Ossification of the Posterior Petroclinoid Dural Fold: A Cadaveric Study with Neurosurgical Significance

Abstract

Objectives The roof of the porus trigeminus, composed of the posterior petroclinoid dural fold, is an important landmark to the skull base surgeon. Ossification of the posterior petroclinoid dural fold is an anatomical variation rarely mentioned in the literature. Such ossification results in the trigeminal nerve traversing a bony foramen as it enters Meckel cave. The authors performed this study to better elucidate this anatomical variation. Design Fifteen adult cadaveric head halves were subjected to dissection of the middle cranial fossa. Microdissection techniques were used to examine the posterior petroclinoid dural folds. Skull base osteology was also studied in 71 dry human skulls with attention paid to the attachment point of the posterior petroclinoid dural folds at the trigeminal protuberances. Setting Cadaver laboratory Main Outcome Measures Measurements were made using a microcaliper. Digital images were made of the dissections. Results Completely ossified posterior petroclinoid folds were present in 20% of the specimens. Of the 142 dry skull sides examined, 9% had large trigeminal protuberances. Conclusions Based on this study, the posterior petroclinoid dural fold may completely ossify in adults that may lead to narrowing of the porus trigeminus and potential compression of the trigeminal nerve at the entrance to Meckel cave.

Bilateral Extensive Ossification of the Posterior Petroclinoid Ligament: An Anatomical Case Report and Literature Review

“…The arrangement of the dura mater within the petroclival, sellar, and parasellar regions is complex. [1][2][3] The clinoid processes are sites of attachment of important dural reflections described as petroclinoid and interclinoid dural folds, [4][5][6] commonly referred to as ligaments. 3,[7][8][9][10] On both sides, the free edge of the tentorium cerebelli reaches the petrous apex.…”

“…3,[7][8][9][10] On both sides, the free edge of the tentorium cerebelli reaches the petrous apex. Along its course, on either side of the sella turcica, it runs lateral to the posterior clinoid process and continues on to the anterior clinoid process, forming a dural reflection known as the anterior petroclinoid fold [4][5][6] or ligament 3,7-10 (►Fig. 1).…”

“…this part crosses below the free border of the tentorial notch of the tentorium cerebelli. This rounded ridge of the dura mater is referred to as the posterior petroclinoid fold [4][5][6] or ligament 3,7-10 (►Fig. 1).…”

“…1). Furthermore, the posterior petroclinoid ligament forms the roof of the porus trigeminus, which is entrance of the trigeminal nerve to Meckel's cave, 4,8,9,11 as well the roof of the petroclival venous confluence. 1,12 Ossifications of petroclinoid ligaments are rarely described in anatomical literature, 7,8 with most descriptions of such findings based on radiologic studies.…”

“…1,12 Ossifications of petroclinoid ligaments are rarely described in anatomical literature, 7,8 with most descriptions of such findings based on radiologic studies. [13][14][15][16] So far, only Kimball et al, 4 Perumal and Gayathri, 11 and Rusu et al 17 have provided observations of ossification of the posterior petroclinoid dural folds on wet specimens. However, these authors focused mainly on the significance of a completely ossified posterior petroclinoid dural fold as a factor potentially relating to trigeminal neuralgia.…”