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A case of fourth atlanto-axial facet joint: anatomical description
Xing-Wen Wang1,2, Feng-Zeng Jian1, Feng Ling3
1Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, 45 Changchun St, Beijing, 100053, People's Republic of China.
Purpose:
To report a rare fourth atlanto-axial joint.
Methods:
A cadaveric specimen of a young male adult from occiput to C4 was dissected for anatomical study of craniocervical region. A true fourth atlanto-axial joint was confirmed. Its morphological characteristics were described.
Results:
The fourth atlantoaxial joint is rarely seen. The possible embryogenesis is discussed. This case raises an anatomical possibility of a new variant in this region.
Conclusions:
A unique case with an anatomically proven fourth atlantoaxial joint is reported. This anomaly can lead to misdiagnosis. CT scan coupled with MRI can facilitate accurate diagnosis.
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