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INVOLUNTARY MOTION STUDIES A summary for study group by David Such Contents 1. 2. 3. 4. 5. Review of anatomy and physiology The craniosacral concept Palpating the cranial rhythm / involuntary motion Pattern testing Treatment 1. Review of anatomy & physiology A review of: Osteology of the cranium Meninges Dural partitions / membranes The ventricular system Cerebrospinal fluid Venous sinuses Osteology of the cranium The superior part of the cranium, which houses the brain, is called the cranial vault or the calvaria. The anterior aspect of the cranium is called the facial skeleton or viscerocranium Anterior view of the skull Lateral view of the skull Inferior view of the skull Meninges The meninges are three layers of membranes which surround the brain and SC 1. Dura mater – tough, thick external fibrous layer 2. Arachnoid mater – intermediate, delicate layer 3. Pia mater – innermost area, firmly attached to the surface of the brain Meninges: functions Protect the brain Form the supporting framework for arteries, veins and venous sinuses Form and enclose the subarachnoid space, which contains cerebrospinal fluid Meninges: the layers Meninges: a closer look • Dura mater – • Arachnoid mater – • Surrounds the brain, but does not enter the sulci or fissures Pia mater – • Thick, dense, fibrous membrane. Cranial DM has two parts: 1. Outer periosteal – formed by the periosteum covering the internal surface of the cranial bones, esp @ the sutures, cranial base and foramen magnum 2. Inner meningeal – continuous with spinal DM. It reflects away from the outer periosteal layer to form dural partitions / membranes – Between these two layers are the dural venous sinuses – Inn’d by CN V1-V3, C1-C3, CN IX & CN X Inner, delicate layer, which closely follows the contours of the brain including the deep sulci and fissures Between the pia and arachnoid mater is the only ‘real’ space – the subarachnoid space. This is cavity is filled with csf & cerebral blood vv and is supported by arachnoid trabeculae Meninges: innervation Innervation is from: 1. All three branches of CN V 2. CN X 3. Spinal nerves C1C3 4. & possibly from CN’s IX & XII Meninges: innervation Dural partitions / membranes The dural partitions project into the cranial cavity forming partial partitions between certain parts of the brain and providing support for other parts. Dural partitions Falx cerebri Tentorium cerebelli A horizontal shelf that separates the cerebellum from the cerebrum. Posteriorly it is attached to the occipital bone along the grooves for the transverse sinuses. Anteriorly it attaches to the posterior clinoid processes of the sphenoid bone Falx cerebelli A crescent shaped projection of meningeal DM that passes between the two cerebral hemispheres. Anteriorly it attaches to the frontal crest of the frontal bone and the crista galli of the ethmoid bone. Posteriorly it attaches and blends with the tentorium cerebelli Separates the two halves of the cerebellum. Superiorly it is attached to the tentorium cerebelli, whilst posteriorly it attaches to the internal occipital crest of the occiput Diaphragma sellae A small horizontal shelf that covers the hypophyseal fossa in the sella turcica of the sphenoid bone. The infundibilum passes through this membrane, connecting to the pituitary gland Dural partitions The ventricular system Ventricles are cavities within the brain that produce and contain csf. The ventricular system of the brain consists of two lateral ventricles and the midline third and fourth ventricles The ventricular system Each lateral ventricle opens through the interventricular foramina into the third ventricle. This is connected to the fourth ventricle by the cerebral aqueduct. Outflow of csf from here is by the median & lateral apertures and the central canal of the CSp SC The ventricular system Cerebrospinal fluid CSF is a clear, colourless, cell-free fluid that circulates through the ventricles & subarachnoid space that surrounds the brain and SC CSF: functions Mechanical protection: CSF protects the brain by providing a cushion against physical blows to the head. It is a shock-absorbing medium that adds buoyancy Chemical protection: CSF provides the optimum chemical environment for accurate neuronal signalling