<s>[INST] Ive been experinencing a lot of neck pain an shoulder pain along with headaches dizziness numbness an nausea. I had a MRI of my neck an my results said I have low lying cerebellar tonsills. The doc didnt know much about this other than I needed to have a MRI done on my brain Im wondering what my next step should be? [/INST] Hi, Thanks for writing in. The cerebellar tonsils are the most inferior portion of the cerebellum, a part of the hind brain which is important for motor coordination. Normally, these tonsils are wholly inside the skull. In the case of Arnold-Chiari, the tonsils are low-lying, below their normal level. It can cause severe headaches. You should discuss with your neurosurgeon and see if you really need a surgical decompression or methods to regularize CSF flow from ventricles through the cervical cord. </s>