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Understanding Traumatic Brain Injury

Breathing, blood flow, and movement are all controlled by the brain. The brain also allows you to think, handle emotions, and make judgments. After an injury, certain parts of the brain (or the links between these parts) may stop working. Some mental or physical skills may be lost. The first symptom of brain injury is loss of consciousness (LOC). How long LOC lasts depends on how severe the injury is. Long-term effects of brain injury can include poor concentration, which can affect learning. Other effects can include changes in insight, motivation, and ability to stay focused on tasks. Physical impairments may also occur, including changes in vision and hearing, as well as balance problems.

Outline of head with brain inside. Head is moving backwards. Arrow shows brain moving backward inside skull.
The brain rebounds  from the impact. As a result, the brain may hit the opposite side of the skull or twist on the brain stem.

Outline of head with brain inside. Head is impacting windshield in car. Arrow shows brain moving forward inside skull.
The brain strikes the skull. This may happen if the head hits a hard surface or if a person is severely shaken or jerked.

How Injury Happens

The skull does not have to be harmed for the brain to be injured. Injury can occur when the brain strikes the skull. In many cases, the brain rebounds from the first impact and hits the opposite side of the skull. Sometimes the brain twists on the brain stem.

Types of Damage

When the brain strikes the skull or twists on the brain stem, brain tissue tears. This injury may then cause a second type of damage, such as bleeding or swelling in the brain. Health care providers try to control the second type of damage to help limit long-term problems.

Nerve cell showing torn nerve fiber.

Outline of head with brain inside skull bone. Hematoma is building up between skull and brain, pressing on brain.

Outline of head with brain inside skull bone. Arrows show brain swelling out and pressing against inside of skull.


If nerve fibers in the brain tissue tear, signals can’t pass between the brain and body. Lost signals mean lost skills or body functions.


A torn blood vessel may leak into nearby tissue. This kills brain cells and can lead to a buildup of blood (hematoma). If this blood presses on the brain, it can cut off blood to other cells. These cells also die.


The brain has almost no room to expand inside the skull. If the brain swells, it may press against the skull. As the pressure increases, the brain begins to stop working.

Author: StayWell Custom Communications
Last Annual Review Date: 5/15/2011
Copyright © The StayWell Company, LLC. except where otherwise noted.
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