Blood distribution in the facial nerve in temporal bones acquired from cases with subarachnoid hemorrhage.

The objectives of this study, conducted in eight temporal bones from five autopsied cases of subarachnoid hemorrhage, were to delineate the communication between the cerebrospinal fluid space and each space of the epineurium, perineurium, and area surrounding the nerve fibers in the facial nerve and to identify the site of hypertonic diuretic solution infusion most likely to decrease the facial nerve swelling at the initial stage of facial palsy. In all eight specimens, blood cells had directly entered into each space from the labyrinthine segment of the facial nerve. The subarachnoid space extended to the first genu of the nerve. The genu, which is the site of the initial lesion in Bell's palsy, is concluded to be the most effective site of intracanal decompression of the facial nerve with hypertonic diuretic solution.