Wisdom in the Body

by Michael Kern

  The existence of a primary energy center is also recognized in biodynamic craniosacral therapy. The area of the third ventricle is considered the site of the original fulcrum that is formed at conception and through which the organizing potencies of the Breath of Life first become expressed. In this process the blueprint for the formation of the whole human being becomes laid down and starts to organize the cellular differentiation and development of the body.

  Dynamo motion

  It is considered that C.S.F. becomes potentized with the Breath of Life mainly in the third ventricle.41 It is here that the biodynamic potencies of the Breath of Life become transmuted into the fluid. It is no coincidence that the walls of the third ventricle contain some of the most crucial nerve centers and glands for the physiological balance of the body, as these vital structures are able to benefit from the immediate contact of this freshly potentized C.S.F.

  Much newly formed C.S.F. enters the third ventricle through openings in the front part of its roof, coming from its main sites of production in the lateral ventricles above. It then circulates around the solid hub of the third ventricle, in a motion that has been likened to that of a dynamo (see Figure 3.8). It is within the activity of this dynamo motion that the spark of life is thought to enter the C.S.F.

  Ignition

  The third ventricle is considered a critical junction between the vital potencies of the Breath of Life and its manifestation in the body. A process of ignition occurs within the fluids as the creative intention of the Breath of Life enters the body through this primary fulcrum. This ignition produces the “spark in the motor” referred to by Dr. Sutherland that drives the longitudinal fluctuation of C.S.F. and brings the organizing potencies of the Breath of Life into the body. This process is vitally important for the proper incarnation and embodiment of the organizing forces of the Breath of Life. Many chronic health conditions, often involving a variety of seemingly unrelated symptoms, can be traced to a problem with the ignition process. Ignition quite frequently operates with sluggishness due to the presence of strain or trauma.

  Figure 3.8: Circulation of cerebrospinal fluid around the third ventricle (illustration credit 3.8)

  Fourth ventricle

  The fourth ventricle is located below the third ventricle, and is connected to it by a long narrow channel called the Aqueduct of Sylvius. The fourth ventricle is a rhomboid-shaped cavity filled with C.S.F. It is also of great importance for the maintenance and regulation of health because its walls contain many of the major nerve centers of the body, including those that control lung breathing (secondary respiration), blood circulation, digestion, elimination, homeostasis and ten of the twelve cranial nerves. These tissues, vital for physiological functioning, likewise become bathed with freshly formed and potentized C.S.F., carrying the ordering principle of the Breath of Life.

  3) The Mobility of the Reciprocal Tension Membrane System

  The central nervous system is contained within a system of connective tissues called meninges. There are three layers of meninges and they are an integral part of the primary respiratory mechanism (see Figure 3.9).

  The inner layer of meninges is similar to plastic wrap (or cling film) as it closely follows all the contours and convolutions of the brain and spinal cord. This layer is called the pia mater and is very thin and delicate.

  The middle layer of meninges is called the arachnoid because it resembles a spider’s web and is also thin and delicate. The arachnoid and pia mater are connected by thin strands of tissue with a space between called the subarachnoid space. It is within the subarachnoid space that C.S.F. circulates around the central nervous system.

  The dural system

  The outer layer of meninges is called the dura mater. Dura means strong and mater means mother, so this tissue is considered a strong mother! This tough and fibrous membrane is actually formed of two layers that are largely fused together. However, at certain points in the skull the two layers of dura separate from each other. The inner meningeal layer splits away, while the outer periosteal layer adheres to the internal surfaces of cranial bones. At the places where the meningeal layer splits away, folds of tissue are created, forming membranous partitions for the brain. These folds of dural membrane create strong vertical and horizontal sheets of tissue that help regulate the motion of the primary respiratory mechanism. Furthermore, venous sinuses are formed where the layers of dura separate (see Figure 3.9). These important channels drain both blood and reabsorbed cerebrospinal fluid from the head.

  Figure 3.9: Cranial meninges and the formation of a venous sinus (illustration credit 3.9)

  The continuous system of connective tissue formed from dural membranes is called the reciprocal tension membrane system (see Figure 3.10).

  Figure 3.10: Cranial reciprocal tension membranes (illustration credit 3.10)

  Vertical partitions

  There are two vertical partitions, made of dura, for the brain. The large upper vertical sheet of tissue, called the falx cerebri, separates the right and left cerebral hemispheres. It is a sickle-shaped membrane that traverses the underside of the top of the skull from front to back. At the front, the falx cerebri is attached to the ethmoid bone (see Figure 3.10). It then passes beneath the frontal bone, runs under the suture between the two parietal bones and attaches at the back to the occipital bone. At the back it meets the horizontal partitions of dural membrane at an important junction in which the straight sinus is formed.

  The falx cerebelli is a smaller vertical partition beneath the straight sinus, separating the right and left hemispheres of the cerebellum. It is attached by a dense ring of connective tissue to the foramen magnum, a large opening in the floor of the occipital bone through which the lower part of the brainstem and top of the spinal cord exit the skull. The ring of tissue around the foramen magnum is then continuous with the spinal dura—the long tube of membrane that surrounds the spinal cord.

