 Images are slightly limited by patient motion. There is again abnormal caudal extension of the cerebellar tonsils below the level of foramen magnum, extending 11 mm. Overall, the cerebral tonsils remain rounded in configuration without significant pointing. There is moderate associated crowding at this level. Biphasic CSF flow is again diminished dorsally at the level of the foramen magnum.The cervical spine is in normal alignment, with straightening of the normal cervical lordosis. There is minimal disc narrowing at C4-C5 and C5-C6. The vertebral body and disk heights are otherwise well-maintained. No worrisome focal marrow signal abnormality is appreciated. The spinal cord is of normal caliber and signal.There is no significant disk bulge, herniation, spinal canal or foraminal stenosis within the cervical spine. There is trace fluid within mastoid air cells bilaterally.
Abnormal caudal extension of the cerebellar tonsils 11 mm below the level of the foramen magnum, although they remain rounded in morphology, with moderate crowding of structures. Diminished CSF flow dorsally at this level. Please correlate clinically for possible Chiari I malformation.