title: Christmas tree sign.
authors.affiliation: Department of Neurosciences, Charing Cross Hospital, London, England.
authors.forename: K
authors.initials: K
authors.lastname: Ashkan
authors.forename: A T
authors.initials: AT
authors.lastname: Casey
mesh_terms: D001416:Back Pain / Q000150:complications / Q000209:etiology; D002420:Cauda Equina / Q000473:pathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D017253:Neurofibromatoses / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D012585:Sciatica / Q000150:complications