There are two types of cerebral contusions: coup and contrecoup injuries. In coup injuries, an impact directly on the side of the skull causes bruising on that side of the brain. In contrecoup injuries, bruising occurs when the brain bounces against the skull from an impact on the opposite side of the head.
Contrecoup injuries are typically more severe, as the bouncing against the skull can cause blood vessels to twist or tear more significantly than bruising from a direct impact. Other brain matter can become twisted and torn as well, and this can result in swelling or bleeding.
Contusions can lead to a condition where blood pools on the brain, known as a hematoma, which can cause permanent brain damage or even death. Because severe cerebral contusions tend to be found in the temporal and frontal lobes of the brain, issues frequently arise with reasoning skills, emotional stability, attention span and memory.