Chiari I malformation with syrinx

This is a sagittal T2-weighted MR image of the cervical spine and shows abnormal position of the cerebellar tonsils (yellow arrow) below the foramen magnum (dashed line), indicating a Chiari I malformation. In this case, the malformation is associated with a huge syrinx (red arrows) that extends throughout the spinal cord. In some cases of Chiari I malformation, the patient will be asymptomatic however many cases are associated with a syrinx and/or hydrocephalus and may therefore present with symptoms such as upper or lower limb weakness or headaches.