Mechanisms in cerebral lesions in trauma to high cervical portion of the vertebral artery--rotation injury.

Three cases have been described illustrating the mechanisms and effects of lesions from acute rotation injury to the vertebral artery. These indicate that the portion of artery at risk is in the C1 to C2 region, where stretching and shearing strains can produce intramural dissection and haemorrhage. Such changes can radically alter flow to produce acute arterial obliteration or later cerebral embolism. Such alteration can also produce a change in relationships between artery and surrounding structures and thus cause intermittent occlusion of a vertebral artery upon cervical rotation.