 |  |  |
| T1 sagittal pre gad | T2 sagittal | T2 axial |
Diagnosis: Chiari I malformation with a small syrinx.
Chiari I malformation is characterized by peg-like cerebellar tonsils which are herniated a variable amount through the foramen magnum. The tonsils may be normally displaced 6 mm below the foramen magnum before the age of 10. From 10 - 30 years of age, 5 mm is normal while from 30 - 70, 4 mm is acceptable. Patients often present with vague neurologic complaints which may mimic multiple sclerosis. Associated abnormalities include a syrinx which is present in 1/3 of patients and hydrocephalus in 1/4. Abnormalities of the skull base and upper cervical spine may be present in 1/4 including basilar invagination most commonly, Klippel-Feil anomaly and incomplete ossification of C1. Related Cases
