Ossification of the posterior atlantoaxial membrane and the transverse atlantal ligament.

Study Design: Case report.
Objective: To report a case of ossification of the posterior atlantoaxial membrane (PAAM) and ossification of the transverse ligament of the atlas (TAL).
Summary of Background Data: Ossification of the PAAM and TAL are both very rare clinical entities. This is the first case involving ossification of both the PAAM and TAL with the development of cervical myelopathy.
Methods: Patient's history, physical examination, radiographic evaluation, surgical treatment, and outcome are examined. Relevant literature is also reviewed.
Results: The patient's neurological symptoms significantly improved after posterior decompressive surgery.
Conclusion: Ossification of various parts of the spinal ligament have been reported previously. Among them, ossification of both the PAAM and TAL has never been reported previously and is thus extremely rare. Surgical intervention improved the neurological impairment.