Craniosacral – The Sphenobasilar (SBS) Mechanism, Axes & Quadrants

The sphenobasilar mechanism includes the sphenoid bone, the occipital bone, and the sphenobasilar synchondrosis (SBS). The SBS is the joint between the sphenoid and occiput. It starts as a synchondrosis. Eventually, usually between ages 18 and 25, the cartilaginous place is ossified, creating a “sphenocciput.”

The center of this mechanism cradles the pituitary in the cavernous sinus of the venous sinuses. Thus, the pumping action supports the CNS centers for regulation and the cavernous sinus.

Overview of Axes

The craniosacral motility is primarily seen as tidal motion that ebb and flow through flexion and extension. You can read more about the details of that in this other post.

There are three pairs of axes:

• Transverse axes
• Anterior to Posterior axes (A/P)
• Verticle axes

Axes and SBS Patterns

• Transverse axes allow the spenobasilar mechanism flex and extend. When the spenoid and occiput are out of sync, the transverse axis allow superior and vertical strain patterns. As well, the ethmoid and vomer rotate on transverse axes.
• Anterior to Posterior (A/P) axis allow the sphenobasilar mechanism to torsion and rotate. Torsion occurs when the spenoid and occiput rotate in different directions on the A/P axis. Rotation generally occurs when at the far end of sidebending patterns.
• Verticle axes allow the spenobasilar mechanism to lateral strain and sidebend. Lateral strain occurs when the spenoid and occiput rotate in the same dorection on the vertical axes. Sidebending occurs when the sphenoid and occiput rotate in different direction on the vertical axes.
• The SBS has combined patterns such as vertical strain with torstion.
• In addition, the SBS has non-axial motions i.e. shearing.

Craniosacral and the Sphenobasilar Mechanism

The word “craniosacral” comes from the direct structural relationship between the sphenobasilar mechanism and the sacrum. The dural tube provides a complex pulley system between the cranium and sacrum.

Although analysis varies a bit from one approach to another, this diagram conveys the basic idea. As the occiput flexes and extends, the sacrum nutates (nods) and counter-nutates. As restrictions create variances in the cranial motility, the sacral motility is altered. In addition, these restrictions and alterations have consequences throughout the pelvis and the entire somatic system.

Governing Bones

The sphenoid governs the movements of the frontal bone, ethmoid, and face. On the other hand, the occiput governs the parietal and temporal bones.

This understanding can be critical in assessing and releasing restrictions in the cranial structure.

Quadrant Analysis

Quadrant analysis allows the biomechanical craniosacral practitioner to assess and resolve restrictions and altered patterns by smaller sections of the cranial system. It divides the cranium into bones that are governed by the sphenoid or the occiput. Also, it divides those anterior and posterior sections into left and right hemispheres.

This process of quadrant analysis becomes essential in resolving CranioMuscular patterns by quadrant as well. For the craniostructural therapist, quadrant analysis in combination with sutural analysis targets somatic governors. More simply put, this process allows the practitioner to connect cranial restrictions to musculoskeletal patterns.

Cranio Cradle Cup

This mug has classic, colorful illustrations of the craniosacral system and vault hold #3. It makes a great gift and conversation piece.