Objective: To evaluate the anatomy and medical imaging characteristics in a study observing the atlanto-axial joint (AAJ) and related structures.
Methods: Eight cadaveric specimens of the AAJ segment were studied with both anatomical and imaging methods. The vertebral arteries of the AAJ segment (VA-A), the first and second cervical nerves (CN1, CN2) and synovial fold (SF) of the AAJ were observed and measured.
Result: After extending from the vertebral canal, the CN1 goes between the posterior arch of the atlas and VA-A, and the CN2 passes between the posterior arch of the atlas and axis, and is posterior to VAA. Among the eight cases, six were found in the SF in the central anterior AAJ and five in lateral. The vertebral arteries of the AAJ segment go along the AAJ with four curves, of which the second and fourth are away from the bone structure of the AAJ. The distance from CN1, CN2 to VA-A and that from the second, fourth curve of VA-A to AAJ is 0.0−2.2 mm, 0.0−3.6 mm and 0.0−4.8 mm, 2.0−7.9 mm respectively. There is no significant difference between the measurements made anatomically and those by the imaging method (p > 0.05).
Conclusion: The anatomical method has advantages in observing the CN and SF, while the imaging method shows clearly and directly the VA-A and AAJ. Both are mutually complementary with consistent measurements. The combined use of the two provides a new way to study the complicated anatomy in this region.