Any accident in which force is applied to the head has the potential to cause lasting brain damage. This includes not only accidents where the head is directly hit, but also any accident where the head is severely shaken, as the brain may become damaged from banging against the inside of the skull. Most types of brain damage accident involve a blow to the head, which may result in concussion. Although concussion itself may not cause lasting damage, it may indicate that a more serious injury has occurred, such as bleeding inside the brain. This may put pressure on the brain, which is known as "compression", which may block off blood vessels and lead to some of the brain being starved of oxygen. This may lead to death of brain tissue in some areas and permanent brain damage. The most common type of brain damage accident are motor vehicle crashes, although falls, work-related accidents, sports injuries and assault are all also significant causes in the U.S.