A Cadaveric Study Of The Internal Occipital Crest And Vermian Fossa With Its Clinical Significance

ABSTRACT

Background: The anatomical variabilities of the internal occipital crest (IOC) and vermian fossa (VF) may influencethe related dural venous sinuses and further effect the flow of the cerebrospinal fluid. It is also associated withthe pathologies around the foramen magnum like Arnold Chiari malformation, certain cases of cerebellar corticaldysplasia.Aim: The present study was designed to explore and evaluate the morphological and morphometric details of theIOC and VF.Materials and Methods: The study was conducted on 40 adult cadavers (23 males & 17 females). The morphologyand morphometry of IOC and VF were studied. Based on the observations, the VF was classified into five typesType 1- classical (well defined fossa), Type II-short triangular, Type III- elongated triangular, Type IV-quadrangularand Type V-deviated.Results: The IOC was found to be variable both in terms of morphology and morphometry. The morphologicalobservations included varied shapes, i.e., sharp (65%), blunt (30 %) and ill-defined (5 %). The length of the IOCwas also variable with a mean length of 2.97 ± 0.16 cm. The mean width at upper, middle and lower levels were0.9 ± 0.10 cm, 0.75 ± 0.17 cm, 1.10 ± 0.12 cm respectively.The incidence of the VF was found to be about 80%. The VF was classified into types based on its varied shapeclassical (Type I ;56.25 %), short triangular (Type II ;21.87%), elongated triangular (Type III;12.5%) and quadrangular(Type 1V;6.25 %) respectively. In one specimen, the VF was deviated to the left side (type V ;3.12%). The mean lengthand width of the fossa were 1.67±0.34 cm and 1.80±0.34 cm respectively.Conclusion: The present study on the morphology and morphometry of the IOC and the VF may serve as databaseand further help clinicians to improve the diagnosis and therapeutic performances in the posterior cranialfossa.