Dorsal extensions of the fastigium cerebelli: an anatomical study using magnetic resonance imaging
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Background and purpose
The fastigium cerebelli is an important topographical landmark for neurosurgeons and radiologists. However, few studies have characterized the morphology of the fastigium cerebelli. We aimed to investigate the fastigium cerebelli using postmortem specimens and magnetic resonance imaging (MRI) in vivo.
Materials and methods
Three cadaveric brains were midsagittally sectioned for observing the fastigium cerebelli. Additionally, 66 outpatients underwent MRI, including sagittal T1-weighted imaging, axial T2-weighted imaging, and coronal constructive interference in steady-state (CISS) sequence.
In the cadaveric specimens, the fastigium cerebelli was observed as a beak-like dorsal protrusion of the fourth ventricle. Its inner surface was observed as a small fovea. On serial CISS images, the fastigium cerebelli consistently possessed a pair of triangular-shaped, dorsal extensions lying parasagittally along the nodule. These extensions were classified as symmetrical, right-side dominant, or left-side dominant. The symmetrical type was the most predominant and comprised 60.6% of the extensions, while the right-side dominant and left-side dominant types comprised 13.6 and 25.8%, respectively. In 91% of the 66 patients, the number of slices covering the entirety of the dorsal extensions were the same on both sides. The fastigial angle (θ) formed by lines tangent to the superior and inferior medullary velums varied widely.
The fastigium cerebelli has a pair of dorsal extensions lying parasagittally along the nodule. Coronal CISS sequence is useful in delineating the fastigium cerebelli in vivo.
KeywordsFastigium cerebelli Dorsal extensions Morphological variations MRI
This study did not receive any grant funding.
ST and JCF-M developed the project of study. JCF-M performed cadaver dissection and collected anatomical data. HI and YY collected the imaging data. HO and HI analyzed the imaging data. ST wrote the manuscript.
Compliance with ethical standards
Conflict of interest
The authors have no conflicts of interest to declare regarding the materials or methods in this study or the findings specified in this paper.