Describe the axis of a lateral strain.

• A. Occiput and Sphenoid move in the same directions about their vertical axes.
• B. Occiput and Sphenoid move in opposite directions about their vertical axes.
• C. They move about transverse axes in the same direction.
• D. They rotate about the anteroposterior axis in opposite directions.

Answer: (A)

Lateral strain is a cranial strain pattern where the sphenoid and occiput rotate about vertical axes in the same direction. This parallel rotation causes the SBS to shift side to side, producing a lateral displacement of the cranial contents without opposing movement between the two bones. In this view, the key feature is that both bones move together in the same sense around vertical axes, rather than opposite directions (which would describe torsion) or rotations about other axes. This shared rotation creates the lateral shift characteristic of lateral strain, distinguishing it from other cranial strain patterns.