Connections of sympathetic fibres inside the cavernous sinus: a microanatomical study.

A microanatomical study has been designed to investigate the pattern of arrangement of the sympathetic fibres inside the cavernous sinus. The course of these fibres has been examined in 60 fresh specimens of parasellar region from autopsy cadavers. Apart from the thin branches arising at different intervals along its course, the sympathetic plexus of the carotid artery gives rise to a large division that usually joins the abducens nerve and leaves it to combine with the ophthalmic branch of the fifth. In 10% of specimens we have found a direct connection between sympathetic fibres and the ophthalmic branch of the trigeminal nerve. We did not recognise similar connections with oculomotor and trochlear nerves.