Uncal herniation
Posted by dkwinter

Classic sign:

  • Ipsilateral pupillary dilation associated with contralateral hemiparesis


  • Supratentorial mass effect (e.g. epidural hematoma from a MMA lesion due to temporal bone #)
  • Herniation of the uncus of the temporal lobe through the tentorial hiatus pushing against the midbrain affecting the reticular system (affecting GCS), the corticospinal tract in the midbrain (contralateral hemiparesis), and the nearby oculomotor nerve (parasympathetic surface fiber impairment causes ipsilateral blown pupil)