K, The lower maxilla has been displaced downward. The clival window and vertebral arteries can be seen through the exposure. L, Enlarged view of the clival opening. M, The maxilla has been split vertically in the midline and the halves reflected laterally, allowing the clival opening to be extended upward. N, Enlarged view of the clival exposure. The right AICA passes behind the right abducens nerve and the left AICA passes in front of the left abducens nerve. (Images courtesy of AL Rhoton, Jr.)