial Osteopathy and Dentistry

The relationship between the mandible and the temporal bones is reciprocal in that the position of the temporal bones can alter the occlusion just as the occlusion can affect the position of the temporal bones.

'If the cranium is the pump for the cerebrospinal fluid, then the mandible is the pump handle.' (W. B. May, personal communication).

When assessing the occlusion and the TMJ it is important to consider the effects of the cranial mechanism. The following simple but effective diagnostic procedures should be useful.

• During assessment of Cranial Rhythmic Impulse (CRI), if the CRI decreases when the jaw is closed, then it is reasonable to suspect the jaw as a limiting factor in cranial motion. If the CRI increases with the jaw closed, this indicates that the occlusion is helping to correct a cranial fault.
• Palpate the muscles of the TMJ for hypotonicity, hypertonicity and trigger points.
• Place the little fingers in the external auditory meatus and ask the patient to close his jaw. If this produces excess pressure on the fingers and/or pain in the joint, the mandible is being pushed too far posterior on closure and may need to be corrected with an anterior mandibular repositioning appliance.

Some categories of overlapping interest between the dental and the osteopathic professions in the area of the TMJ:

• Developmental problems.
• The effects of dental trauma on the cranium.

Developmental Problems

We know that sometimes the normal overriding of the neonate cranial bones within the birth process fails to be cleared by the suckling at the breast or crying.

We also know that possible warping or crowding of the foetal skull in utero can occur secondary to maternal stress. Major trauma to the neonate skull can occur in the birth process from factors such as disproportion, abnormal presentations, forceps, induced births or maternal fatigue.

The Effect of Cranial Development on the Occlusion

The relative balance of the infants posture, not just of the spine but of the TMJ, is intimately connected to the relationships of the two temporal bones to each other, the sphenoid to the occipital bone and the maxillae to the mandible. When assessing the occlusion and the TMJ in relationship to developmental problems in these cranial bones, it can be evaluated in at least three ways:

• When there is a change in the spatial relationship of the two temporal bones.
• When there is a change in relationship between the sphenoid bone and the occipital bone without any major twist between them.
• When there is a change in the relationship between the mandible and the maxillae in their transverse planes.

Early co-operation between dentists and osteopaths is fundamental to these young children. Everything flows from here, if the infant is corrected after birth by either a dentist or an osteopath with craniosacral skills, the only problems that should occur with the development of the bite and the rest of the posture will be from postnatal trauma, malnutrition or genetic factors.

The Effects of Dental Trauma on the Cranium

It is not only that cranial distortions affect the occlusion but that occlussal problems may have an effect on the cranium. It is not a one way street. Some common occlussal problems are:

• Lack of Vertical Dimension
  Lack of vertical dimension will limit cervical mobility, especially in the area of C3. A good check is to increase the vertical dimension of the bite and observe if there is an increase in cervical rotation.
• Lack of Posterior Support for the Bite
  Lack of posterior support to the bite (i.e. posterior molars missing) will cause weakness of the psoas, lumbar and abdominal muscles during lifting. This is because the usual reflex during lifting is to clench the teeth to stabilise the craniomandibular complex. If however, there is no posterior support to the bite, this reflex is inhibited.

Conclusion

As the biomechanics of the craniosacral mechanism become more widely appreciated, certain dental procedures such as extractions, orthodontics and splint work can be developed utilising the palpatory skills that are taught within the postgraduate osteopathic teaching programme for the craniosacral system. This will have major repercussions in our patients’ health and greatly facilitate our working with the more difficult or problem patient.

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