Which terms describe the motions involved in SBS side bending?

• A. Clockwise and counterclockwise motions
• B. Linear translation
• C. Pure rotation
• D. No motion

Answer: (A)

SBS side bending is a rotation-dominated movement. The sphenoid and occiput move about an axis at the sphenobasilar junction, and when you observe the motion from a suitable vantage point, the rotation direction can be described as either clockwise or counterclockwise. This rotational description captures the way the bones twist together to produce the side-bend, rather than a simple straight shift (linear translation) or pure rotation alone. So the best way to express SBS side-bending motion is by its direction of rotation—clockwise or counterclockwise.