DISPLACEMENT AND HERNIATION OF THE HIPPOCAMPAL GYRUS THROUGH THE INCISURA TENTORII

Abstract

It has long been recognized that a mass lesion within the cranial cavity often produces disturbances of function which cannot be ascribed to the actual site of the growth. 1 One of the causes of distant or false localizing signs of an expanding intracranial lesion is the shift of the brain substance to produce herniations about certain partially fixed, extracerebral structures and into certain potential spaces within the skull cavity. 2 Thus, a representative herniation, the cerebellar pressure has been understood to have considerable clinical significance ever since it was described by Alquier, in 1905. 3 Similarly, after Adolf Meyer's description and illustration of herniation of the hippocampal structures into the incisura tentorii, 4 it has become evident that this dislocation of cerebral substance, called by van Gehuchten 5 the temporal pressure cone, is a consistent producer of secondary functional derangements. Evidence has accumulated to show that such a