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Spinal nerve and meninges
SBS motion
What is the Primary Respiratory Mechanism (PRM), foundation of Cranial Osteopathy ?

The cranial rhythmic impulse (CRI) refers to the palpatory sensation of the widening and narrowing of the skull.

  • Normal rate: 8–14 times per minute

  • A result of the PRM

The PRM is composed of five elements :

  1. Inherent motility of the brain and spinal cord

    • Brain and spinal cord have an inherent wave-like motion.

    • Described as coiling and uncoiling of the central nervous system (CNS).

  2. Fluctuations of the cerebrospinal fluid (CSF): volume of CSF changes in relation to the cranial rhythmic impulse (CRI).

  3. Mobility of the intracranial and intraspinal membranes

    • The meninges surround the CNS and are made up of the dura, arachnoid, and pia mater.

    • A continuous connection is present from the foramen magnum to the cervical vertebrae and second sacral segment.

    • These membranes move due to the inherent motility of the brain and spinal cord and fluctuations of the CSF.

    • Motion of these membranes causes the cranial bones and sacrum

       to move in relation to one another.

  4. Articular mobility of cranial bones

    • Although cranial sutures fuse shortly after birth, they contain small motions that cannot be felt individually.

    • An amalgamation of the cranial bones and multiple sutures allow for palpable motion.

  5. Involuntary mobility of the sacrum between the ilia

    • The dural connection between the cranium and S2 of the vertebral column causes sacral movement.

    • This dural connection is termed the reciprocal tension membrane (RTM).

    • The bones move in rhythm with the motion of the shifting tensions of the RTM.

The primary physiologic motion is between the articulation of the sphenoid and the occiput called the sphenobasilar synchondrosis (SBS).​ It moves in a biphasic cycle (flexion and extension) in response to the pull of the reciprocal tension membrane and fluctuations of the CSF.​

A woman playing golf

ACUTE PAIN

Barista at Work

CHRONIC PAIN

Hotel Room

WORK INJURY

On the Edge of a Cliff

SPORTS INJURY

Balanced Rocks

MAINTENANCE

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