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Updated: Aug 12, 2025
Author Spotlight: Three-Dimensional Cephalometric Landmark Annotation Demonstration on Human Cone Beam Computed Tomography Scans
Published on: September 8, 2023
The "Crista Ovale": A Reliable Anatomical Landmark in Transorbital Endoscopic Approaches to the Middle Cranial Fossa
Juan C Yanez-Siller1,2, Raywat Noiphithak3,4, Rafael Martinez-Perez3,5
1Department of Otolaryngology-Head and Neck Surgery, University of Missouri-Columbia, Columbia, Missouri, USA.
Background:
Transorbital endoscopic approaches (TOEAs) have emerged as adjunct and alternatives for accessing the middle cranial fossa (MCF). Nuances of the skull base anatomy from a ventral transorbital endoscopic viewpoint remain to be fully described.
Objective:
To assess the anatomy of the "crista ovale" (COv), described transcranially as the midsubtemporal ridge (MSR), from a ventral transorbital perspective and evaluate its role as a landmark in TOEA to the MCF.
Methods:
Lateral TOEAs to the MCF were performed in 20 adult cadaveric heads (40 sides). The presence of the COv/MSR was evaluated under endoscopic visualization. Anatomic relationships between COv/MSR and surrounding structures were assessed. The presence of COv/MSR was also examined in 30 cadaveric head computed tomography (CT) scans (60 sides).
Results:
The COv/MSR was identified in 98% (39/40) of sides at the MCF, as 1 of 4 major configurations. The COv/MSR was found anterolateral to the foramen ovale and foramen spinosum (mean distance: 9.2 ± SD 2.4 mm and 12.3 ± SD 2.6 mm, respectively) directly anterior or anteromedial to the petrous apex (mean distance: 26.2 ± SD 2.6 mm) and at a mean 47.6 ± SD 4.7 mm from the approach's surgical portal. It was recognized in 95% (57/60) of CT scans.
Conclusion:
The COv/MSR can be readily identified during TOEA to the MCF and on CT. It serves as a reliable landmark to localize the foramen ovale, foramen spinosum, and petrous apex. Further studies may confirm its surgical significance in transorbital endoscopic procedures.
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