title: Uncovertebral joint injury in cervical facet dislocation: the headphones sign.
abstract: The purpose of our study is to demonstrate the uncovertebral mal-alignment as a reliable indirect sign of cervical facet joint dislocation. We examined the uncovertebral axial plane alignment of 12 patients with unilateral and bilateral cervical facet joint dislocation (UCFJD and BCFJD, respectively), comparing its frequency to the reverse hamburger bun sign on CT and MR axial images. Of the seven cases with BCFJD, five clearly demonstrated the diagnostic reverse facet joint hamburger bun sign on CT and MR images, but in two cases this sign was not detectable. In the five cases with UCFJD, four demonstrated the reverse hamburger bun sign on both CT and MRI. In one case the reverse hamburger bun sign was not seen adequately with either image modality, but the facet dislocation was identified on sagittal imaging. The uncovertebral mal-alignment was detected in all 12 cases. Normally, the two components of the uncovertebral joint enjoy a concentric relationship that in the axial plane is reminiscent of the relationship of headphones with the wearer's head. We name this appearance the 'headphones' sign. Radiologists should be aware of the headphones sign as a reliable indicator of facet joint dislocation on axial imaging used in the assessment of cervical spine injuries.
authors.affiliation: Department of Radiology, Robert Jones and Agnes Hunt Orthopaedic and District Hospital, SY10 7AG, Oswestry, England, UK.
authors.forename: Francesco
authors.initials: F
authors.lastname: Palmieri
authors.forename: Victor N
authors.initials: VN
authors.lastname: Cassar-Pullicino
authors.forename: Claudia
authors.initials: C
authors.lastname: Dell'Atti
authors.forename: Radhesh K
authors.initials: RK
authors.lastname: Lalam
authors.forename: Bernhard J
authors.initials: BJ
authors.lastname: Tins
authors.forename: Prudencia N M
authors.initials: PN
authors.lastname: Tyrrell
authors.forename: Iain W
authors.initials: IW
authors.lastname: McCall
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000293:injuries*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D004204:Joint Dislocations / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D021801:Zygapophyseal Joint / Q000293:injuries*