Concomitant completely ossified trigeminal pore and Dorello's canal

Abstract

Commonly, the trigeminal and abducens nerve course to the middle cranial fossa, beneath the tentorial border (posterior petroclinoid dural ligament) and, respectively, beneath Grüber's petrosphenoidal ligament, in Dorello's canal. It is hereby reported a rare unilateral association of anatomic variants which was found when the brain computed tomography angiography of a 56-year-old male patient was observed. On the left side, the tentorial border was ossified above the petrous apex, resulting in a tentorial bar 1.96 cm long that transformed the trigeminal pore into a completely ossified one. On that side was also found an ossified petrosphenoidal ligament determining a completely ossified Dorello's canal. On the opposite side a 2.9 mm long clinoid bar extended from the posterior clinoid process to the anterior one. Although these bars are not common in humans they should be documented in computed tomography in cases with associated trigeminal neuralgia and abducens nerve palsy.

Keywords: abducens nerve; petrous apex; trigeminal nerve; trigeminal neuralgia.