A unique bilateral variation of lateral atlantoaxial joint meniscoid morphology: case report

Advances in understanding of the anatomy of lateral atlantoaxial joint meniscoids have lead to theories regarding the clinical significance of these structures in head and neck pain. However, there is a paucity of evidence pertaining to anatomical variations of lateral atlantoaxial joint meniscoids in cadaveric research or in vivo. We present the case of a 57-year-old female with a variation in the morphology of the lateral atlantoaxial joint meniscoids. The subject was a symptom-free volunteer in an anatomical study employing magnetic resonance imaging. On review of her scans, the dorsal meniscoid of both left and right lateral atlantoaxial joints extended across the entirety of the articular cavities, with no visible ventral meniscoid. This variation has not previously been reported, and may have clinical implications in the context of cervical spine trauma. With increasing evidence regarding the pathoanatomical potential of lateral atlantoaxial joint meniscoids, appreciation of anatomical variation in a symptom-free population may have future clinical utility. Keywords: anatomy; atlantoaxial joint; cervical spine; meniscoid; synovial folds