Based on the scenario described, the most likely type of movement that has caused Layla's spinal injury is compression.
In a car accident where an individual is thrown forward due to a sudden stop, the forces involved can lead to vertebrae being compressed against each other, potentially causing injuries to the spinal column. While overextension, flexion, and distraction can also cause spinal injuries, the mechanism of being thrust forward in a collision typically results in a compressive force on the spine.