Cerebellar and Vermian Morphometry in Cadaveric Specimens: Reference Data for Posterior Fossa Approaches

INTRODUCTION: The cerebellum, with the vermis central to posture and gait, is critical for posterior fossa and fourth ventricular surgery, where millimetric accuracy ensures safety. However, reference morphometric data remain inconsistent, particularly for vermian depth and proportional indices. This study aimed to establish reproducible cadaveric reference values through volumetric, linear, and proportional analyses.
METHODS: Twenty-five formalin-fixed adult cerebellums were analyzed using volumetric displacement and standardized linear measurements. Proportional ratios were derived, and statistical comparisons were performed between hemispheres and across vermian levels.
RESULTS: The right hemisphere was larger than the left in both volume (69.04 ± 4.56 vs 67.12 ± 4.39 mL, p < 0.001) and width (49.00 ± 3.07 vs 47.08 ± 3.29 mm, p = 0.011), with asymmetry indices of 1.41% and 2.02%. Volume correlation was strong (r = 0.893, p < 0.001). Global shape ratios were stable, with height related to anteroposterior length (r = 0.456, p = 0.022). Vermian dimensions were consistent (length 25.14 ± 2.49 mm; uvular width 14.88 ± 2.09 mm) and showed no significant rostrocaudal depth variation. Regression revealed scaling, with vermis length predicted by anteroposterior length (β = 0.560, R² = 0.553, p < 0.001) and an inverse relation between anteroposterior length and uvular depth (β = –0.169, R² = 0.248, p = 0.011).
DISCUSSION AND CONCLUSION: These findings establish cadaveric reference values for the cerebellum and vermis, confirm mild right-sided asymmetry, and reveal stable proportions with coordinated scaling, including an inverse relationship between anteroposterior cerebellar elongation and uvular depth, thereby refining radiological interpretation and surgical planning.

Keywords: Cadaveric Study, Cerebellar Morphometry, Posterior Fossa Approaches, Reference Values, Vermian Anatomy, Volumetric Analysis