Nutrition: CSF allows the exchange of nutrients and waste between blood vv and neural tissue CSF: secretion & absorption CSF: secretion & absorption CSF is produced (at the rate of 400-500ml daily) by the choroidal epithelial cells of the choroid plexuses in the lateral, 3rd & 4th ventricles These consist of vascular fringes of pia mater covered by cuboidal epithelial cells CSF is reabsorbed by arachnoid villi (finger-like extensions of arachnoid that project into the dural venous sinuses) which clump together to form arachnoid granulations On the inner surface of cranial bones, small pits called granular fovea are produced by the pressure of the arachnoid granulations. They are most common on either side of the sagittal suture. CSF: circulation CSF: circulation 1. Formed in the choroid plexuses of the paired lateral ventricles 2. Flows into the third ventricle through the intervertebral formania 3. More CSF is added by the choroid plexus in the roof of the third ventricle 4. Flows through the cerebral aqueduct, passing through the midbrain, into the fourth ventricle 5. More CSF produced here as well 6. CSF then enters the subarachnoid space via the median and lateral apertures, and the SC by the central canal Venous sinuses Venous sinuses are endothelial-lined spaces between the outer periosteal and inner meningeal layers of the cranial dura mater. Large vv from the surface of the brain empty into these sinuses, which then drain into the IJVs Venous sinuses: the main ones 1. Superior sagittal sinus 2. Inferior sagittal sinus 3. Straight sinus 4. Transvers e sinus 5. Sigmoid sinus Venous sinuses: locations • Dural venous sinuses are endothelial-lined spaces between the outer periosteal and inner meningeal layers of the cranial dura mater. Lg vv from surface of the brain empty into these sinuses, which then drain into the IJVs • There are 5 main ones: 1. Sup sagittal sinus Sup border of falx cerebri; sagittal sulcus of frontal bone 2. Inf sagittal sinus Inf margin of falx cerebri 3. Straight sinus Continues posteriorly along the junction between the falx cerebri and tentorium cerebelli to reach the confluence of sinuses 4. Transverse sinus Passes laterally from the confluence of sinuses forming a groove in the occipital bones 5. Sigmoid sinus A continuation of the above, marks ‘s-shaped’ grooves in temporal & occipital bones of post cranial fossa – becomes IJV Venous sinuses: cavernous sinuses The cavernous sinuses are located on either side of the hypophyseal fossa They receive venous return from both cerebral veins (intracranial) and ophthalmic veins (extracranial) These connections provide pathways for infections to pass from extracranial sites into intracranial locations Venous sinuses: pterygoid plexus The pterygoid plexus of veins btwn the medial & lateral pterygoid mm is also connected to the cavernous sinus by small emissary veins This provides another route by which infection can spread into the cranial cavity from structures such as the teeth As there are no valves present in emissary veins, misplaced anaesthetic can also backflow into the cranial cavity 2. The craniosacral concept The craniosacral concept Primary respiratory mechanism Reciprocal tension membranes The craniosacral concept The craniosacral system is characterised by rhythmic, mobile activity which persists throughout life. It is distinctly different from the physiological motions related to breathing and CVS activity (Upledger & Vredevoogd, 1983, p.6) Sutherland observed mobile articulation at the sutures between the cranial bones He suggested that there existed (what he termed) a ‘primary respiratory mechanism’ which was the motive force for cranial motion He believed this mechanism was the result of a rhythmical action by the brain, which led to the repetitive dilation and contraction of cerebral ventricles – thereby promoting a ‘pumping’ of the cerebrospinal fluid He proposed that intracranial ligaments and fascia act to balance motion within the skull (Chaitow, 2005, p.4) Primary respiratory mechanism Becker describes this mechanism as a simple, basic, primary, rhythmic unit of function. We are totally dependent on this involuntary mechanism, which can be used as both a diagnostic tool, and a tool for ttt The five key elements that Sutherland proposed were: 1. 