Is it the impact or the sudden jolt after?
 

So I was wondering if for example you were to suffer impact from a moving object such as the fists from another person. Does concussion occur from the actual energy from the punch to the bones or from the sudden jerk/rotation afterwards? I read it could happen solely by the energy transmitted from the punch to the bone, is this true? And if so, does it then require so much energy that the bones will likely break before a concussion happens? This is technically speaking, if it were to happen without any head movement caused by the impacting force, as a real case scenario will likely result in head movement from such a force.

Why I ask this is because I accidentally was struck by a small impacting force on one of my cheekbones, luckily enough, there wasn't really any jolt/jerk/rotation, all that really happened is me ending up with feeling a bit sore. So is it the acceleration/deceleration after the punch that's reason for concern, or the actual impacting force. Greater force = Greater jerk too I guess, so there is a connection, but I believe the force wasn't significant enough to cause any real sudden movements of the head.

So which one of the two is the trigger for a potential concussion? The sudden movement or the actual energy from the punch?

It is the energy of the impact or more accurately, the acceleration or deceleration of the brain within the skull. It is the brain impacting the inside of the skull that is the trauma. The skull does not have to move very much for the brain to be subjected to trauma. It all depends on the difference between the rate of acceleration/deceleration of the skull versus the acceleration/deceleration of the brain within the skull.

Think of it like driving in congested traffic. The car 1 in front is the skull. Car 2 following is the brain. If the front car slows faster than car 2 slows, car 2 will impact car 1, even if both are still moving. It is the differential between the two speeds or rate of deceleration that causes the impact.

The question is. What is the minimum force required to cause concussion trauma ? Even the experts do not know the answer. Some think it is 60 G's meaning your head would feel like it had a 180 pound brain banging into the side of the skull. Others think it is much higher. But, the brain has fluid surrounding it that allows for some of the impacting force to happen without causing any trauma.

In your case, it does not sound like there were forces strong enough to be concerned.