An unusual finding of the Porus trigeminus: Case report with histological findings.

Many anatomical variants can potentially contribute to trigeminal neuralgia. These include compression by the superior cerebellar artery and less commonly, bony compression near the trigeminal cave. Herein, we report the gross and histological findings of a cadaveric specimen found to have a bony roof of the trigeminal cave. During the routine dissection of a male cadaver, an unusual finding of the skull base was observed. Palpation over the porus trigeminus identified a completely ossified roof. The bony spicule was 1.22 cm long and 0.76 mm wide. The trigeminal nerve was noted to have an indented region just below its contact with the ossified roof of the porus trigeminus. No frank nerve degeneration was noted with histological analysis. Normal mature bone tissue was noted surrounded by a sheath of dura mater. Future radiographic research is needed to better elucidate if ossification of the roof of the trigeminal cave is related to clinical symptoms of trigeminal neuralgia (TN). However, physicians should be cognizant of radiographic ossification of the trigeminal cave as a potential cause of TN.