Transtentorial uncal herniation compresses which cranial nerve -: (A) III, (B) IV, (C) VI, (D) VII
Answer is A. Ans. is 'a' i.e., III * Uncal herniation can compress the third nerve, compromising the parasympathetic supply to the pupil, so that unopposed sympathetic activity produces an enlarged and sluggish pupil, which then, if the compression continues, becomes fixed and dilated.