TY - JOUR T1 - Vacuum phenomenon as a sign of an ununited, unstable dens fracture. JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1144 LP - 1145 VL - 8 IS - 6 AU - A L Williams AU - G F Carrera AU - J P Grogan AU - D P Ullrich Y1 - 1987/11/01 UR - http://www.ajnr.org/content/8/6/1144.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -