The Dura Mater is the outermost layer of the meninges which cover the brain and spinal cord. It is composed of thick, dense, white, inelastic, fibrous connective tissue.
Cranial Dura Mater
Within the cranial vault the dura mater presents both an outer, endosteal layer and an inner meningeal surface. The two layers are connected by fibers which intersect each other obliquely.
The endosteal surface of the dura mater is rough and fibrillated and adheres closely to the entire inner surface of the cranial bones, forming their internal periosteum and containing blood vessels for their supply.
The inner, meningeal surface is smooth and lined with a layer of endothelium similar to that found on serous membranes. By its reduplication the meningeal layer of the cranial dura mater forms the falx cerebri, the tentoria and falx cerebelli and the diaphragma sella.
The cranial dura mater attaches firmly to the entire circumference of the foramen magnum of the skull before exiting the cranial vault.
Dural Membrane Tension
Upledger, et Al report that “when the dural membrane of the cranium is subjected to tension in a certain direction over time, the fibers within the membrane seem to organize and align themselves with the direction of tension. Study of the fiber organization patterns may disclose the direction of principal tensions to which the membranes were subjected during life.”
Spinal Dura Mater
As the cranial dura mater exits the skull, the endosteal layer ends at the foramen magnum posteriorly, but reaches as low as the 3rd cervical vertebra anteriorly, blending with the periosteum of the 2nd and 3rd cervical vertebrae. Below this level, its place is taken by the periosteum of the vertebrae. The remaining spinal dura mater is made up almost entirely of the meningeal layer of dura, white, fibrous connective tissue arranged in bands oriented longitudinally.
Spinal Dura Attachments
Hack, et Al, -Spine 1995- reported a dural connection to the atlas vertebra. Their findings on dissection were that the posterior atlanto-occipital membrane was intimately blended with the fibers of the dura mater.
Hack observed the presence of a “connective tissue bridge” between the posterior atlanto- occipital membrane and the rectus capitus posterior minor muscle.
The researchers observed that in all cases, extension of the head and neck produced an “infolding” of the dura mater. The authors concluded that the connective tissue “bridge” between the PAO membrane and the rectus capitus posterior minor muscle was a mechanism by which this “infolding” or “pleating” of the dura mater was restricted by tension present in the RCP minor muscle during head and neck extension. This would protect the flow of cerebrospinal fluid during head extension.
Mitchell and Humphrey’s- JMPT 1998 – reported the presence of a connective tissue “bridge” between the 1st and 2nd cervical vertebrae from the ligamentum nuchae. These authors also speculate that the presence of this connection is to reduce the movement of the dura mater with extension of the cervical spine. These authors also cite the fact that the dura mater is thicker posteriorly than anteriorly in the region of C1 – C3, making it more resistant to “infolding”.
The spinal dura mater forms a sheath which surrounds the spinal cord and is separated from the bony walls of the spinal canal by an epidural space containing loose areolar tissue and a plexus of veins. As stated before, the dura mater is firmly attached to the 2nd and 3rd cervical vertebrae and is also attached, variably, to the posterior longitudinal ligament by fibrous slips. These slips tend to be denser toward the lumbar region of the spinal canal.
At the level of the 2nd sacral segment, the dural tube narrows and becomes impervious. Here, it ensheathes the filum terminale and descends through the sacral hiatus to the back of the coccyx where it blends with the periosteum. Most authorities tend to agree that the dura mater of the spinal cord attaches to the anterior surface of the sacral canal at the level of the 2nd sacral segments.
The “Core Link” between the Cranium and Spine
Tensions developed within the cranial dura mater may be transmitted to the spine and pelvis through the connections described earlier at C1, C2, C3, the sacrum and finally, the coccyx.
As this dural tension is applied to the vertebrae of the spinal column misalignment and imbalance will occur. The upper- cervical vertebrae, ligaments, and muscles play a key role in the so-called “righting reflex” which strives to keep the eyes level to the horizon and the center of gravity between the feet. Any misalignment in this vital area will result in further distortion of spinal architecture below resulting in a “globally subluxated” spinal column.
