Which trauma is associated with the number 1 in the sequence?

• A. Inferior vertical strain
• B. Right lateral strain
• C. Left lateral strain
• D. Left sidebending rotation

Answer: (C)

In cranial evaluation, the patterns of strain reflect how the sphenobasilar synchondrosis and surrounding bones respond to trauma. A left lateral strain means the pair of bones at the SBS shift laterally to the left, producing a unilateral, side-to-side displacement along the left-right axis. In the trauma sequence described in this material, the first trauma pattern that appears is the left lateral strain, making it the best match for the initial event. The other options describe different mechanical patterns: an inferior vertical strain moves along the vertical axis, a right lateral strain would be a lateral shift to the right, and a left sidebending-rotation combines bending to the left with rotation, which is a distinct pattern from a pure lateral translation. So the first trauma in the sequence aligns with a left lateral strain.