one of the small flat projections on the surfaces of the arches of the vertebrae on either side, at the point where the pedicles and laminae join, forming the zygapophysial joint surfaces; superior articular process, diapophysis; one of the anticular processes on the superior surface of the vertebral arch; inferior articular process, one of the articular processes on the inferior surface of the vertebral arch. Syn: processus articularis [NA], zygapophysis [NA].