[A case of closed head injury with diffuse axonal injury, and oculomotor nerve avulsion and midbrain infarction].

We report an autopsy case of 66-year-old woman with closed head injury due to a fall from stairs. She had recovered after a half day period of coma following the fall. Severe right peripheral oculomotor nerve palsy was noted from the beginning. MRI demonstrated lesions in the corpus callosum and right midbrain. She had died of suffocation due to sputum impaction after 50 hours after the fall. Autopsy examination revealed traumatic subarachnoidal hemorrhage, partial tearing and petechial hemorrhage of the corpus callosum, and many axonal retraction balls scattered in the cerebral white matter. Avulsion of the right oculomotor nerve root and fresh midbrain infarct with hemorrhage in the territory of right paramedian artery were observed. Axonal retraction balls were densely distributed in the periphery of midbrain infarct. The distribution pattern of axonal retraction balls in the cerebrum was similar to that of damage due to shear strain in Holbourn's gelatin model of closed head injury. The midbrain infarct and oculomotor nerve avulsion may be due to both mechanical and ischemic damage during and after the fall. All of the lesions described above may be closely related to the rotatory force from the right forehead.