  Horizontal partitions

  Horizontal folds of dural membrane separate the upper and lower portions of the brain, forming a partition between the cerebrum and the cerebellum. This tissue has two leaves that form a tent-like structure across the back part of the skull. It is called the tentorium cerebelli. At its front end, the tentorium attaches to projections on the sphenoid bone called clinoid processes (see Figure 3.10). At the sides it is attached to the inner ridges of the temporal bones and to a small part of the parietal bones. At the back it attaches to the internal surface of the occipital bone. The two leaves of the horizontal tentorium meet with the vertical falx cerebri at the straight sinus in the midline.

  Reciprocal tension motion

  Dr. Sutherland named these tissues the “reciprocal tension membrane system” because they are maintained in a state of constant tension during all of their movements. Because the dura is both continuous and relatively inelastic, any motion that takes place in one part of the system is easily transferred to another. In this way, the reciprocal tension membranes function as a unified system. Primary respiration is expressed through this system as a tensile pushing and pulling motion, first in one direction and then in another.

  These membranes form an integral part of cranial rhythmic motion. During each phase of inhalation, the falx cerebri shifts anteriorly towards its attachment at the front and curls in on itself, narrowing from front to back (see Figure 3.11). The smaller falx cerebelli also narrows from front to back. Meanwhile, the tentorium flattens out and widens from side to side. It also moves forwards and rises where it attaches to the sphenoid bone at the front. The motion of these membranes coincides with a general narrowing from front to back and widening from side to side of the cranium during inhalation.

  In the exhalation phase the opposite motion occurs. The falx cerebri uncurls, moves posteriorly and lengthens from front to back. Meanwhile, the tentorium narrows from side to side and becomes more domed, as it takes on more of a tent-shape again.

  Figure 3.11: Inhalation/flexion phase of the reciprocal tension membranes (i
llustration credit 3.11)

  Sutherland’s fulcrum

  The junction formed at the meeting place of the falx cerebri, the tentorium cerebelli and the falx cerebelli, contains the straight sinus (see Figure 3.10). Sutherland’s fulcrum, an important leverage point or pivot around which the reciprocal tension membranes express their motion, is located at the front part of the straight sinus. The different partitions of the reciprocal tension membrane system can be thought of as suspending from this important fulcrum.

  A fulcrum has been described as a point of rest on which a lever moves and from which it gets its power.42 As such, Sutherland’s fulcrum is a significant place for the balanced motion of the reciprocal tension membrane system. It is actually a moving leverage point that shifts back and forth along the angle of the straight sinus during the cycles of primary respiration. It moves anteriorly and superiorly during inhalation, and posteriorly and inferiorly during exhalation. Any restrictions that affect the balance of this dynamic, shifting fulcrum can upset the functioning of the entire reciprocal tension membrane system—and beyond.

  Integrated motion

  In the early stages of our embryological development, the reciprocal tension membranes are formed from the mesenchym (the same embryonic tissue as cranial bones). Part of this tissue hardens during the first few years of life to form cranial bones, and part of it remains as the dural membranes inside the skull. Therefore, the dural membranes and cranial bones can be seen as different elements within a continuity of tissue. In their expression of primary respiration, these bones and membranes act together as an integrated unit of function. Because the membranes are relatively inelastic any pull or strain has an effect on the motion of cranial bones, as do the cranial bones on the membranes. Consequently, the reciprocal tension membranes have often been described as helping to transmit and guide the motion of cranial bones.

  Recognizing the synchronized motion between cranial bones and membranes, Dr. Sutherland referred to their restriction as a “membranous-articular strain.”43 It is not possible to have a strain in one without involving the other. Because the brain is enclosed and partitioned by the dural membranes, its shape and function can be influenced by them. Membranous-articular strains can thus limit the motility of the central nervous system, the motion of cerebrospinal fluid and the passage of fluid through the venous sinus system. The functioning of numerous cranial nerves that pass through the reciprocal tension membranes can also be affected. In fact, freedom of motion in the reciprocal tension membrane system is necessary for the proper functioning of all other aspects of the primary respiratory mechanism, which are either enclosed within it or directly attached to it.

  The core link

  The spinal dura is firmly attached to the occiput by a ring of connective tissue around the foramen magnum. From this point downwards it hangs relatively freely, encircling the spinal cord, until it reaches the bottom of the spine. Here it is firmly attached to the second vertebral segment of the sacrum (S2) (see Figure 3.12). However, the dural tube usually has some small slips of tissue that connect it to the second and third vertebrae of the neck and sometimes to the lumbar spine, but these attachments do not fix it firmly to these points. The dural tube provides protection for the spinal cord and acts as a container for the inner layers of the meninges and the enclosed cerebrospinal fluid (C.S.F.).

