Why a man loses consciousness when he was hit on the head from behind?

Firstly, the movie is posing. And, secondly, a blow to the head, at least in the forehead, though the crown is able to lead to loss of consciousness. Develops from a sudden decline in blood pressure, plus brain disorders. Loss of consciousness, the first reliable symptom of traumatic brain injury, which identifies a neurologist. Further, trying to determine the length of time of loss of consciousness, which has already been determined by the severity and form of cranial injury, from concussion to brain injury. This is a very important symptom of traumatic brain injury, which may be present initially. If loss of consciousness develops late, it will be extremely bad symptom that indicates a compression of the brain.
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