<prompt> All of the following are pas of optic nerve exceptIntraorbital PaIntracanlicular PaCisternal SegmentIntra cavernal Pa  <response>: Answer- D. Intra cavernal PaOptic nerve is about 47-50 mm in length and can be divided into 4 pas :Intraocular pa l mmIntraorbital pa 30 mmIntracanalicular pa 6-9 mmIntracranial pa 10 mm 