To discuss the pathology and pathogenesis of extradural, subdural and subarachnoid haemorrhages. To discuss the pathology of major degenerative diseases of the brain with particular reference to Alzheimer's disease and Parkinson's disease. To discuss the pathology and pathogenesis of multiple sclerosis. Note the structure and position of the extensions of the lateral ventricles. Parenchymal injuries include concussion, contusion, laceration and white matter injury.
Contusions occur where the brain hits the bones of the skull following a decelerating injury.
Contusions at the site of the initial impact represent a coup injury, those on the opposite site, a contre-coup injury. The contre-coup injury is often more extensive. The common sites of injury are the crests of gyri at the tips of the temporal lobes, the inferior frontal surfaces and the occipital poles. Early lesions show oedema and haemorrhage. Histologically, the lesions show gliosis and macrophages containing haemosiderin.