Large medial temporal pressure cone (herniation): In this specimen the brain stem has been sectioned, exposing the junction of pons and midbrain. The herniation is unusual in that most of the tissue which has been displaced over the tentorial margin is medial temporal lobe tissue lying posterior to the uncus. There is a massive hemorrhage in the right cerebral hemisphere that has caused the herniation. The secondary effects of the herniation are distortion of the brain stem and focal brain stem hemorrhages.