The brain injury is due to movements of the brain in relation to the skull or distortions of the skull.
· The flax cerebri and tentorium divide the cranial cavity into three communicating compartments and have a partly restraining effect on brain movements.
· Injuries like contusion and lacerations of the brain seen in vehicular accidents and falls from heights are caused by the application of violence to the head and may occur with or without external injury to the scalp and fracture of the skull.
· injuries may be seen superficially anywhere on the surface of the brain, though the commonest site is the outer surface of the parietal and temporal lobes or deep within the brain substance, and are associated with hemorrhages limited in small areas or multiple hemorrhages diffused largely within the brain tissues. They are also associated with disturbances of cerebrospinal fluid circulation.
· These injuries, also known as coup lesions, are commonly found under the site of application of the blow, but are also sometimes found particularly during autopsy on the surface of the brain diagonally opposite the site of impact, and are called countercoup injuries.
· Coup injuries are most commonly found on the frontal lobes and near the tips of the temporal and frontal poles, rarely on the occipital poles. They are usually severe injuries.
(Ref: Modi’s Medical Jurisprudence 25th edition)