calmwaters,

No, there was not enough force from just one pothole to cause a concussion. There is also not enough force from riding a bike over a pothole either.

The 'hitting the inner wall of the skull' idea is not sound until the forces are much higher than anything without an impact can cause. The only time the brain moves separate from the skull is during a rotational motion. Otherwise, the brain and thin layer of surrounding fluid have very similar densities so they will move together. If there is enough force in the impact, then a shock wave will transit the brain matter.

The two issues that can cause symptoms are stress to the neck and anxiety/startle response. These would be more of a problem to someone with a PCS history.