The joint between the atlas and axis is:

First cervical vertebra is known as Atlas. Second cervical vertebra is known as Axis. Special joint between Atlas, Axis and Occipital bone: Atlanto-Occipital joint: It is a synovial joint - ellipsoid type. Allows flexion and extension of head on neck (as like nodding up and down). Atlanto-Axial joint: It is a pivot type of joint. Allows rotatory movement of head on neck (as like saying 'NO' - right and left rotation). The dens of axis forms a pivot, around which the atlas rotates, permitting rotatory motion of  neck possible.