When the tensioning and torque placed on the sacrum and coccyx from the cranial dural tension above is added to the equation, we have even further misalignment of the spinal structures. Thus, the “unstable spinal vertebra” or the “chronic subluxation” so often encountered by practitioners may very well be the effect of the cranial distortion above.
This dura- mediated spinal misalignment pattern can not be effectively addressed with methods aimed solely at spinal correction. Something must be done in order to release the tension within the dura mater before any lasting correction of the spine can be effected.
The Cranial Nerves
Each of the cranial nerves is wrapped in a sheath of dura mater. As they exit the cranial vault they are described by Gray’s Anatomy as having a “dural cuff”. Adverse tension and traction within the cranial dura may be transmitted to these dural sleeves resulting in less than optimal function of the nerve involved.
One such situation exists with the optic nerve. Outside the main skull cavity the optic nerve is wrapped in dura mater and the sclera of the eyeball is a continuation of this dura. It is noted in many physiology texts that increased pressure in the cerebrospinal fluid within the dural sheath of the optic nerve has ramifications for the function of this nerve.
In light of the positive changes in vision often times noted by recipients of the CRT Process, the question must be asked as to whether the dural tension developed by cranial bone misalignment and its transference to the optic nerve sheath and sclera can be partially to blame.
The Pituitary Gland
The pituitary gland is nestled within the sella tursica of the sphenoid bone. The sella tursica is covered over by a layer of the meningeal dura mater called the diaphragma sella. The diaphragma sella is “pierced” by the infundibulum, the stalk which connects the pituitary gland with the hypothalamus.
The hypothalamus monitors the extra cellular environment which must be kept constant in regards to acid/base balance, water volume, temperature and concentration of dissolved substances needed for cell metabolism and repair. One of the mechanisms used by the hypothalamus in order to ensure constancy in this environment is the pituitary gland.
These two glands are in constant communication with one another through the infundibulum. This communication is accomplished by means of neurosecretions from the hypothalamus into the blood vessels of the pituitary gland. It is also carried on by the release of secretory product (Herring Bodies) into the neurohypophyseal tracts between the hypothalamus and pituitary gland.
In light of the positive results many times achieved with CRT and endocrine disorders, the question must be asked as to whether some negative effect upon hypothalamic – pituitary communication is exerted as the cranial vault dural tension is transmitted to the diaphragma sella and the to the infundibulum piercing it.
The epineurium is the outer connective tissue covering of a spinal or peripheral nerve. This epineurium is a “continuation” of the dura mater. In effect, the nerves running all the way out to the tips of the fingers and toes are covered with a continuation of the dura mater. Thus, tension developed within the cranial and spinal dura may be transmitted to these nerves as well perhaps resulting in the many of the “unexplained” peripheral neuropathies encountered in practice.
The fascia may be thought of as a single, laminated sheet of connective tissue which runs without interruption from the top of the head to the tips of the toes.
The fascia contains what might be called “pockets” for the presence of organs, muscles and skeletal structures as well as areas reserved for the passage of the vertebral column and central nervous system. As the nerves exit the spinal canal and proceed out to the periphery their epineurial coverings blend with and become continuous distally with the fascia. Upledger discusses the direct relationship of 4 -5 layers of fascia to the cranium itself.
Suffice it say that cranial dysfunction with resulting tension referred into the fascia can have very far reaching effects on virtually all systems and tissues of the body.
It should be noted as well that any damage or dysfunction of the fascia, through surgical procedures, injuries, inflammation and such, will have the effect of creating “drag” or tension within the craniosacral system.
The author has also made observations, in the dissection lab, of the presence of firm adhesions of the spinal dura to segments of the spine affected by any type of local inflammatory process such as those encountered with spinal injury, disk lesions, spondylosis, etc.
The factors noted above will serve to intensify the existing cranio – dural stress and its ramifications on body function. It may also make correction and release of the CDSS a bit more involved than the norm.
Upon investigation, it becomes quite clear that Cranio – Dural Stress has potentially far-reaching effects on the health and vitality of the organism. The nervous, structural, muscular, endocrine and organ systems of the body are intimately associated with the dura mater and fascia. Abnormal cranial function and its related tension may place great stress on any or all of the systems listed.
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