Anatomy of the clinoidal region with special emphasis on the caroticoclinoid foramen and interclinoid osseous bridge in a recent Turkish population

In this study we present the incidence of caroticoclinoid foramen and interclinoid osseous bridge and some topographic aspects regarding the clinoidal internal carotid artery (ICA) in a recent Turkish population to provide a guide for neurosurgeons in any surgical approach, especially to the cavernous sinus. One hundred nineteen adult dry skulls and 52 adult cadaveric heads were used for this purpose. Caroticoclinoid foramen and the interclinoid osseous bridge were divided into three types based on the classification of Keyers [13]. Caroticoclinoid foramen was observed in 35.67% of the specimens, unilaterally in 23.98%, and bilaterally in 11.69%. The complete-type caroticoclinoid foramen was observed in 4.09% of the specimens, the contact type in 4.68%, and the incomplete type in 14.91%. Transverse diameter of the foramen was 5.32±0.52 mm for the incomplete type. The incidence of interclinoid osseous bridge was 8.18%. The middle clinoid process was prominent in 15.12% of cases and rudimental in 13.23%. The mean distance between the proximal and distal dural rings of the clinoidal ICA was 4.51±0.44 mm, and mean diameter of the distal ring was 5.25±0.59 mm. Right-left differences were assessed for each parameter, and populational differences are discussed.