The zygapophysial joint, also known as the facet joint, is a synovial joint located between the vertebrae in the spine. Synonyms for this joint include apophyseal joint, posterior zygapophyseal joint, z-joint, and facet articulation. These joints function to allow for movement and stability in the spine, while also providing protection for the spinal cord. Additionally, these joints can become painful or dysfunctional due to injury or degeneration, leading to conditions such as facet syndrome or spinal arthritis. Understanding the various synonyms for this joint can aid in the diagnosis and treatment of spinal issues.