Multifocal cerebellar granular layer necrosis in traumatically head-injured lambs

In a blunt, nonmissile, head impact model of traumatic brain injury in 4-5-week-old Merino lambs, multiple foci of internal granular layer necrosis were found in all 10 impacted animals. This lesion has not previously been reported after human or animal head injury. Temporal lobe impact contusions, predominantly microscopic (8/10) and contralateral contusions (2/10), parenchymal (10/10) and subarachnoid (10/10) hemorrhage, and widely distributed axonal injury were also observed. Although the precise pathogenesis of this focal granule cell necrosis and often attendant red cell change in Purkinje cells was unclear, an ischemic etiology due to trauma-related vascular damage is postulated.