The first vertebra is now called the atlas. The second vertebra, called the axis, is enlarged and the joint between the atlas and axis is specialized. The story of the evolution of the ...

The lateral C-spine as well as the open-mouth view are essential ... and overriding of the C1-C2 joint on one side (the so-called wink sign of atlantoaxial rotatory subluxation).

Normally, the shadows created by both sides of C2 superimpose, creating a distinct ring on the radiograph. Disruption of the ring suggests a fracture to the axis, particularly type III odontoid ...