Processes of vertebrae

A typical vertebra contains seven projections called the processes. They serve as the attachment sites for the back muscles and ligaments, levers for the actions of muscles and have facets for the articulation with adjacent vertebrae. 

The typical vertebrae have one unpaired and three paired processes:

The articular processes are located between the intersections of the pedicles and laminae. They form joints between adjacent vertebrae called the superior and inferior facet joints (zygapophyseal joints).