This area of Biological Dentistry deals with the structural balance that influences our neurological, mental, emotional and physiological health. The Cranial, Dental, Sacral Complex is composed of our cranium, dental arches and teeth, spinal column and sacrum area.

Imagine our skeletal system as our skull held over our shoulder girdle by the neck and our spine positioned over our pelvic girdle. In other words, the human skeletal body consists of a spinal column with the head bone at one end and the tailbone at the other. Like all the other structures, balance is the key in stability.

Dr James Carlson observed that parallel relationships exist in the structurally stable human body (figure 1) which permit it to maintain balance. These parallel planes include the ear plane, eye plane, shoulder plane, elbow and knee planes and pelvic plane. Dr Carlson’s observation revealed that the upper jaw or maxillae was another anatomic part that was also parallel to these other planes.

All the bones of the skull are connected not only through joints and/or sutures but also by muscles and the dural sheath (also known as the dural tube, dural membrane or meningeal membrane.)


Figure 1. The Parallel Planes of the Body (Courtesy of Dr Gerald Smith)

All the bones of the skull are connected not only through joints and/or sutures but also by muscles and the dural sheath (also known as the dural tube, dural membrane or meningeal membrane.)

The dural tube (Figure 2 below left) is the tough, fibrous, thick, inelastic covering of the dura matter (brain). Its primary function is protection. This membrane, which is attached to the inside of the cranium (figure 3 below right), passes down to the spinal column, attaches to the first three cervical vertebrae, then travels down to the sacrum and ends at the second sacral tubercle.


Figure 2. The dural tube is a continuous membrane that surrounds the brain, passes out of the base of the skull, attaches to the first three cervical vertebrae, and continues down the spinal cord where it finally attaches to the sacrum. This tube is the source for structural disturbances being transmitted from one part of the body to another. Because the body works reciprocally, imbalances in the skull can influence the neck, lower back, and pelvis and the reverse is also true. (Courtesy of Dr Gerald Smith)


Figure 3: The cranial dural membranes act as stabilizers to the vault bones. Physical trauma (whiplash injuries, blows to the head, forceful tooth extraction, etc.) and dental malocclusions have the potential to disrupt dural membrane balance and normal cranial rhythm. Such changes can cause adverse neurological function throughout the body. (Courtesy of Dr Gerald Smith)

Closer to home for me, the upper teeth are set in the maxilla. The maxilla is not just a jaw, it represents the front third of the cranial base. If the upper jaw is distorted (crooked teeth, crossed bite, one side higher than the other, canted maxilla, etc.), then the forces generated by the unmatched biting teeth can distort the skull. To make things even more complicated, in the head and neck region there are 136 muscles. Muscle tension or spasm can influence cranial motion. Among these muscles are the muscles of mastication (chewing). Since these muscles are all attached to the skull, improper bite can often trigger muscle spasms, which in turn can jam the sutures and distort the cranial bones.

As if this were not enough, dental malocclusion (bad bite) like deep bite, cross bite (front or back), a constricted narrow upper arch, faulty crowns or dentures, high cant of maxilla, or under-developed lower jaw can all contribute to cranial distortion. Please read on to find out why this is so important.

Cranial Motion
The combination of the elements in the body of man is more perfect than the composition of any other being; it is mingled in absolute equilibrium, therefore it is more noble and more perfect. — Baha’i Writings

In 1939, Osteopath William Sutherland discovered that there is a rhythmic motion to our cranium. The adult cranium (figure 4) is composed of 28 bones. These bones are attached together at junctions called sutures. In the past, sutures were considered immovable joints, however the work of Dr John Upledger proved that these sutures were viable structures (figure 5).


Figure 4: The cranium is a dynamic structure that is in a constant state of micro-motion. This motion can occur because of the inherent flexibility of bones plus the presence of the expansion joints or sutures that lie between each bone. Architects design buildings, bridges and roads with specific leeway for expansion, contraction and torsion. Nature likewise provides for similar allowances in the flexibility of its hard and soft tissues and their interconnections. (Courtesy of Dr Gerald Smith)

The origin of cranial motion is thought to be the brain cells, so just as the lungs rhythmically contract and expand through breathing, so does our cranium. This cranial motion is also known as Primary Respiratory Mechanism (PRM). PRM is independent of all other body rhythms like heartbeat, breathing, and the waves of movement that pass food along the intestines.


