Lhermitte's Sign, sometimes calle the Barber Chair phenomenon, is an electrical sensation that runs down the back and into the limbs, and is produced by bending the neck forward. The sign suggests a lesion of the dorsal columns of the cervical cord or of the caudal medulla. Although often considered a classic finding in multiple sclerosis, it can be caused by a number of conditions, including Behçet's disease, trauma, radiation myelopathy,vitamin B12 deficiency (subacute combined degeneration), and compression of the spinal cord in the neck from any cause such as cervical spondylosis, disc herniation, tumor, and Arnold-Chiari malformation.