VARIATION OF THE FORM OF THE FORAMEN OCCIPITALE MAGNUM
Nowadays, in the diagnosis of the extensive endocranial processes, major significance is attributed to the secondary changes in the skull that appear also in the X-Rays. Despite some successes in the development of the X-ray anatomy of the skull and in the study of secondary changes, there are major difficulties in reading the X-rays. This is explained by the fact that the variability in the construction of the various parts of the skull is more frequent, especially at its base and in the area of the great occipital opening.
In the literature it can hardly be found how the variations in the shape of the great occipital opening are described and peculiarities in the construction of its rear end. In healthy persons, the semi-axial X-rays of the great occipital opening have an oval shape, a clear and smooth back end, surrounded by a solid bone cylinder that passes toward the middle in the vertically set ridge of the occipital bone.
When tumors in the posterior cranial fossa are described, many authors note changes in the great occipital opening in the form of osteoporosis, atrophy, and slinging the skull at the posterior end of the opening, with local cleavers and leveling of the corresponding part of the occipital bone, known as the Bapcin symptom.
The anatomical variation of the form of the foramen occipital magnum was axsamined on 80 calvarials. With detail analysis we identified three normal variations of the form of the foramen occipital magnum : the oval (48 cases), the round (21 cases) and the anomalous form (11 cases). Also the dorsal end and osseous configuration of the occipital bone was examined.
The importance of this study is it’s prognostic and diagnostic application in the clinical and roentgengratic research.
Greatest difficulties arise in the malignant brainstem process, especially when the invasive process goes to the middle of the back of the great occipital opening.
Knowledge of foramen occipital magnum variations is important for surgeons in pereforming many procedures and it may help to avoid clinical coplications, especially, during radiological examination.
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