2. 3. 4. 5. Inherent motility of the CNS Fluctuation of cerebrospinal fluid Motility of cranial and spinal dural membranes Articular mobility of the cranial bones Involuntary sacral motion between the ilia Although it has been broken down into five components for teaching purposes, it remains one unit of function Reciprocal tension membranes The cranial term for the dural membranes They are the: Falx cerebri Falx cerebelli Tentorium cerebelli Diaphragma sellae They are continusuly under dynamic tension so that change in one requires adaptive change in another (Chaitow, 2005, p.4) Reciprocal tension membranes Greenam suggests that the continuation of the cranial meningeal dura mater with the spinal dura mater, and the subsequent att’s of this to the sacrum, provide a direct link between cranial and sacral motion The cranium produces a traction via the dura mater – which moves the sacrum rhythmically (Chaitow, 2005, p.6) 3. Palpating the cranial rhythm Flexion & extension phases Flexion & extension at the cranium Flexion & extension at the sacrum Hand holds Flexion & extension phases During the flexion phase of the craniosacral motion cycle, the whole body externally rotates and broadens During the extension phase the body internally rotates and seems to narrow slightly A complete cycle of the craniosacral rhythmic motion is composed of one FLX and one EXT phase The normal rate of the craniosacral rhythm is between 6-12 cycles per minute Flexion & extension at the cranium Transverse widening AP shortening Vertical shortening Transverse narrowing AP lengthening Vertical lengthening Flexion & extension at the sacrum Involuntary motion appears at the sacrum as a gentle rocking motion about a transverse axis located approx 1 inch anterior to the 2nd sacral segment Flexion Sacral apex moves anteriorly whilst the sacral base moves posteriorly (ie. counternutation) There is a flattening/flexion of the LSp lordosis Extension Sacral apex moves posteriorly whilst the sacral base moves anteriorly (ie. nutation) There is a hollowing/extension of the LSp lordosis Hand holds Cranium Ideally the second finger needs to be on the greater wing of the sphenoid and the fifth finger round the lateral margin of the occiput, so the cranial vault is being cradled (Chaitow, 2005, p. 40) Sacrum The sacrum should sit in the Op’s hand such that the apex is at the interthenar sulcus. The sacral spine should then lie between the third and fourth fingers (Upledger & Vredevoogd, 1983, p. 34) 4. Pattern testing Pattern testing takes place at the suture between the basilar part of the occiput and the sphenoid This is also know as the sphenobasilar synchondrosis/symphysis (SBS or SSB) – see note Patterns are grouped into: Physiological Non-physiological Physiological Flexion / extension Torsion (two opposing rotations) Side bending & rotation Asymmetries or distortions occuring at the SBS may result in altered tensions in the dural membranes. This will affect their ability to adapt and compensate The lesion is named for the direction toward which the cranial base moves with the greatest facility Flexion / extension Torsion Side bending & rotation Non-physiological Vertical displacement Lateral displacement Compression Vertical displacement Lateral displacement Compression 5. Treatment Balanced Membranous Tension CV4 Balanced Membranous Tension (BMT) ‘Balanced Tension’ “The most ‘neutral’ position possible under the influence of all the factors responsible for the existing pattern – all attendant tensions having been reduced to the absolute minimum” (Magoun, 1976) BMT Identify the strain pattern at the SBS (eg. left torsion with right side bending and vertical displacement) Find by palpation, the ‘middle’ point – position of ease Bring the fluid fluctuation to a ‘still point’ Re-palpate cranial rhythm to check for re-establishment of normal motion CV4 Palpate a couple of cycle of motion first Hand position for CV4 Thenar eminences medial to the occipitomastoid sutures Restrain rather than compress fluid fluctuation Gently ‘hold back’ during flexion phase, increasing this over approx 3 cycles Wait at the still point – don’t let go! Let the normal wave of involuntary motion resume – gradually easing off the restraint over approx 3 cycles Re-assess via cradle hold