Investigation of the relationship between the cephalic index and the tentorium cerebelli: A retrospective study

The cerebellar tentorium, composed of 2 laminae of dura mater, is an essential structure that separates the posterior and middle cerebral fossae. As it has a dural sinus within its 2 laminae, it carries significant risk potential. Cranium shape may affect its morphological properties. The cephalic index (CI) can easily describe a ratio of the length and width of the cranium. People may have different CI values individually, or some populations have a typical cranium shape that gives a clue for the CI. The aim of the present study was to investigate the morphometric properties of the cerebellar tentorium related to CI groups. A total of 594 participants' (304 women and 290 men) computed tomographic angiography image series were included in the presented study, retrospectively. We evaluated cerebellar tentorium's morphometric properties, its length, and its angle according to the McRae line, and compared these measurements in relation to CI. All morphometric evaluations were completed using free licensed Horos Software v.3.3.6. According to our results, morphometric properties tended to be higher in men than in women. We also found morphometric differences in the cerebellar tentorium among the CI groups. However, our results demonstrated that age was not effective on the cerebellar tentorium's morphometric organization. Cerebellar tentorium has a potential risk for injuries during posterior cranial fossa approaches. A number of studies aimed to evaluate patients' position during surgical interventions. However, the morphometric properties of cerebellar tentorium were not considered during the evaluation of patients' surgical position in previous studies. Though statistically significant, observed differences and correlations in tentorial morphometry were weak and likely of limited clinical utility. Findings contribute to anatomical reference data but may not be useful for inferring surgical guidance.