OMM Review — Osteopathy in the Cranial Field
Original OMM review notes for cranial mechanics, SBS motion, CRI, and strain patterns.
SBS Motion
The sphenobasilar synchondrosis (SBS) is the functional articulation between the sphenoid and occiput. In flexion, the sphenoid and occiput rotate so the base moves anterior/inferior and the apex moves posterior/superior. Extension is the opposite.
Flexion is sometimes paired with inhalation and external rotation of paired bones; extension with exhalation and internal rotation.
Cranial Rhythmic Impulse (CRI)
The CRI is a palpable, rhythmic waxing and waning of cranial motion. Rate and amplitude are assessed; asymmetry or decreased amplitude suggests somatic dysfunction. Treatment uses balanced ligamentous and membranous tension to restore ease.
Common Strain Patterns
| Pattern | Description |
|---|---|
| Torsion | Sphenoid and occiput rotate in opposite directions around parallel vertical axes |
| Side-bending rotation | Sphenoid side-bends and rotates; named by convexity |
| Vertical strain | Superior or inferior shear of sphenoid relative to occiput |
| Lateral strain | Horizontal translation/shear of sphenoid relative to occiput |
Clinical Applications
- Cranial OMT may support patients with headache, sinus congestion, or post-traumatic strain.
- Contraindications include active intracranial bleed, skull fracture, or acute hydrocephalus.
- Vault hold and CV4 are common cranial techniques; both are indirect and gentle.
Q: During cranial flexion, what is the SBS movement?
A: The SBS moves anterior/inferior at the base and posterior/superior at the apex, widening the cranial vault.
Q: What is the primary contraindication to cranial OMT?
A: Active intracranial pathology such as bleeding, fracture, or elevated intracranial pressure.