Yes ! I have all the symptoms of Arnold Chiari, but no classic tonsillar herniation. Now I understand that some doctors are recognizing "Chiari O Malformation. " - at the Univ. of Alabama - Dr. Grubb for one. Now I just got a diagnosis of spina bifida occulta and tethered spinal cord. I believe there is a connection between these and the ACM. I have read that all children born with spina bifida ( which is the severe form of spina bifida occulta) also have ACM. There is new research in "Spine" - January - out of Japan - that connects ACM/tonsillar ectopia to 'idiopathic scoliosis." The tethered cord literature says that scoliosis is caused by a tethered cord which prevents the spinal cord from ascending the spinal canal during adolescent growth. The body compensates by twisting the bony part of the spine. My spina bifida occulta was missed on 2 MRIs and a CAT scan, caught on some chiropractic x-rays and now confirmed by M.D.s The tethering is being missed by radiologists. I am tethered at S-3. Try to consult an expert neurosurgeon in spina bifida, since tethered cord is common with the regular SB. Good luck.