RESUMEN
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 types:Type 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 shape:classical (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.
RESUMEN
Aim: The internal occipital crest (IOC) occasionally diverges at the lower end around the foramen magnum, giving rise to roughly triangular shaped vermian fossa. Variations occur in the vermian fossa in the form of shape and size. There is paucity of such study in the available literature, hence the present study was undertaken to evaluate the incidence, morphology and morphometry of the VF in the adult population of Western Uttar Pradesh. Material and method: Adult human 30 cranial bases (vault removed) and 25 occipital bones of both the sexes, which were obtained from the osteology section of department of anatomy in LLRM Medical College, Meerut (UP), formed the basis for this study. The fossa were macroscopically examined and classified into Type1 (triangular shape), Type 2 (quadrangular shape), and Type 3or atypical type (fossa shape was other than the above said). Result: Out of the 55 specimens the VF was observed in 40(72.7%) specimens, and was found absent in the remaining 15(27.2%) specimens. The VF was triangular shaped in 29(72.5%) specimens and quadrangular in 4(10.0%) specimens. In 7(17.5%) specimens it was having unusual morphology and considered as atypical. Among the atypical types, two specimens were having deep fossa, one was having partitioned VF, and four of them had widened VF. The average length and width of the fossa were 14.2 mm and 12.1 mm respectively. Conclusion: The incidence is higher in our study as compared to the previous studies and it might be because of racial variations. Accurate knowledge of the variability of the human morphology and morphometry improves the diagnosis and therapeutic performance and also helpful in the study of the diseases that cause alterations of size and morphology of inferior vermis of cerebellum and clinician who operates intracranially or interprets radiological imaging. Hence this study is enlightening for the neuroanatomists and morphologists.