The zygosphene-zygantrum articulation is an accessory joint between vertebrae found in several lepidosauromorph reptiles.
[2] This joint is found in snakes, lacertids, teiids, Gymnophthalmids as well as in some iguanids and cordylids.
[3] It is also found in several fossil groups such as plesiosaurians, nothosaurians and pachypleurosaurians.
[4] It is absent in today's Monitor lizard (Varanus), but occurs in fossil Varanids.
While it permits horizontal and vertical movements of the vertebral column, it prevents rotations of the single vertebrae against each other.