Final answer:
The atlantoaxial joint is an example of a pivot joint that allows the head to rotate on top of the axis.
Step-by-step explanation:
The atlantoaxial joint, between the atlas and axis, is an example of a pivot joint. This joint allows the atlas to rotate on top of the axis, allowing the head to move toward the right or left, like when shaking your head "no". The joint consists of the dens portion of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), with the dens held in place by a ligament.