RT Journal Article SR Electronic T1 Protrusion of the posterior longitudinal ligament simulating herniated lumbar intervertebral disc. JF Journal of Neurology, Neurosurgery & Psychiatry JO J Neurol Neurosurg Psychiatry FD BMJ Publishing Group Ltd SP 61 OP 66 DO 10.1136/jnnp.31.1.61 VO 31 IS 1 A1 R A Beatty A1 O Sugar A1 T A Fox YR 1968 UL http://jnnp.bmj.com/content/31/1/61.abstract AB