A big stone fell on my head from a building? the doctor said me that there was a little hameorage but no need of operations?

Ask Dr on concussion: Everybody in the world gets blows to the head once in a while. Rarely are they concussions. Likewise, everybody in the world gets blows to the abdomen sometimes, but rarely are they internal organ bruising injuries. That's because a blow is a vague word covering all severities. Concussion means there is detectable injury to the brain's functioning, even if nothing unusual is visible on brain scan.