As the brain moves forward and backward, white matter pathways are strained and tear. Certain parts of the brain also strike resistant parts of the skull and brain structures, such as the falx and anterior parts of the skull. The rotational injury produces mechanical trauma of the white matter and blood vessels within the white matter. Damaged blood vessels hemorrhage and this compresses the surrounding brain tissue. When the brain strikes the interior surface of the skull, this may also produce contusion and hemorrhage.
Mechanical trauma includes diffuse axonal injury and contusions.