Microsurgical anatomy of sympathetic fibres running inside the cavernous sinus

A microanatomical study has been designed to obtain data concerning the pattern of organization of the sympathetic fibres running within the cavernous sinus. The course of the sympathetic fibres has been examined in 60 fresh specimens of parasellar region from autopsy cadavers. The sympathetic nerve or nerves running with the carotid artery provide a multitude of thin branches at irregular intervals along its course, but the largest residual usually joins the 6th cranial nerve and leaves it to join the first division of the 5th. Despite other anatomical descriptions, we have found a direct connection with the ophthalmic branch of the trigeminal nerve in 10% of specimens. We report also an unrecognized parasellar syndrome characterized by Horner's syndrome and ipsilateral sensory disturbances over the distribution of the ophthalmic branch of trigeminal nerve, due to a traumatic carotid-cavernous fistula. We think that the anatomical data, together with the clinical findings of this syndrome, could explain the role of the sympathetic fibres within the cavernous sinus.