28-year-old female with headaches for the past three weeks, worse in the morning. There is no evidence of intracranial hemorrhage, mass, or acute infarct. The brain parenchyma and pituitary gland appear unremarkable. There is approximately 3-4 mm inferior protrusion of the cerebellar tonsils through the foramen magnum. There is apparent mild crowding of the foramen magnum and a mildly pointed morphology of the inferior aspect of the cerebellar tonsils bilaterally. There is no abnormal intracranial enhancement. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The major cerebral flow voids are intact. The orbits, skull, paranasal sinuses, and scalp soft tissues are grossly unremarkable.
1. No evidence of acute intracranial hemorrhage, mass, or acute infarct.2. Bilateral cerebellar tonsillar ectopia. The relevance of this finding is uncertain so correlation with symptoms is suggested.