Atlas and axis joint: The joint between the atlas and axis bones. The atlas is the first cervical (neck) vertebra which is just under the head; it is named for Atlas, the Greek god who supported the world on his shoulders. The axis is the second cervical vertebra; it has what is called the odontoid process about which the atlas rotates.
The joint between the atlas and axis is a pivot type of joint. It allows the head turn from side to side. It is also called the atloaxoid joint.