Figure 6: The cerebrospinal fluid (CSF) is produced by choroid plexuses within the ventricles of the brain. Increased production occurs with increased stimulation of the parasympathetic (PNS) part of the nervous system. The PNS is located primarily in the cranium and sacral part of the body. Distortions of the skull bones or pelvic area have the potential to cause an increased quantity of CSF and raise intracranial pressure. (Courtesy of Dr Gerald Smith)

This cranial motion can further be divided into two basic micro-motions: primary and secondary. Primary micro-motion involves the independent movement of the skull and spinal cord, which facilitates the movement of CSF, articular motion of the cranial bones and involuntary motion of the sacrum. Secondary cranial respiratory motion synchronizes with our breathing cycles of inhalation and exhalation. Inhalation expands the cranium while exhalation reduces it. Both primary and secondary respiration is coordinated by the dural tube. This tube is the source of structural disturbances transmitted from one part of the spinal column (Sacrum) to the other (skull). Because our skeletal system works reciprocally, any imbalance in the cranium can effect the neck, lower back, pelvis and vise versa (figure 7.)


Figure 5: Scientists have documented the existence of nerves, blood vessels, and connecting fibers in the sutural areas. Anatomists have also shown the direct physical connection between the inside and outside of the skull. The dural membrane that surrounds the brain communicates with and influences the outside of the skull by means of an outer fibrous layer. This layer passes through the sutures and covers the bony portions of the skull.

For this reason, internal tension has the potential to cause external changes such as muscle spasm (a migraine patient’s scalp can become sore from simple brushing ) and vice-type pressure. The reverse is also true. Whether the headache is due to physical tension or a vascular migraine, the dural membrane will be affected. (Courtesy of Dr Gerald Smith)

PRM is felt as the expansion and contraction of the head and body. The mechanism is characterized by the light movement of the bones of the skull and the sacrum, the dural tube and the central nervous system with the flow of cerebrospinal fluid (CSF) (figure 6). Sutherland did experiments on himself by restricting various bones of his head. He experienced both adverse physiological changes throughout his body and unpleasant emotions. He then concluded that good physiological and mental health depends not only on the bones of the cranium being in the right position, but also on the ability of the sutures to allow this micro-motion to happen.


Figure 7: In reality, the body functions just like a slinky. A distortion at one end will be reflected to its area of compensation. For example, the bones of the hands and feet work reciprocally as well as the ankle and wrist, knee and elbow, pelvis and shoulders. One of the main connecting links of the body that enables this slinky effect to occur is the dural tube. Joint receptors and neuromuscular biofeedback provide other means by which the body functions reciprocally.
(Courtesy of Dr Gerald Smith)

I hope it has become clear that imbalances in any part of this system can interfere with cranial motion and cause disease in our system. Physical traumas such as whiplash injury to the neck or pelvis trauma from falling off a horse, bad posture caused by working in front of computer extensively, and dental problems such as bad bite are examples of things that can disturb the balance in the system. These can cause cranial distortion and restrict cranial motion eliciting clinical symptoms such as headache, dizziness, numbness, muscle spasm, faulty digestion, jaw pain, irregular heart beat, tinnitus, migraines (figure 8), circulatory problems, chronic fatigue, sinusitis, constipation, neck ache, shoulder ache, eye pain, and facial pain.


Figure 8: Migraine headaches usually affect one-half of the victim’s head. Since the dural tube is a reciprocating membrane, tension or torquing in the skull will cause one side to be in traction while the other side provides the slack. The nerves passing through the tensioned side will be responsible for the varied and extensive pains. The dural torquing can result from a single or various combinations of structural distortion involving the pelvis, spinal vertebrae, dental malocclusion or cranial bone restrictions. These structural problems can be triggered by emotional, physical, nutritional or physiological stressors (e.g. organ dysfunction, under-active thyroid, muscle spasm or weakness, fixed and removable dental bridgework) (Courtesy of Dr Gerald Smith)

Closer to my area of expertise, patients with a deep overbite, underdeveloped lower jaw, cross bite, or collapsed bite may experience cranial distortion and dural torque. Many of them suffer from headaches, migraines, neck and shoulder stiffness and lower back pain. Some may have itchiness or stuffiness in the ears and many have clicking jaw joints.

Among the other dental conditions is conventional orthodontics that involved the amputation of premolar teeth to mechanically achieve esthetic arches by moving back the upper six front teeth. This caused restriction of the maxilla, palatine, vomer and sphenoid skull bones and contributed further to an already forward head position and loss of normal curvature of the cervical vertebra. Studies have shown that patients with the above treatment have a limited neck movement and compressed upper cervical vertebra especially at the level of C1 to C3. They are already at a disadvantage with regard to their dental, cervical and cranial balance. If these individuals are involved in an accident and experience a whiplash injury to their neck, they will never fully recover unless their structural imbalance is addressed.

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