In head<unk> , a<unk><unk>  occurs under the site of impact with an object, and a<unk><unk>  occurs on the side opposite the area that was impacted.<unk>  and<unk><unk>  is associated with cerebral contusions.<unk>  and<unk> <unk> es can occur individually or together.  When a moving object impacts the stationary head,<unk> <unk> es are typical, 
while<unk> <unk> es are usually produced when the moving head strikes a stationary object.
In a<unk><unk> , the head stops abruptly and the brain collides with the inside of the skull.<unk>  and<unk> <unk> es are considered focal brain<unk> es, those that occur in a particular spot in the brain, as opposed to diffuse, which would occur over a more widespread area.
The mechanism for the<unk> es, especially<unk> <unk> es, is a subject of much debate.  It is likely that inertia is involved in the<unk> es, e.g. when the brain keeps moving after the skull is stopped by a fixed object or when the brain remains still after the skull is accelerated by an impact with a moving object.  Alternately, movement of cerebrospinal fluid following a trauma may play a role in the<unk> .
Coup contrecoup injury
Suspension trauma
Blast injury
Occult fracture
Maisonneuve fracture
Burst fracture
Disc slip
Cerebral contusion