Lecture on Cranial Strain Patterns

Overview

• Focus on cranial strain patterns involving the sphenoid and occiput.
• Palpation: Greater wings of the sphenoid and the squama of the occiput.
• Use of hand representations for illustrating cranial motion.

Normal Motions

Flexion and Extension

• Flexion:
  • Sphenoid rotates anteriorly around a transverse axis at its base.
  • Occiput rotates posteriorly around a transverse axis above the foramen magnum.
  • Hands: Fingers move apart and inferiorly.
• Extension:
  • Sphenoid and occiput close up and may slightly exaggerate in the opposite direction.
  • Hands: Fingers come together and move superiorly.

Physiologic Strain Patterns

Exaggerated Flexion

• Normal or exaggerated flexion; sphenoid and occiput do not fully close in extension.
• Hands: Fingers open during flexion, don't close during extension.

Exaggerated Extension

• Restriction during flexion; cranium doesn’t open up fully.
• Hands: Limited opening during flexion; enhanced extension.

Side Bending Rotation

• Mismatched flexion and extension on either side.
• Rotation:
  • Sphenoid and occiput rotate in opposite directions around vertical axes.
• Naming: Based on which side becomes convex (e.g., right side bending rotation).

Torsion

• Twisting motion: Occiput and sphenoid rotate in opposite directions.
• Single anterior-posterior axis through the body of the sphenoid and foramen magnum.
• Naming: Based on superior movement of the greater wing of the sphenoid (e.g., right torsion).

Pathologic Strain Patterns

Lateral Strain

• Sphenoid and occiput rotate in the same direction around vertical axes.
• Palpation: Leads to a shearing force, forming a parallelogram (e.g., right lateral strain).
• Rotatory Force: Parallelogram shifts.

Vertical Strain

• Sphenoid and occiput rotate in the same direction around transverse axes.
• Superior Vertical Strain: Sphenoid moves superiorly relative to the occiput.
  • Hands: Wrists shift superiorly.
• Inferior Vertical Strain: Sphenoid moves inferiorly.
  • Hands: Wrists represent downward movement.

Compression

• Restricted motion at the sphenobasilar symphysis in all directions.
• Palpation: Feels like a heavy, stagnant cranium ("bowling ball" feeling).

Conclusion

• Comprehensive discussion on recognizing and palpating different cranial strain patterns.