If a passenger hits their head on the ceiling during turbulence, what injury could they sustain?

When a passenger hits their head on the ceiling during turbulence, the most likely injury they could sustain is a concussion. A concussion is a type of traumatic brain injury that occurs when there is a sudden impact to the head, causing the brain to move rapidly back and forth within the skull. This could certainly happen if a person strikes their head during sudden turbulence.

While back and neck injuries may occur due to the motion of the body during turbulence, the specific action of hitting one's head on the ceiling more directly relates to the impact of the head, making a concussion the most appropriate choice related to the scenario described.

The other options, such as ankle injuries or fractured skulls, are less likely to occur under these circumstances, as they do not directly result from the interaction of the head with a hard surface like the ceiling.