Concomitant completely ossified trigeminal pore and Dorello's canal

Area of Science:

• Neuroanatomy
• Radiology
• Skull Base Anatomy

Background:

• The trigeminal nerve (cranial nerve V) and abducens nerve (cranial nerve VI) typically traverse the middle cranial fossa.
• Their pathways involve structures like the tentorial border and Grüber's petrosphenoidal ligament, leading into Dorello's canal.

Observation:

• A rare unilateral association of anatomical variants was identified in a 56-year-old male patient's brain computed tomography angiography.
• The left side exhibited an ossified tentorial border forming a tentorial bar, completely ossifying the trigeminal pore.
• Additionally, an ossified petrosphenoidal ligament was found on the left, resulting in a completely ossified Dorello's canal.

Findings:

• The left tentorial bar measured 1.96 cm, causing complete ossification of the trigeminal pore.
• The left petrosphenoidal ligament ossification led to a completely ossified Dorello's canal.
• The right side presented a 2.9 mm clinoid bar extending between the anterior and posterior clinoid processes.

Implications:

• Ossified bars and ligaments, though uncommon, are significant anatomical variations.
• Documentation in computed tomography is crucial for patients presenting with trigeminal neuralgia and abducens nerve palsy.
• Understanding these variations aids in accurate diagnosis and surgical planning in skull base pathologies.