  Figure 3.12: The core-link; pulley-motion as the sacrum is rocked into flexion (illustration credit 3.12)

  Because the spinal dura is relatively inelastic, forces can be easily transmitted through it between the occiput at its top end and the sacrum below. The spinal dura thus provides an important link between the primary respiration of the pelvis and the cranium. This connection was called the core link by Dr. Sutherland.44

  During the inhalation phase of primary respiration, the spinal dura rises, following the upward movement of Sutherland’s fulcrum. The opposite happens in the exhalation phase. Dr. John Upledger describes a pulley-like motion, during which the occiput and sacrum are reciprocally rocked into their craniosacral motion (C.R.I.) by the spinal dura.45 When the occiput expresses its craniosacral motion in inhalation, the front part of the foramen magnum rises. This exerts a pull up along the front side of the dural tube, raising the front side of the sacrum and rocking it into flexion (see Figure 3.12). In the exhalation phase, a pull is transmitted along the back side of the dural tube, rocking the sacrum into extension.

  However, the dural tube can lose its natural ability to glide freely within the spinal canal. This can affect the motion of the sacrum, cranial bones, spinal vertebrae, the circulation of C.S.F and cause irritation of the spinal cord. This type of problem commonly results from a whiplash injury or other kinds of back strain.

  Summary

  Here is a summary of the natural motion of the different parts of the reciprocal tension membrane system. During the inhalation phase of primary respiration:

  The falx cerebri shifts anteriorly towards its attachment at the ethmoid bone at the front, and shortens from front to back.

  The falx cerebelli shortens from front to back.

  The tentorium moves anteriorly, flattens and widens.

  The membrane system as a whole moves up and shortens from top to bottom.

  The spinal dural tube rises.

  This motion has its pivot around Sutherland’s fulcrum, located at the front part of the straight sinus. This is a moving, dynamic fulcrum that shifts position during the cycles of primary respiration.

  During the exhalation phase, the opposite motion occurs.

  An exercise

  To illustrate the integrated motion of the dural membrane system, imagine that your whole body represents these membranes. Stand with your knees slightly bent and your arms partly outstretched at the sides. Imagine that your legs and trunk are the spinal membranes, your head and neck is the falx cerebri, and your forehead is where the front end of the falx cerebri attaches to the ethmoid bone. Your arms represent the tentorium. To demonstrate how the membrane system moves in its inhalation phase, slowly straighten your knees. As your body rises bend your head forward and down so that your forehead curls slightly backwards as you tuck in your chin. At the same time, spread your arms wider from side to side.

  To demonstrate the exhalation phase, bend your knees to represent the lowering of the spinal dura. Uncurl your head, mimicking the action of the falx cerebri, and bring your arms closer to your body, following the motion of the tentorium. Interestingly, these movements are similar to some ancient Chi Kung exercises that apparently follow the natural designs of the body.46

  4) The Motion of Cranial Bones

  Dr. Sutherland began his investigations into primary respiration after recognizing the importance of cranial bony movement for our physiological functioning. There are twenty-two bones that form the adult human skull. Eight of these form the cranium that encloses and protects the brain, the “treasure in the citadel” (see Figure 3.13).47 Fourteen bones form the face (see Figure 3.14). In addition, there are three ossicles (tiny bones) in each ear. The eight cranial bones are:

  1 frontal bone

  2–3 parietal bones (2)

  4–5 temporal bones (2)

  6 occipital bone

  7 sphenoid bone

  8 ethmoid bone

  The fourteen facial bones are:

  1–2 nasal bones (2)

  3–4 maxillae (2)

  5–6 zygomatic bones (2)

  7 mandible

  8–9 acrimal bones (2)

  10–11 palatine bones (2)

  12–13 inferior nasal conchae (2)

  14 vomer

  Figure 3.13: Bones of the skull—side view (illustration credit 3.13)

  In accordance with the Greek legend, the cranial bones are carried on the shoulders of atlas, the name of the uppermost vertebra of the neck. The individual bones of the skull articulate with each other by a variety of differently shaped joints that allow for various kinds of movement. These specialized articulations in the
cranium are called sutures. It was while examining the design of these sutures that Dr. Sutherland first had the insight that they were intended for motion. As Dr. Magoun says,

  Why should there be articular surfaces at all if not for movement? Indeed the only factor physiologically capable of maintaining such joint surfaces throughout life … is motion.48

  Figure 3.14: Bones of the face—anterior view (illustration credit 3.14)

  Formation of sutures

  At the time of our birth, cranial bones still largely consist of either membrane or cartilage, and their sutures have not yet formed. Many sutures do not properly develop until about six years of age. The particular design that a suture acquires helps to determine the motion that can take place. However, there is also evidence to suggest that their design is at least partly formed as a consequence of the motion they express.49 In other words, the bones form according to how they function. This reflects one of the key principles in osteopathic medicine—the structure and function of the body are reciprocally interrelated (see Chapter 4).

  Some sutures are bevelled, with bones meeting each other at angled surfaces (see Figure 1.1). This design allows for a gliding or separating motion. Other sutures are serrated or corrugated, allowing for separation and a variety of hinge-like motions. Others are formed like sockets, allowing for rotatory or gliding motions. The shape of these “articular gears”50 is particular to each individual, and a unique expression of individual function. I have examined many skull specimens and have never seen two bones that are alike.