Zygapophysial joint

The facet joints ( articulationes processuum articularium or articulationes zygapophysiales ) are used in addition to the intervertebral disc and the spine bands of the articulated connection of adjacent vertebrae. The articular surfaces of the joints are paired on the two lower ( rear in animals ) and the two upper ( front ) articular processes ( processus articulares ) of successive vertebrae. There are so-called " flat joints " or " facet joints " in which the movement is parallel to the joint surfaces, and which are therefore also referred to as " sliding joints ". The facet joints is determined primarily by the direction of movement, while the intervertebral discs and spinal ligaments above all limit the range of motion.

A wear-related ossification of the facet joints is called spondylarthritis.