Fig. 15. Chiasmal trauma in closed-head injury in a 40-year-old motorcyclist with blindness and diabetes insipidus. Magnetic resonance images (TR, 1000 milliseconds; TE, 30 milliseconds). A. Coronal section shows a midsagittal tear and downward displacement of chiasm (small arrows). B. More posterior section shows an apparent rupture of the floor of the third ventricle (arrow).